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Particle matter (PM) is a complex mixture of particles suspended in the air, mainly caused by fuel combustion from vehicles and industry, and has been related to pulmonary and cardiovascular diseases. The Metropolitan Area of Aburrá Valley in Colombia is the second most populous urban agglomeration in the country and the third densest in the world, composed of ten municipalities. Examining the physicochemical properties of PM is crucial in comprehending its composition and its effects on human health, as it varies based on the socioeconomic dynamics specific to each city. This study characterized the PM collected from the north, south, and central zones to evaluate its chemical composition and morphology. Different elements such as silicon, carbon, aluminum, potassium, calcium, sodium, iron, magnesium, and copper and the presence of unburned fuel, motor oil, and silicon fibers were identified. In vitro and in silico studies were conducted to evaluate the toxicity of the PM, and it was found that the PM collected from the central zone had the greatest impact on cell viability and caused DNA damage. The in silico study demonstrated that PM has concentration-dependent proarrhythmic effects, reflected in an action potential duration shortening and an increased number of reentries, which may contribute to the development of cardiac arrhythmias. Overall, the results suggest that the size and chemical composition of ambient PM can induce toxicity and play an important role in the generation of arrhythmias, This work was supported by the Ministerio de Ciencia Tecnología e Innovación (MINCIENCIAS) from Colombia, through grant No. 120677757994 and by the Dirección General de Política Científica de la Generalitat Valenciana PROMETEO/2020/043. The work of Palacio was supported by the “Programa de excelencia doctoral del Bicentenario 2019” of MINCIENCIAS. The work of Durango-Giraldo and Zapata-Hernandez was supported by the “Convocatoria para el fortalecimiento de proyectos en ejecución de CTeI en ciencias de la salud con talento joven e impacto regional” of MINCIENCIAS, Postprint (published version)

Increasing evidence suggests that natural killer (NK) cells are composed of distinct functional subsets. This multifunctional role has made them an attractive choice for anticancer immunotherapy. A functional NK cell repertoire is generated through cellular education, resulting in a heterogeneous NK cell population with distinct capabilities responding to different stimuli. The application of a high-throughput droplet-based microfluidic platform allows monitoring of NK cell-target cell interactions at the single-cell level and in real-time. A variable response of single NK cells toward different target cells is observed, and a distinct population of NK cells (serial killers) capable of inducing multiple target lysis is identified. By assessing the cytotoxic dynamics, it is shown that single umbilical cord blood-derived CD34+ hematopoietic progenitor (HPC)-NK cells display superior antitumor cytotoxicity. With an integrated analysis of cytotoxicity and cytokine secretion, it is shown that target cell interactions augment cytotoxic as well as secretory behavior of NK cells. By providing an integrated assessment of NK cell functions by microfluidics, this study paves the way to further functionally characterize NK cells ultimately aimed to improve cancer immunotherapy.

BACKGROUND: Immune-related adverse events due to immune checkpoint inhibitors (ICIs) are not always effectively treated using glucocorticoids and it may negatively affect the antitumor efficacy of ICIs. Interventional studies of alternatives to glucocorticoids are lacking. We examined whether interleukin-6 blockade by tocilizumab reduced ICI-induced colitis and arthritis. PATIENTS AND METHODS: Patients with solid cancer experiencing Common Terminology Criteria for Adverse Events (CTCAE v5.0) grade >1 ICI-induced colitis/diarrhea (n=9), arthritis (n=9), or both (n=2) were recruited and treated with tocilizumab (8 mg/kg) every 4 weeks until worsening or unacceptable toxicity. Patients were not allowed to receive systemic glucocorticoids and other immunosuppressive drugs within the 14-day screening period. The primary endpoint was clinical improvement of colitis and arthritis, defined as ≥1 grade CTCAE reduction within 8 weeks. Secondary endpoints were improvements and glucocorticoid-free remission at week 24; safety; radiologic, endoscopic, and histological changes; and changes in plasma concentrations of C reactive protein, cytokines (IL-6, IL-8, and IL-17), and YKL-40. RESULTS: Nineteen patients were available for efficacy analysis; one patient was excluded due to pancreatic insufficiency-induced diarrhea. Patients received treatment with pembrolizumab (n=10) or nivolumab (n=4) as monotherapy or ipilimumab and nivolumab (n=5) combined. Seven patients had been initially treated with glucocorticoids, and two of them also received infliximab. Ten patients continued ICI therapy during tocilizumab treatment. The primary endpoint was achieved in 15 of 19 (79%) patients. Additional one patient had ≥1 grade reduction at week 10, and another patient had stabilized symptoms. At week 24, ongoing improvement without glucocorticoids (n=12), including complete remission (n=10), was noted. Five patients had grades 3-4 treatment-related adverse events, which were manageable a

The chimeric antigen receptor (CAR) is an artificial molecule engineered to induce cytolytic T cell reactions in tumors. Generally, this molecule combines an extracellular single-chain variable fragment (scFv) able to recognize tumor-associated epitopes together with the intracellular signaling domains that are required for T cell activation. When expressed by T cells, the CAR enables the recognition and subsequent destruction of cancer cells expressing the complementary antigen on their surface. Although the clinical application for CAR T cells is currently limited to some hematological malignancies, researchers are trying to develop CAR T cell-based therapies for the treatment of solid tumors. However, while in the case of CD19, or other targets restricted to the hematopoietic compartment, the toxicity is limited and manageable, the scarcity of specific antigens expressed by solid tumors and not by healthy cells from vital organs makes the clinical development of CAR T cells in this context particularly challenging. Here we summarize relevant research and clinical trials conducted to redirect CAR T cells to surface antigens in solid tumors and cancer stem cells with a focus on colorectal cancer and glioblastoma. Finally, we will discuss current knowledge of altered glycosylation of CSCs and cancer cells and how these novel epitopes may help to target CAR T cell-based immunotherapy in the future.

Heparin-binding hemagglutinin (HBHA), a surface protein of Mycobacterium tuberculosis, is an attractive vaccine candidate and marker of protective immunity against tuberculosis, although the mechanisms underlying this protective immunity are not fully understood. Comparisons of the immune responses of latently M. tuberculosis-infected (LTBI) subjects to those of patients with active tuberculosis (aTB) may help to identify surrogate markers of protection, as LTBI subjects are most often lifelong protected against the disease. HBHA was shown to induce strong Th1 responses and cytotoxic CD8+ responses in LTBI subjects, but additional mechanisms of control of M. tuberculosis infection remain to be identified. In this study, using HBHA-induced blast formation as a readout of specific T lymphocyte activation, we report the presence in M. tuberculosis-infected subjects of HBHA-induced CD4+ T cell blasts that degranulate, as measured by surface capture of CD107a. This suggests the induction by HBHA of a CD4+ T cell subset with cytolytic function, and as nearly half of these cells also contained IFN-γ, they had both Th1 and cytotoxic characteristics. We further identified a CD4+ T lymphocyte subset producing IFN-γ together with a combination of mediators of cytotoxicity, i.e. perforin, granzymes, and granulysin, and we called them polycytotoxic CD4+ T lymphocytes. Interestingly, whereas purified protein derivative induced such cells in both LTBI subjects and patients with aTB, HBHA-specific polycytotoxic CD4+ T lymphocytes were detected in LTBI subjects and not in patients with pulmonary aTB. To our knowledge, we thus identified a new HBHA-induced CD4+ T cell subset that may contribute to the control of M. tuberculosis infection., info:eu-repo/semantics/published

One major hurdle to the success of adoptive T-cell therapy is the identification of antigens that permit effective targeting of tumors in the absence of toxicities to essential organs. Previous work has demonstrated that T cells engineered to express chimeric antigen receptors (CAR-T cells) targeting the murine homolog of the colorectal cancer antigen GUCY2C treat established colorectal cancer metastases, without toxicity to the normal GUCY2C-expressing intestinal epithelium, reflecting structural compartmentalization of endogenous GUCY2C to apical membranes comprising the intestinal lumen. Here, we examined the utility of a human-specific, GUCY2C-directed single-chain variable fragment as the basis for a CAR construct targeting human GUCY2C-expressing metastases. Human GUCY2C-targeted murine CAR-T cells promoted antigen-dependent T-cell activation quantified by activation marker upregulation, cytokine production, and killing of GUCY2C-expressing, but not GUCY2C-deficient, cancer cells in vitro. GUCY2C CAR-T cells provided long-term protection against lung metastases of murine colorectal cancer cells engineered to express human GUCY2C in a syngeneic mouse model. GUCY2C murine CAR-T cells recognized and killed human colorectal cancer cells endogenously expressing GUCY2C, providing durable survival in a human xenograft model in immunodeficient mice. Thus, we have identified a human GUCY2C-specific CAR-T cell therapy approach that may be developed for the treatment of GUCY2C-expressing metastatic colorectal cancer.

Osteoclasts reside on bone and are the main bone resorbing cells playing an important role in bone homeostasis, while natural killer (NK) cells are bone-marrow-derived cells known to play a crucial role in immune defence against viral infections. Although mature NK cells traffic through bone marrow as well as to inflammatory sites associated with enhanced bone erosion, including the joints of patients with rheumatoid arthritis, little is known about the impact NK cells may have on mature osteoclasts and bone erosion. We studied the interaction between human NK cells and autologous monocyte-derived osteoclasts from healthy donors in vitro. We show that osteoclasts express numerous ligands for receptors present on activated NK cells. Co-culture experiments revealed that interleukin-15-activated, but not resting, NK cells trigger osteoclast apoptosis in a dose-dependent manner, resulting in drastically decreased bone erosion. Suppression of bone erosion requires contact between NK cells and osteoclasts, but soluble factors also play a minor role. Antibodies masking leucocyte function-associated antigen-1, DNAX accessory molecule-1 or tumour necrosis factor-related apoptosis-inducing ligand enhance osteoclast survival when co-cultured with activated NK cells and restore the capacity of osteoclasts to erode bone. These results suggest that interleukin-15-activated NK cells may directly affect bone erosion under physiological and pathological conditions.

BACKGROUND: IL-17, a Th17 cell-derived proinflammatory molecule, has been found to play an important role in the pathogenesis of autoimmune diseases, including multiple sclerosis (MS) and its animal model, experimental autoimmune encephalomyelitis (EAE). While IL-17 receptor (IL-17R) is expressed in many immune-related cells, microglia, and astrocytes, it is not known whether IL-17 exerts a direct effect on neural stem cells (NSCs) and oligodendrocytes, thus inducing inflammatory demyelination in the central nervous system. METHODS: We first detected IL-17 receptor expression in NSCs with immunostaining and real time PCR. We then cultured NSCs with IL-17 and determined NSC proliferation by neurosphere formation capability and cell number count, differentiation by immunostaining neural specific markers, and apoptosis of NSCs by flow cytometry. RESULTS: NSCs constitutively express IL-17R, and when the IL-17R signal pathway was activated by adding IL-17 to NSC culture medium, the number of NSCs was significantly reduced and their ability to form neurospheres was greatly diminished. IL-17 inhibited NSC proliferation, but did not induce cytotoxicity or apoptosis. IL-17 hampered the differentiation of NSCs into astrocytes and oligodendrocyte precursor cells (OPCs). The effects of IL-17 on NSCs can be partially blocked by p38 MAPK inhibitor. CONCLUSIONS: IL-17 blocks proliferation of NSCs, resulting in significantly reduced numbers of astrocytes and OPCs. Thus, in addition to its proinflammatory role in the immune system, IL-17 may also play a direct role in blocking remyelination and neural repair in the CNS.

Recently it has become clear that interferon (IFN)-α, a type I interferon produced rapidly in response to infection, not only plays a key role in innate immunity, but also promotes adaptive immune responses by influencing the production or function of other cytokines. During infections IFN-α fosters the production of IL-15, which plays a pivotal role in the development, survival and function of NK cells and recruitment and activation of T cells. Since these two cytokines exert overlapping functions during infections, this investigation was undertaken to study the priming effect of IFN-α on the effect of IL-15 on human T and NK cells. We show that IFN-α induces an increased expression of IL-15Rα in human activated peripheral T cells, and in CD8(+) and CD4(+) T-cell lines. Functionally, the IFN-α-enhanced IL-15Rα expression resulted in an enhanced IL-15-mediated phosphorylation of STAT5 and STAT3 followed by a further increase in IL-15Rα expression. Moreover, IFN-α significantly increased the IL-15-induced cytotoxic activity of freshly isolated T and NK cells. Taken together, our data show that IFN-α boosts signaling and functional effects of IL-15, at least in part by fostering the increased IL-15R expression, thus add new facet to the emerging role of IFN-α as an important primer of adaptive immune responses.

IL-10-producing CD4 + type 1 regulatory T (Tr1) cells, defined based on their ability to produce high levels of IL-10 in the absence of IL-4, are major players in the induction and maintenance of peripheral tolerance. Tr1 cells inhibit T-cell responses mainly via cytokine-dependent mechanisms. The cellular and molecular mechanisms underlying the suppression of APC by Tr1 cells are still not completely elucidated. Here, we defined that Tr1 cells specifically lyse myeloid APC through a granzyme B (GZB)- and perforin (PRF)-dependent mechanism that requires HLA class I recognition, CD54/lymphocyte function-associated antigen (LFA)-1 adhesion, and activation via killer cell Ig-like receptors (KIRs) and CD2. Notably, interaction between CD226 on Tr1 cells and their ligands on myeloid cells, leading to Tr1-cell activation, is necessary for defining Tr1-cell target specificity. We also showed that high frequency of GZB-expressing CD4 + T cells is detected in tolerant patients and correlates with elevated occurrence of IL-10-producing CD4 + T cells. In conclusion, the modulatory activities of Tr1 cells are not only due to suppressive cytokines but also to specific cell-to-cell interactions that lead to selective killing of myeloid cells and possibly bystander suppression. © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim

Rhaphidophora korthalsii (Araceae) is a root-climber plant which has been previously identified as splenocyte immunostimulator. The purpose of this study was to examine the in vitro and in vivo immunomodulatory effect of R. korthalsii methanol extract on immune cell proliferation, cytokine expression and cytotoxicity. More specifically, immunomodulatory effects of R. korthalsii methanol extract on the stimulation of NK cells activity and cytotoxicity against HepG2 monolayer and spheroid culture were determined. Immune cells [peripheral blood mononuclear cells (PBMC) and mice splenocytes] treated with this extract resulted in stimulation of cell proliferation, cytokine expression and cytotoxicity in dose and time dependent manner. For the in vivo immunostimulatory effect study, unlike rIL-2 which degraded rapidly, the stimulatory effect from the extract managed to last until day 15. In order to understand the activation of NK cells by R. korthalsii methanol extract, NK cells were treated directly or indirectly. Both direct and indirect stimulated NK cells showed high-level expression of cell surface FasL, NKG2D, 16B4 and extra-cellular IFN-γ and TNF-α. These activations contributed to the killing of NK cells against HepG2 monolayer cells through Granzyme B mitochondria caspases dependent secretory apoptosis pathway where DNA fragmentation, phosphatidylserine (PS) externalisation, caspase 3, caspase 8, caspase 9 up-regulation and XIAP, Bid downregulation were observed. Apart from that, extract stimulated NK cells which caused cell death on the HepG2 spheroid and inhibited the HepG2 cell invasion, suggesting that R. korthalsii methanol extract was a potential agent to inhibit liver tumour metastasis. Our findings indicated a potential IL-2 free immunotherapy through direct and indirect R. korthalsii activation on NK cells which can further induce apoptosis on the HepG2 monolayer and spheroid culture.

Rhaphidophora korthalsii (Araceae) is a root-climber plant which has been previously identified as splenocyte immunostimulator. The purpose of this study was to examine the in vitro and in vivo immunomodulatory effect of R. korthalsii methanol extract on immune cell proliferation, cytokine expression and cytotoxicity. More specifically, immunomodulatory effects of R. korthalsii methanol extract on the stimulation of NK cells activity and cytotoxicity against HepG2 monolayer and spheroid culture were determined. Immune cells [peripheral blood mononuclear cells (PBMC) and mice splenocytes] treated with this extract resulted in stimulation of cell proliferation, cytokine expression and cytotoxicity in dose and time dependent manner. For the in vivo immunostimulatory effect study, unlike rIL-2 which degraded rapidly, the stimulatory effect from the extract managed to last until day 15. In order to understand the activation of NK cells by R. korthalsii methanol extract, NK cells were treated directly or indirectly. Both direct and indirect stimulated NK cells showed high-level expression of cell surface FasL, NKG2D, 16B4 and extra-cellular IFN-γ and TNF-α. These activations contributed to the killing of NK cells against HepG2 monolayer cells through Granzyme B mitochondria caspases dependent secretory apoptosis pathway where DNA fragmentation, phosphatidylserine (PS) externalisation, caspase 3, caspase 8, caspase 9 up-regulation and XIAP, Bid downregulation were observed. Apart from that, extract stimulated NK cells which caused cell death on the HepG2 spheroid and inhibited the HepG2 cell invasion, suggesting that R. korthalsii methanol extract was a potential agent to inhibit liver tumour metastasis. Our findings indicated a potential IL-2 free immunotherapy through direct and indirect R. korthalsii activation on NK cells which can further induce apoptosis on the HepG2 monolayer and spheroid culture.

The association between HLA-B 2705 and the immune control of human immunodeficiency virus type 1 (HIV-1) has previously been linked to the targeting of the HLA-B 2705-restricted Gag epitope KRWIILGLNK (KK10) by CD8(+) T cells. In order to better define the mechanisms of the HLA-B 2705 immune control of HIV, we first characterized the CD8(+) T-cell responses of nine highly active antiretroviral therapy (HAART)-naïve B 2705-positive subjects. Unexpectedly, we observed a strong response to an HLA-B 2705-restricted Pol epitope, KRKGGIGGY (KY9), in 8/9 subjects. The magnitude of the KY9 response was only marginally lower than that of the KK10-specific response (median, 695 versus 867 spot-forming cells [SFC]/million peripheral blood mononuclear cells [PBMCs]; not significant [NS]), and viral escape mutants were observed in both KY9 and KK10, resulting from selection pressure driven by the respective CD8(+) T-cell response. By comparing inhibitions of viral replication by CD8(+) T cells specific for the Gag KK10, Pol KY9, and Vpr VL9 HLA-B 2705-restricted epitopes, we observed a consistent hierarchy of antiviral efficacy (Gag KK10 > Pol KY9 > Vpr VL9). This hierarchy was associated with early recognition of HIV-1-infected cells, within 6 h of infection, by KK10- and KY9-specific CD8(+) T cells but not until 18 h postinfection by VL9-specific CD8(+) T cells. There was no association between antiviral efficacy and proliferative capacity, cytotoxicity, polyfunctionality, or T-cell receptor (TCR) avidity. These data are consistent with previous studies indicating an important role for the B 2705-Gag KK10 response in the control of HIV but also suggest a previously unrecognized role played by the subdominant Pol-specific KY9 response in HLA-B 2705-mediated control of HIV and that the recognition of HIV-infected cells by CD8(+) T cells early in the viral life cycle may be important for viral containment in HIV-infected individuals.

The association between HLA-B 2705 and the immune control of human immunodeficiency virus type 1 (HIV-1) has previously been linked to the targeting of the HLA-B 2705-restricted Gag epitope KRWIILGLNK (KK10) by CD8(+) T cells. In order to better define the mechanisms of the HLA-B 2705 immune control of HIV, we first characterized the CD8(+) T-cell responses of nine highly active antiretroviral therapy (HAART)-naïve B 2705-positive subjects. Unexpectedly, we observed a strong response to an HLA-B 2705-restricted Pol epitope, KRKGGIGGY (KY9), in 8/9 subjects. The magnitude of the KY9 response was only marginally lower than that of the KK10-specific response (median, 695 versus 867 spot-forming cells [SFC]/million peripheral blood mononuclear cells [PBMCs]; not significant [NS]), and viral escape mutants were observed in both KY9 and KK10, resulting from selection pressure driven by the respective CD8(+) T-cell response. By comparing inhibitions of viral replication by CD8(+) T cells specific for the Gag KK10, Pol KY9, and Vpr VL9 HLA-B 2705-restricted epitopes, we observed a consistent hierarchy of antiviral efficacy (Gag KK10 > Pol KY9 > Vpr VL9). This hierarchy was associated with early recognition of HIV-1-infected cells, within 6 h of infection, by KK10- and KY9-specific CD8(+) T cells but not until 18 h postinfection by VL9-specific CD8(+) T cells. There was no association between antiviral efficacy and proliferative capacity, cytotoxicity, polyfunctionality, or T-cell receptor (TCR) avidity. These data are consistent with previous studies indicating an important role for the B 2705-Gag KK10 response in the control of HIV but also suggest a previously unrecognized role played by the subdominant Pol-specific KY9 response in HLA-B 2705-mediated control of HIV and that the recognition of HIV-infected cells by CD8(+) T cells early in the viral life cycle may be important for viral containment in HIV-infected individuals.

In order to explore the mechanisms of inflammatory skin disorders, we established two methods of expanding skin-derived lymphocytes, one using high levels of interleukin (IL)-2 and IL-4 (method A) and the other using low levels of cytokines and anti-CD3/CD28 microbeads (method B). Both methods provide advantages for functional studies. With either of these two, we could obtain more than 10(7) cells/ from a 3 mm skin biopsy in 21 days from 23 out of 26 biopsies of various skin diseases. The relevance of these cells was confirmed by shifted T-cell receptor beta chain variable region (TCR-Vbeta) repertoire and antigen-dependent proliferation in antigen-driven skin disorders. The propagation of skin-resident lymphocytes, seen especially in method A, seems to be mediated by a functional defect of regulatory T cells residing in skin sequentially expanding under the conditions of our methods., In order to explore the mechanisms of inflammatory skin disorders, we established two methods of expanding skin-derived lymphocytes, one using high levels of interleukin (IL)-2 and IL-4 (method A) and the other using low levels of cytokines and anti-CD3/CD28 microbeads (method B). Both methods provide advantages for functional studies. With either of these two, we could obtain more than 10(7) cells/ from a 3 mm skin biopsy in 21 days from 23 out of 26 biopsies of various skin diseases. The relevance of these cells was confirmed by shifted T-cell receptor beta chain variable region (TCR-Vbeta) repertoire and antigen-dependent proliferation in antigen-driven skin disorders. The propagation of skin-resident lymphocytes, seen especially in method A, seems to be mediated by a functional defect of regulatory T cells residing in skin sequentially expanding under the conditions of our methods.

In order to explore the mechanisms of inflammatory skin disorders, we established two methods of expanding skin-derived lymphocytes, one using high levels of interleukin (IL)-2 and IL-4 (method A) and the other using low levels of cytokines and anti-CD3/CD28 microbeads (method B). Both methods provide advantages for functional studies. With either of these two, we could obtain more than 10(7) cells/ from a 3 mm skin biopsy in 21 days from 23 out of 26 biopsies of various skin diseases. The relevance of these cells was confirmed by shifted T-cell receptor beta chain variable region (TCR-Vbeta) repertoire and antigen-dependent proliferation in antigen-driven skin disorders. The propagation of skin-resident lymphocytes, seen especially in method A, seems to be mediated by a functional defect of regulatory T cells residing in skin sequentially expanding under the conditions of our methods., In order to explore the mechanisms of inflammatory skin disorders, we established two methods of expanding skin-derived lymphocytes, one using high levels of interleukin (IL)-2 and IL-4 (method A) and the other using low levels of cytokines and anti-CD3/CD28 microbeads (method B). Both methods provide advantages for functional studies. With either of these two, we could obtain more than 10(7) cells/ from a 3 mm skin biopsy in 21 days from 23 out of 26 biopsies of various skin diseases. The relevance of these cells was confirmed by shifted T-cell receptor beta chain variable region (TCR-Vbeta) repertoire and antigen-dependent proliferation in antigen-driven skin disorders. The propagation of skin-resident lymphocytes, seen especially in method A, seems to be mediated by a functional defect of regulatory T cells residing in skin sequentially expanding under the conditions of our methods.

Goniothalamin is a biologically active styrylpyrone derivative isolated from various Goniothalamus sp., belonging to the Annonacae family. This plant extract has been reported to be cytotoxic towards several tumor cell lines such as pancreas carcinoma (PANC-1), gastric carcinoma (HGC-27) and breast carcinoma (MCF-7). The purpose of this study was to examine and characterize the in vitro cytotoxicity effect of goniothalamin on the human hepatocellular carcinoma HepG2 cells and normal liver Chang cells and also to study the morphological and biochemical changes of goniothalamin-treated HepG2 and Chang cells. Goniothalamin (2.3 -150 μM; 24, 48 and 72 hours) treatment to HepG2 and Chang cells resulted in a dose and time dependent inhibition of cell growth as assessed by MTT and LDH assays. The data suggest that goniothalamin selectively inhibits HepG2 cells (IC50 of MTT= 4.6(±0.23) μM; IC50 of LDH= 5.20(±0.01) μM for 72 hours) with less inhibition of growth in Chang cells (IC50 of MTT= 35.0(±0.09) μM; IC50 of LDH= 32.5(± 0.04) μM for 72 hours. The cytotoxic activity of goniothalamin on HepG2 cells was confirmed by Trypan blue dye exclusion assay. Goniothalamin reduced the number of viable cells (non-stained) associated with an increase on the number of non-viable cells (stained) and the Viability Indexes were 52 ± 1.73% for HepG2 cells and 62 ± 4.36% for Chang cells at IC50 after 72 hours. Cells were exposed to goniothalamin at lowest concentration (2.3 μM), IC50 (of MTT results), and highest concentration (150 μM) for 24, 48, or 72 hours and then examined for effects on cell cycle (using the flow cytometry) or proliferation (using the BrdU ELISA assay). The cytotoxic activity of goniothalamin was related to the inhibition of DNA synthesis, as revealed by the reduction of BrdU incorporation. At 72 hours with the lowest goniothalamin concentration of 2.3 μM, the normal liver Chang cells retained 97.6% of control proliferation while the liver cancer HepG2 cells were reduc

Goniothalamin is a biologically active styrylpyrone derivative isolated from various Goniothalamus sp., belonging to the Annonacae family. This plant extract has been reported to be cytotoxic towards several tumor cell lines such as pancreas carcinoma (PANC-1), gastric carcinoma (HGC-27) and breast carcinoma (MCF-7). The purpose of this study was to examine and characterize the in vitro cytotoxicity effect of goniothalamin on the human hepatocellular carcinoma HepG2 cells and normal liver Chang cells and also to study the morphological and biochemical changes of goniothalamin-treated HepG2 and Chang cells. Goniothalamin (2.3 -150 μM; 24, 48 and 72 hours) treatment to HepG2 and Chang cells resulted in a dose and time dependent inhibition of cell growth as assessed by MTT and LDH assays. The data suggest that goniothalamin selectively inhibits HepG2 cells (IC50 of MTT= 4.6(±0.23) μM; IC50 of LDH= 5.20(±0.01) μM for 72 hours) with less inhibition of growth in Chang cells (IC50 of MTT= 35.0(±0.09) μM; IC50 of LDH= 32.5(± 0.04) μM for 72 hours. The cytotoxic activity of goniothalamin on HepG2 cells was confirmed by Trypan blue dye exclusion assay. Goniothalamin reduced the number of viable cells (non-stained) associated with an increase on the number of non-viable cells (stained) and the Viability Indexes were 52 ± 1.73% for HepG2 cells and 62 ± 4.36% for Chang cells at IC50 after 72 hours. Cells were exposed to goniothalamin at lowest concentration (2.3 μM), IC50 (of MTT results), and highest concentration (150 μM) for 24, 48, or 72 hours and then examined for effects on cell cycle (using the flow cytometry) or proliferation (using the BrdU ELISA assay). The cytotoxic activity of goniothalamin was related to the inhibition of DNA synthesis, as revealed by the reduction of BrdU incorporation. At 72 hours with the lowest goniothalamin concentration of 2.3 μM, the normal liver Chang cells retained 97.6% of control proliferation while the liver cancer HepG2 cells were reduc

We recently reported that differentiation of CD8(+) T cells from the naïve to the effector state involves the upregulation of glucose-dependent metabolism. Glucose deprivation or inhibition of glycolysis by 2-deoxy-D-glucose (2-DG) selectively inhibited production of IFN-gamma but not of IL-2. To determine a more global role of glucose metabolism on effector T-cell function, we performed gene array analysis on CD8(+) effector T cells stimulated in the presence or absence of 2-DG. We observed that expression of only 10% of genes induced by TCR/CD28 signaling was inhibited by 2-DG. Among these were genes for key cytokines, cell cycle molecules, and cytotoxic granule proteins. Consistent with these results, production of IFN-gamma and GM-CSF, cell cycle progression, upregulation of cyclin D2 protein, cytolytic activity, and upregulation of granzyme B protein and also conjugate formation were exquisitely glucose-dependent. In contrast to glucose, oxygen was little utilized by CD8(+) effector T cells, and relative oxygen deprivation did not inhibit these CTL functional properties. Our results indicate a particularly critical role for glucose in regulating specific effector functions of CD8(+) T cells and have implications for the maintenance of the effector phase of cellular immune responses in target tissue microenvironments such as a solid tumor., Journal Article, Research Support, N.I.H. Extramural, FLWIN, info:eu-repo/semantics/published

Despite the increasing number of immunotherapeutic strategies for the treatment of cancer, most approaches have failed to correlate the induction of an anti-tumor immune response with therapeutic efficacy. We therefore took advantage of a successful vaccination strategy-combining dendritic cells and irradiated GM-CSF secreting tumor cells-to compare the immune response induced against 9L gliosarcoma tumors in cured rats versus those with progressively growing tumors. At the systemic level, the tumor specific cytotoxic responses were quite heterogeneous in uncured vaccinated rats, and were surprisingly often high in animals with rapidly-growing tumors. IFN-gamma secretion by activated splenic T cells was more discriminative as the CD4+ T cell-mediated production was weak in uncured rats whereas high in cured ones. At the tumor level, regressing tumors were strongly infiltrated by CD8+ T cells, which demonstrated lytic capacities as high as their splenic counterparts. In contrast, progressing tumors were weakly infiltrated by T cells showing impaired cytotoxic activities. Proportionately to the T cell infiltrate, the expression of Foxp3 was increased in progressive tumors suggesting inhibition by regulatory T cells. In conclusion, the main difference between cured and uncured vaccinated animals does not depend directly upon the induction of systemic cytotoxic responses. Rather the persistence of higher CD4+ Th1 responses, a high intratumoral recruitment of functional CD8+ T cells, and a low proportion of regulatory T cells correlate with tumor rejection., Journal Article, Research Support, Non-U.S. Gov't, info:eu-repo/semantics/published

Despite the increasing number of immunotherapeutic strategies for the treatment of cancer, most approaches have failed to correlate the induction of an anti-tumor immune response with therapeutic efficacy. We therefore took advantage of a successful vaccination strategy-combining dendritic cells and irradiated GM-CSF secreting tumor cells-to compare the immune response induced against 9L gliosarcoma tumors in cured rats versus those with progressively growing tumors. At the systemic level, the tumor specific cytotoxic responses were quite heterogeneous in uncured vaccinated rats, and were surprisingly often high in animals with rapidly-growing tumors. IFN-gamma secretion by activated splenic T cells was more discriminative as the CD4+ T cell-mediated production was weak in uncured rats whereas high in cured ones. At the tumor level, regressing tumors were strongly infiltrated by CD8+ T cells, which demonstrated lytic capacities as high as their splenic counterparts. In contrast, progressing tumors were weakly infiltrated by T cells showing impaired cytotoxic activities. Proportionately to the T cell infiltrate, the expression of Foxp3 was increased in progressive tumors suggesting inhibition by regulatory T cells. In conclusion, the main difference between cured and uncured vaccinated animals does not depend directly upon the induction of systemic cytotoxic responses. Rather the persistence of higher CD4+ Th1 responses, a high intratumoral recruitment of functional CD8+ T cells, and a low proportion of regulatory T cells correlate with tumor rejection., Journal Article, Research Support, Non-U.S. Gov't, info:eu-repo/semantics/published

We recently reported that differentiation of CD8(+) T cells from the naïve to the effector state involves the upregulation of glucose-dependent metabolism. Glucose deprivation or inhibition of glycolysis by 2-deoxy-D-glucose (2-DG) selectively inhibited production of IFN-gamma but not of IL-2. To determine a more global role of glucose metabolism on effector T-cell function, we performed gene array analysis on CD8(+) effector T cells stimulated in the presence or absence of 2-DG. We observed that expression of only 10% of genes induced by TCR/CD28 signaling was inhibited by 2-DG. Among these were genes for key cytokines, cell cycle molecules, and cytotoxic granule proteins. Consistent with these results, production of IFN-gamma and GM-CSF, cell cycle progression, upregulation of cyclin D2 protein, cytolytic activity, and upregulation of granzyme B protein and also conjugate formation were exquisitely glucose-dependent. In contrast to glucose, oxygen was little utilized by CD8(+) effector T cells, and relative oxygen deprivation did not inhibit these CTL functional properties. Our results indicate a particularly critical role for glucose in regulating specific effector functions of CD8(+) T cells and have implications for the maintenance of the effector phase of cellular immune responses in target tissue microenvironments such as a solid tumor., Journal Article, Research Support, N.I.H. Extramural, FLWIN, info:eu-repo/semantics/published

Background: Until now, cytokine-induced killer (CIK) cells were assumed to be part of the type I natural killer T (NKT) cell population, but it was not yet investigated if this is correct. Methods: For analysis, CIK cells were generated by various culture conditions. Human type I NKT cells express a T cell receptor (TCR) composed of an invariant Valpha24-JalphaQ chain combined with one of several Vbeta chains. The Valpha24 is a reliable marker for the presence of these TCRs. Results: While comparing cultures stimulated with different substances, we observed the lack of any Valpha24 on the surface of CIK culture cells. Conclusion: We conclude that CIK cells do not belong to the type I NKT cells., Hintergrund: Bis jetzt wurde angenommen, dass Zytokin-induzierte Killer(CIK)-Zellen Teil einer Typ I natürliche Killer-T(NKT)-Zellpopulation sind, aber bisher fehlten die Untersuchungen, die dies bestätigten. Methoden: Zur Analyse wurden CIK-Zellen unter verschiedenen Kulturbedingungen hergestellt. Humane Typ I NKT-Zellen exprimieren einen T-Zellrezeptor (TCR), der zusammengesetzt ist mit einer invariaten Valpha24-JalphaQ-Kette kombiniert mit einer von verschiedenen Vbeta-Ketten. Valpha24 kann als zuverlässiger Marker für das Vorhandensein von diesen TCRs verwendet werden. Ergebnisse: Beim Vergleich von mehreren CIK-Zellkulturen fanden wir keine Valpha24-Expression auf der Oberfläche von CIK-Zellen. Schlussfolgerung: Wir schlussfolgern, dass CIK-Zellen nicht zum Typ I NKT-Zellen gehören.

Interleukin 9 (IL-9) is a T-cell derived factor preferentially expressed by CD4+ Th2 cells and it has been characterized both in human and murine systems. It is a pleiotropic cytokine with multiple functions on cells of the lymphoid, myeloid and mast cell lineages, as well as on lung epithelial cells. Other activities described for IL-9 support its contribution to asthma and its important role in helminthic infections, where a Th2 response can be protective and IL-9 enhances resistance or is responsible for elimination of the nematode. Nevertheless, until recently there were no studies on its role in bacterial infections in man. We have demonstrated that cytokines can modulate the specific cytotoxicity generation in peripheral blood mononuclear cells from leprosy patients and normal controls. In the present report we studied the effect of IL-9 in this experimental model. Our results indicate that IL-9 can counteract the negative effect mediated by IL-4 on the generation of M. leprae-induced cytotoxic T lymphocytes. Moreover, it can increase this lytic activity in controls and enhance the stimulatory effect of IL-2 or IL-6 in cells from leprosy patients and controls. IL-9 is also able to revert the inhibitory effect of IL-10 and IL-13 on the M. leprae-induced cytotoxic activity. Although the exact mechanism of action of IL-9 remains to be determined, interferon gamma seems to be required for the effect of IL-9 in this experimental model. These data suggest that IL-9 may have an atypical Th2 behaviour and play a role in the modulation of the immune response to mycobacterial infections.

N/D

Objective: Therapeutic vaccination with dendritic cells (DC) showed promising results in first clinical trials in cases of metastatic renal cell carcinoma (RCC). Human telomerase reverse transcriptase (hTERT) could be a potential target because it is detectable in more than 85% of human tumors including RCC.Design: 10 patients with progressive metastatic RCC were enrolled in a clinical phase I/II trial using DC pulsed with hTERT-peptide. Beside toxicity and feasibility aspects, a complex immune monitoring including in vitro data were evaluated. In addition to detection of tumor-specific effector cells we investigated their functionality like IFN-gamma secretion and cytotoxic activity against tumor cells.Results: The vaccine was well tolerated. Two patients showed a mixed response (MR) and one patient a stable disease (SD). Interestingly, responders showed cytotoxic activity already before start of therapy and there was a significant increase in cytotoxic activity of effector cells from all responders (SD and MR patients) after the first vaccination. In contrast non-responders showed no cytotoxic activity before and during treatment. Therefore, cytotoxic activity might be used as a predictive marker in the future. Tetramer staining detected higher amounts of tumor-specific cytotoxic cells in responding patients compared to non-responders. Also, responders possessed increasing amounts of IFN-gamma producing immunological effector cells.Conclusion: Telomerase-pulsed DC could enhance a tumor-specific immune response against RCC., Ziel: Therapeutische Impfungen mit Antigen-beladenen dendritischen Zellen (DC) zeigten in ersten klinischen Versuchen bei Patienten mit metastasierendem Nierenzellkarzinom (RCC) vielversprechende Ergebnisse. Die menschliche Telomerase-reverse-Transkriptase (hTERT) könnte ein mögliches Zielantigen sein, da sie in 85% aller menschlichen Tumore einschließlich dem Nierenzellkarzinom nachweisbar ist.Methodik: 10 Patienten mit fortschreitend metastasierendem RCC wurden in einer klinischen Phase I/II-Studie untersucht, nachdem sie mehrere intratumorale Impfungen aus hTERT-beladenen autologen DCs erhalten haben. Neben Überprüfung der Verträglichkeit wurden verschiedenste in vitro Analysen durchgeführt, die Aussagen über den Immunstatus der Patienten geben sollen. Hierbei wurde sowohl nach tumor-spezifischen Effektorzellen geschaut, als auch deren Funktionalität in Form von IFN-gamma Sekretion oder Zytotoxizität gegenüber Tumorzellen untersucht.Ergebnisse: Die Impfungen wurden von allen Patienten gut vertragen. Zwei Patienten zeigten eine Mischantwort (MR) mit Rückbildung der punktierten Metastase und ein Patient zeigte eine Stabilisierung (SD) mit unverändertem Krankheitsverlauf. Erstaunlicherweise konnte bei den ansprechenden Patienten schon vor Studienbeginn eine Zytotoxizität von Effektorzellen nachgewiesen werden, die nach der 1. Impfung signifikant anstieg. Demgegenüber zeigten die nicht-ansprechenden Patienten vor, während und nach der Behandlung keine zytotoxische Aktivität gegenüber Tumorzellen. Folglich könnte die Zytotoxizität von Effektorzellen in Zukunft als Prognosemarker verwendet werden. Die ansprechenden Patienten besaßen im Vergleich zu den nicht-ansprechenden Patienten eine höhere Anzahl an Tumor-spezifischen zytotoxischen Zellen sowie IFN-gamma produzierenden Effektorzellen.Schlussfolgerung: Wir konnten zeigen, dass eine Impfung mit Telomerase-beladenen autologen DCs eine in geringem Ausmaß vorhandene Tumor-spezifische Immunantwort signifikant verstärken

"Cancer-germline" genes such as those of the MAGE family are expressed in many tumors and in male germline cells, but are silent in other normal tissues. They encode tumor specific antigens that are used in cancer immunotherapy trials. MAGE-4 antigens represent promising targets for cancer immunotherapy because gene MAGE-4 is expressed in more than 50% of carcinomas of the esophagus, lung, bladder, and head and neck. To identify new MAGE-4 antigenic peptides, we have folded HLA-A*2402 soluble molecules with candidate peptide NYKRCFPVI, which corresponds to amino acids 143 to151 of the MAGE-4 protein. A24/MAGE-4 multimers were used to isolate a cytolytic T cell clone that recognized the MAGE-4 peptide from the blood cells of a donor without cancer. This clone lysed specifically A24 carcinoma cells expressing MAGE-4. The antigenic peptide is processed more efficiently in tumor cells pre-treated with IFN-gamma. This MAGE-4 peptide could represent an interesting target for immunotherapy because it is presented by HLA-A24 molecules, which are widely expressed in different ethnic groups.

CD8-positive T lymphocytes recognize peptides that are usually derived from the degradation of cellular proteins and are presented by class I molecules of the major histocompatibility complex. Here we describe a human minor histocompatibility antigen created by a polymorphism in the SP110 nuclear phosphoprotein gene. The antigenic peptide comprises two noncontiguous SP110 peptide segments spliced together in reverse order to that in which they occur in the predicted SP110 protein. The antigenic peptide could be produced in vitro by incubation of precursor peptides with highly purified 20S proteasomes. Cutting and splicing probably occur within the proteasome by transpeptidation.

BACKGROUND AND OBJECTIVES: Anaplastic lymphoma kinase (ALK) oncogenic fusion proteins, expressed in about 60% of anaplastic large cell lymphomas (ALCL), are tumor-specific molecular targets for such a malignancy. One of the promising ALK-targeted therapeutic options is cancer vaccination. In this study, we investigate whether ALK is a tumor-associated antigen suitable for immune interventions. DESIGN AND METHODS: The frequency and the functional phenotype of the anti-ALK CD8 precursor repertoire in freshly isolated peripheral blood mononuclear cells (PBMC) from healthy donors and ALK-positive patients were determined by major histocompatibility complex (MHC)/tetrameric analyses. The anti-ALK secondary immune responses were evaluated as PBMC-specific interferon (INF-gamma) release by ELISPOT. In addition, the ability of the anti-ALK immune response to specifically lyse ALK-positive lymphoma cells was investigated by in vitro stimulation with ALK-derived peptide p280-89. RESULTS: Tetrameric MHC/peptide complexes revealed high frequencies of CD8/ALK-tetramer-positive cells both in patients and in healthy individuals. However, the functional phenotype of the CD8/ALK-tetramer-positive lymphocytes showed the presence of effector and memory T lymphocytes only in patients. The anti-ALK cytotoxic T lymphocytes (CTL) of patients, but not healthy donors, displayed thresholds of activation comparable to those of CTL precursors of a recall antigen (influenza virus). A polyclonal ALK-specific tumor-reactive T-cell line was isolated from patients' peripheral blood lymphocytes. INTERPRETATION AND CONCLUSIONS: The presence of an anti-ALK effector/memory lymphocyte population in the peripheral blood of ALK-positive patients indicates an in vivo antigenic challenge. Thus, ALK is a lymphoma-associated antigen suitable for immune interventions. The high number of anti-ALK memory CD8 T cells present in patients' PBMC may represent a valid source of activated CTL suitable for cancer cell

To explore the potential of using non-human coronaviruses for cancer therapy, we first established their ability to kill human tumor cells. We found that the feline infectious peritonitis virus (FIPV) and a felinized murine hepatitis virus (fMHV), both normally incapable of infecting human cells, could rapidly and effectively kill human cancer cells artificially expressing the feline coronavirus receptor aminopeptidase N. Also 3-D multilayer tumor spheroids established from such cells were effectively eradicated. Next, we investigated whether FIPV and fMHV could be targeted to human cancer cells by constructing a bispecific single-chain antibody directed on the one hand against the feline coronavirus spike protein--responsible for receptor binding and subsequent cell entry through virus-cell membrane fusion--and on the other hand against the human epidermal growth factor receptor (EGFR). The targeting antibody mediated specific infection of EGFR-expressing human cancer cells by both coronaviruses. Furthermore, in the presence of the targeting antibody, infected cancer cells formed syncytia typical of productive coronavirus infection. By their potent cytotoxicity, the selective targeting of non-human coronaviruses to human cancer cells provides a rationale for further investigations into the use of these viruses as anticancer agents.

A panel of autologous cytolytic T lymphocyte (CTL) clones have been isolated from blood lymphocytes of a melanoma patient after in vitro stimulation with autologous tumor cells. We previously reported the molecular definition of three distinct antigens recognized by some of these CTL clones. We describe here, the identification of a fourth antigenic peptide expressed by this melanoma line and recognized by a CTL clone restricted by HLA-B*3503. The antigenic peptide, which is nine-amino acid long, has the sequence LPHSSSHWL and is derived from melanocyte differentiation antigen gp100. As HLA-B35 is one of the most frequent HLA-B alleles, being present in 20% of the Caucasian individuals, this peptide may be a good target for peptide-based immunotherapy of melanoma.

After vaccination of melanoma patients with MAGE antigens, we observed that even in the few patients showing tumor regression, the frequency of anti-vaccine T cells in the blood was often either undetectable or <10(-5) of CD8 T cells. This frequency being arguably too low for these cells to be sole effectors of rejection, we reexamined the contribution of T cells recognizing other tumor antigens. The presence of such antitumor T cells in melanoma patients has been widely reported. To begin assessing their contribution to vaccine-induced rejection, we evaluated their blood frequency in five vaccinated patients. The antitumor cytotoxic T lymphocyte (CTL) precursors ranged from 10(-4) to 3 x 10(-3), which is 10-10,000 times higher than the anti-vaccine CTL in the same patient. High frequencies were also observed before vaccination. In a patient showing nearly complete regression after vaccination with a MAGE-3 antigen, we observed a remarkably focused antitumoral response. A majority of CTL precursors (CTLp's) recognized antigens encoded by MAGE-C2, another cancer-germline gene. Others recognized gp100 antigens. CTLp's recognizing MAGE-C2 and gp100 antigens were already present before vaccination, but new clonotypes appeared afterwards. These results suggest that a spontaneous antitumor T cell response, which has become ineffective, can be reawakened by vaccination and contribute to tumor rejection. This notion is reinforced by the frequencies of anti-vaccine and antitumor CTLs observed inside metastases, as presented by Lurquin et al. (Lurquin, C., B. Lethe, V. Corbiere, I. Theate, N. van Baren, P.G. Coulie, and T. Boon. 2004. J. Exp. Med. 201:249-257).

A major barrier to successful antitumor vaccination is tolerance of high-avidity T cells specific to tumor antigens. In keeping with this notion, HER-2/neu (neu)-targeted vaccines, which raise strong CD8(+) T cell responses to a dominant peptide (RNEU(420-429)) in WT FVB/N mice and protect them from a neu-expressing tumor challenge, fail to do so in MMTV-neu (neu-N) transgenic mice. However, treatment of neu-N mice with vaccine and cyclophosphamide-containing chemotherapy resulted in tumor protection in a proportion of mice. This effect was specifically abrogated by the transfer of neu-N-derived CD4(+)CD25(+) T cells. RNEU(420-429)-specific CD8(+) T cells were identified only in neu-N mice given vaccine and cyclophosphamide chemotherapy which rejected tumor challenge. Tetramer-binding studies demonstrated that cyclophosphamide pretreatment allowed the activation of high-avidity RNEU(420-429)-specific CD8(+) T cells comparable to those generated from vaccinated FVB/N mice. Cyclophosphamide seemed to inhibit regulatory T (T reg) cells by selectively depleting the cycling population of CD4(+)CD25(+) T cells in neu-N mice. These findings demonstrate that neu-N mice possess latent pools of high-avidity neu-specific CD8(+) T cells that can be recruited to produce an effective antitumor response if T reg cells are blocked or removed by using approaches such as administration of cyclophosphamide before vaccination.

This review builds on evidence that cell-mediated immune responses to bacteria, viruses, parasites, and tumors are an integration of conventional and unconventional T-cell activities. Whereas conventional T cells provide clonal antigen-specific responses, unconventional T cells profoundly regulate conventional T cells, often suppressing their activities such that immunopathology is limited. By extrapolation, immunopathologies and inflammatory diseases may reflect defects in regulation by unconventional T cells. To explore the function of unconventional T cells, several extensive gene expression analyses have been undertaken. These studies are reviewed in some detail, with emphasis on the mechanisms by which unconventional T cells may exert their regulatory functions. Highlighting the fundamental nature of T-cell integration, we also review emerging data that the development of conventional and unconventional T cells is also highly integrated., Journal Article, Research Support, N.I.H. Extramural, Research Support, Non-U.S. Gov't, Research Support, U.S. Gov't, P.H.S., Review, info:eu-repo/semantics/published

This review builds on evidence that cell-mediated immune responses to bacteria, viruses, parasites, and tumors are an integration of conventional and unconventional T-cell activities. Whereas conventional T cells provide clonal antigen-specific responses, unconventional T cells profoundly regulate conventional T cells, often suppressing their activities such that immunopathology is limited. By extrapolation, immunopathologies and inflammatory diseases may reflect defects in regulation by unconventional T cells. To explore the function of unconventional T cells, several extensive gene expression analyses have been undertaken. These studies are reviewed in some detail, with emphasis on the mechanisms by which unconventional T cells may exert their regulatory functions. Highlighting the fundamental nature of T-cell integration, we also review emerging data that the development of conventional and unconventional T cells is also highly integrated., Journal Article, Research Support, N.I.H. Extramural, Research Support, Non-U.S. Gov't, Research Support, U.S. Gov't, P.H.S., Review, info:eu-repo/semantics/published

The cancer-germline gene MAGE-3 codes for tumor-specific antigens recognized on many tumors by T lymphocytes. A MAGE-3 antigen presented by HLA-A1 has been used in several vaccination trials on metastatic melanoma patients. Only a small minority of patients have shown evidence of tumor regression. Attempts to correlate the tumor rejections with the cytotoxic T lymphocyte (CTL) response against the vaccine have been hampered by the low level of these responses. In noncancerous individuals, the frequency of the T cell precursors against antigen MAGE-3.A1 is approximately 4 x 10(-7) CD8 T cells. The diversity of the T cell receptor repertoire of these anti-MAGE-3.A1 precursors was analyzed in one individual. The results indicate that it is very likely that the repertoire comprises >100 clonotypes. On this basis, it is possible to use not only the frequency of CTL precursors in the blood but also the presence of dominant clonotypes to ascertain in patients the existence of anti-MAGE-3.A1 responses as low as 10(-6) of CD8. With this approach, we observed a correlation between tumor regression and anti-MAGE-3.A1 CTL responses in patients vaccinated with a recombinant virus encoding the antigen and also in patients vaccinated with peptide-pulsed dendritic cells. In contrast, for patients showing tumor regression after vaccination with peptide alone, CTL responses were almost never observed. It is possible that even those CTL responses that are below our present detection level can trigger a sequence of events that leads to tumor regression.

Antigens encoded by MAGE genes are of particular interest for cancer immunotherapy because they are tumor specific and shared by tumors of different histological types. Several clinical trials are in progress with MAGE peptides, proteins, recombinant poxviruses, and dendritic cells (DC) pulsed with peptides or proteins. The use of gene-modified DC would offer the major advantage of a long-lasting expression of the transgene and a large array of antigenic peptides that fit into the different HLA molecules of the patient. In this study, we tested the ability of gene-modified DC to prime rare Ag-specific T cells, and we identified a new antigenic peptide of clinical interest. CD8(+) T lymphocytes from an individual without cancer were stimulated with monocyte-derived DC, which were infected with a second-generation lentiviral vector encoding MAGE-3. A CTL clone was isolated that recognized peptide EGDCAPEEK presented by HLA-Cw7 molecules, which are expressed by >40% of Caucasians. Interestingly, this new tumor-specific antigenic peptide corresponds to position 212-220 of MAGE-2, -3, -6, and -12. HLA-Cw7 tumor cell lines expressing one of these MAGE genes were lysed by the CTL, indicating that the peptide is efficiently processed in tumor cells and can therefore be used as target for antitumoral vaccination. The risk of tumor escape due to appearance of Ag-loss variants should be reduced by the fact that the peptide is encoded by several MAGE genes.

Hepatic NK cells are more cytotoxic than blood NK cells against tumor cells. To understand the basis of this difference in cytotoxicity we analyzed RNA derived from freshly isolated rat blood and hepatic NK cells [high-density (HD) and low-density subpopulations] by high-density oligonucleotide arrays (Affymetrix), containing about 9,000 genes and expressed sequence tags. IL-2-treated blood NK (A-NK) cells and IL-2-treated hepatic HD cells were used as a reference of NK cell activation. About 150 genes and expressed sequence tags were differentially expressed between hepatic and blood NK cells. Surprisingly, more than half of the increased expressed genes in hepatic NK cells were not increased in A-NK cells. Differentially expressed genes like the stem cell factor receptor c-kit and the chemokine receptor CCR5 can contribute to the homing and differentiation of hepatic NK cells in the liver sinusoids. Several of the differentially expressed genes can possibly contribute to the enhanced cytotoxic activity of hepatic NK cells: cell membrane receptors like NKG2D, NKG2C, CD94, ecto-ATPase; signaling molecules like phosphatidylinositol 3-kinase; granule-associated effector molecules like granzymes and defensin NP3. Moreover, it appears that redirection of cytotoxic granules and increase in intracellular Ca2+ are convergence points of several of these genes., Journal Article, FLWIN, info:eu-repo/semantics/published

Dendritic cells (DCs) play a predominant role in activation of natural killer (NK) cells that exert their functions against pathogen-infected and tumor cells. Here, we used a murine model to investigate the molecular mechanisms responsible for this process. Two soluble molecules produced by bacterially activated myeloid DCs are required for optimal priming of NK cells. Type I interferons (IFNs) promote the cytotoxic functions of NK cells. IL-2 is necessary both in vitro and in vivo for the efficient production of IFNgamma, which has an important antimetastatic and antibacterial function. These findings provide new information about the mechanisms that mediate DC-NK cell interactions and define a novel and fundamental role for IL-2 in innate immunity

Hepatic NK cells are more cytotoxic than blood NK cells against tumor cells. To understand the basis of this difference in cytotoxicity we analyzed RNA derived from freshly isolated rat blood and hepatic NK cells [high-density (HD) and low-density subpopulations] by high-density oligonucleotide arrays (Affymetrix), containing about 9,000 genes and expressed sequence tags. IL-2-treated blood NK (A-NK) cells and IL-2-treated hepatic HD cells were used as a reference of NK cell activation. About 150 genes and expressed sequence tags were differentially expressed between hepatic and blood NK cells. Surprisingly, more than half of the increased expressed genes in hepatic NK cells were not increased in A-NK cells. Differentially expressed genes like the stem cell factor receptor c-kit and the chemokine receptor CCR5 can contribute to the homing and differentiation of hepatic NK cells in the liver sinusoids. Several of the differentially expressed genes can possibly contribute to the enhanced cytotoxic activity of hepatic NK cells: cell membrane receptors like NKG2D, NKG2C, CD94, ecto-ATPase; signaling molecules like phosphatidylinositol 3-kinase; granule-associated effector molecules like granzymes and defensin NP3. Moreover, it appears that redirection of cytotoxic granules and increase in intracellular Ca2+ are convergence points of several of these genes., Journal Article, FLWIN, info:eu-repo/semantics/published

"Cancer-germline" genes such as those of the MAGE family are expressed in many tumors and in male germline cells, but are silent in normal tissues. They encode shared tumor-specific antigens, which have been used in therapeutic vaccination trials of cancer patients. MAGE-6 is expressed in more than 70% of metastatic melanomas and more than 50% of carcinomas of the lung, esophagus, bladder, and head and neck. We report here the identification of a new MAGE-6 antigenic peptide, which is recognized by a tumor-specific cytolytic T lymphocyte clone isolated from a melanoma patient. The peptide, ISGGPRISY, corresponds to positions 293 to 301 of the MAGE-6 protein sequence and is presented by HLA-Cw1601 molecules.

The specificity of recognition of pMHC complexes by T lymphocytes is determined by the V regions of the TCR alpha- and beta-chains. Recent experimental evidence has suggested that Ag-specific TCR repertoires may exhibit a more V alpha- than V beta-restricted usage. Whether V alpha usage is narrowed during immune responses to Ag or if, on the contrary, restricted V alpha usage is already defined at the early stages of TCR repertoire selection, however, has remained unexplored. Here, we analyzed V and CDR3 TCR regions of single circulating naive T cells specifically detected ex vivo and isolated with HLA-A2/melan-A peptide multimers. Similarly to what was previously observed for melan-A-specific Ag-experienced T cells, we found a relatively wide V beta usage, but a preferential V alpha 2.1 usage. Restricted V alpha 2.1 usage was also found among single CD8(+) A2/melan-A multimer(+) thymocytes, indicating that V alpha-restricted selection takes place in the thymus. V alpha 2.1 usage, however, was independent from functional avidity of Ag recognition. Thus, interaction of the pMHC complex with selected V alpha-chains contributes to set the broad Ag specificity, as underlined by preferential binding of A2/melan-A multimers to V alpha 2.1-bearing TCRs, whereas functional outcomes result from the sum of these with other interactions between pMHC complex and TCR.

Previous studies have suggested that defective immune responses in early life may be related to the immaturity of neonatal antigen-presenting cells. To test this hypothesis, we assessed the capacity of neonatal dendritic cells (DC) to prime and polarize in vitro human naive antigen-specific T cells. We report that mature cord blood DC efficiently prime an oligoclonal population of antigen-specific CD8 T cells, capable of cytolytic activity and IFN-gamma secretion. In contrast, cells primed by immature cord blood DC do not acquire cytolytic activity and secrete lower amounts of IFN-gamma. Upon priming by either immature or mature DC, neonatal T cells acquire markers of activation and differentiation towards effector-memory cells. Our results demonstrate that, if appropriately activated, neonatal DC can prime efficient cytotoxic T lymphocyte (CTL) responses. Furthermore, these findings have important implications for the development of vaccine strategies in early life and for the reconstitution of a functional CTL repertoire after bone marrow transplantation., Journal Article, Research Support, Non-U.S. Gov't, info:eu-repo/semantics/published

Transplantation tolerance induced by neonatal injection of semiallogeneic spleen cells is associated in several strain combinations with a pathological syndrome caused by Th2 differentiation of donor-specific CD4(+) T lymphocytes. We investigated the role of host CD8(+) T cells in the regulation of this Th2 pathology. IgE serum levels and eosinophilia significantly increased in BALB/c mice neonatally injected with (A/J x BALB/c)F(1) spleen cells when CD8(+) T cells were depleted by administration of anti-CD8 mAb or when beta(2)-microglobulin-deficient mice were used as recipients. In parallel, increased serum levels of IL-5 and IL-13 were measured in blood of tolerant CD8(+) T cell-deficient mice. Whereas neonatally injected mice were unable to generate anti-donor cytotoxic effectors, their CD8(+) T cells were as efficient as control CD8(+) T cells in reducing the severity of Th2 pathology and in restoring donor-specific cytotoxicity in vitro after in vivo transfer in beta(2)-microglobulin-deficient mice. Likewise, CD8(+) T cells from control and tolerant mice equally down-regulated the production of Th2 cytokines by donor-specific CD4(+) T cells in vitro. The regulatory activity of CD8(+) T cells depended on their secretion of IFN-gamma for the control of IL-5 production but not for IL-4 or IL-13. Finally, we found that CD8(+) T cells from 3-day-old mice were already able to down-regulate IL-4, IL-5, and IL-13 production by CD4(+) T cells. We conclude that regulatory CD8(+) T cells controlling Th2 responses are functional in early life and escape neonatal tolerization., Journal Article, Research Support, Non-U.S. Gov't, SCOPUS: ar.j, info:eu-repo/semantics/published

Natural killer (NK) cell differentiation from pluripotent CD34(+) human hematopoietic stem cells or oligopotent lymphoid progenitors has already been reported. In the present study, long-term cultures of the CD56(-)/CD34(-) myeloid-like adherent cell fraction (ACF) from umbilical cord blood (UCB), characterized by the expression of CD14(+) as well as other myeloid markers, were set up with flt3 ligand (FL) and interleukin-15 (IL-15). The UCB/ACF gradually expressed the CD56 marker, which reached fairly high levels (approximately 90% of the cells were CD56(+)) by day 15. FL plus IL-15-driven ACF/CD56(+) cells progressively expressed a mature NK functional program lysing both NK- and lymphokine-activate killer (LAK)-sensitive tumor targets and producing high levels of interferon-gamma (IFN-gamma), granulocyte-macrophage colony-stimulating factor, tumor necrosis factor alpha, and IL-10 upon stimulation with IL-12 and IL-18. Similar results were obtained when highly purified CD14(+) cells from UCB were cultured with FL and IL-15. In contrast, UCB/CD34(+) cells cultured under the same conditions showed a delayed expression of CD56 and behaved functionally differently in that they exhibited NK but not LAK cytotoxicity and produced significantly fewer cytokines. Kinetic studies on the phenotype of UCB/ACF or UCB/CD14(+) cells cultured in the presence of FL and IL-15 showed a rapid decrease in CD14 expression after day 5, which reached levels of zero by day 20. Approximately 60% of the CD56(+) derived from the UCB/ACF or the UCB/CD14(+) cells coexpressed CD14 by day 5. Taken together, our data support the role of CD14(+) myeloid-like cells within UCB as a novel progenitor for lymphoid NK cells., Journal Article, Research Support, Non-U.S. Gov't, info:eu-repo/semantics/published

Natural killer (NK) cell differentiation from pluripotent CD34(+) human hematopoietic stem cells or oligopotent lymphoid progenitors has already been reported. In the present study, long-term cultures of the CD56(-)/CD34(-) myeloid-like adherent cell fraction (ACF) from umbilical cord blood (UCB), characterized by the expression of CD14(+) as well as other myeloid markers, were set up with flt3 ligand (FL) and interleukin-15 (IL-15). The UCB/ACF gradually expressed the CD56 marker, which reached fairly high levels (approximately 90% of the cells were CD56(+)) by day 15. FL plus IL-15-driven ACF/CD56(+) cells progressively expressed a mature NK functional program lysing both NK- and lymphokine-activate killer (LAK)-sensitive tumor targets and producing high levels of interferon-gamma (IFN-gamma), granulocyte-macrophage colony-stimulating factor, tumor necrosis factor alpha, and IL-10 upon stimulation with IL-12 and IL-18. Similar results were obtained when highly purified CD14(+) cells from UCB were cultured with FL and IL-15. In contrast, UCB/CD34(+) cells cultured under the same conditions showed a delayed expression of CD56 and behaved functionally differently in that they exhibited NK but not LAK cytotoxicity and produced significantly fewer cytokines. Kinetic studies on the phenotype of UCB/ACF or UCB/CD14(+) cells cultured in the presence of FL and IL-15 showed a rapid decrease in CD14 expression after day 5, which reached levels of zero by day 20. Approximately 60% of the CD56(+) derived from the UCB/ACF or the UCB/CD14(+) cells coexpressed CD14 by day 5. Taken together, our data support the role of CD14(+) myeloid-like cells within UCB as a novel progenitor for lymphoid NK cells., Journal Article, Research Support, Non-U.S. Gov't, info:eu-repo/semantics/published

Previous studies have suggested that defective immune responses in early life may be related to the immaturity of neonatal antigen-presenting cells. To test this hypothesis, we assessed the capacity of neonatal dendritic cells (DC) to prime and polarize in vitro human naive antigen-specific T cells. We report that mature cord blood DC efficiently prime an oligoclonal population of antigen-specific CD8 T cells, capable of cytolytic activity and IFN-gamma secretion. In contrast, cells primed by immature cord blood DC do not acquire cytolytic activity and secrete lower amounts of IFN-gamma. Upon priming by either immature or mature DC, neonatal T cells acquire markers of activation and differentiation towards effector-memory cells. Our results demonstrate that, if appropriately activated, neonatal DC can prime efficient cytotoxic T lymphocyte (CTL) responses. Furthermore, these findings have important implications for the development of vaccine strategies in early life and for the reconstitution of a functional CTL repertoire after bone marrow transplantation., Journal Article, Research Support, Non-U.S. Gov't, info:eu-repo/semantics/published