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BACKGROUND & AIMS: Antiviral agents suppress hepatitis B virus (HBV) replication but do not clear the infection. A strong effector T-cell response is required to eradicate HBV, but this does not occur in patients with chronic infection. T cells might be directed toward virus-infected cells by expressing HBV-specific receptors, and thereby clear HBV and help to prevent development of liver cancer. In mice, we studied whether redirected T cells can engraft following adoptive transfer, without prior T-cell depletion, and whether the large amounts of circulating viral antigens inactivate the transferred T cells or lead to uncontrolled, immune-mediated damage. METHODS: CD8(+) T cells were isolated from mice and stimulated using an optimized protocol. Chimeric antigen receptors (CARs) that bind HBV envelope proteins (S-CAR) and activate T cells were expressed on the surface of cells using retroviral vectors. S-CAR-expressing CD8(+) T cells, which carried the marker CD45.1, were injected into CD45.2(+) HBV transgenic mice. We compared these mice with mice that received CD8(+) T cells induced by vaccination, cells that express a CAR without a proper signaling domain, or cells that express a CAR that does not bind HBV proteins (controls). RESULTS: CD8(+) T cells that expressed HBV-specific CARs recognized different HBV subtypes and were able to engraft and expand in immune-competent HBV transgenic mice. Following adoptive transfer, the S-CAR-expressing T cells localized to and functioned in the liver; they rapidly and efficiently controlled HBV replication, compared with controls, causing only transient liver damage. The large amount of circulating viral antigen did not impair or over-activate the S-CAR grafted T cells. CONCLUSION: T cells with a CAR specific for HBV envelop proteins localize to the livers of mice to reduce HBV replication, causing only transient liver damage. This immune-cell therapy might be developed for patients with chronic hepatitis B, regardless of their HLA-type.

More than 350 million people worldwide are persistently infected with human heptatitis B virus (HBV) and at risk to develop liver cirrhosis and hepatocellular carcinoma making long-term treatment necessary. While a vaccine is available and new antiviral drugs are being developed, elimination of persistently infected cells is still a major issue. Recent efforts in adoptive cell therapy are experimentally exploring immunotherapeutic elimination of HBV-infected cells by means of a biological attack with genetically engineered “designer” T cells.

Adoptive cellular therapy provides the promise of a potentially powerful general treatment for cancer. Although this is a complex and challenging field, there have been major advances in basic and translational research resulting in clinical trial activity that is now beginning to confirm this promise. However, these trials are also identifying new challenges and this review focuses on these clinical issues. For tumors such as melanoma, in which tumor-specific T cells can be readily identified and isolated, the adoptive transfer of "tumor-infiltrating lymphocytes'' (TILs) already appears to offer significant patient benefit and this approach now warrants further development. Genetically engineered T cells offer a means to endow peripheral blood T cells with antitumor activity and in principle these techniques could allow the treatment of a wide range of cancers. Genetic engineering also offers the means to endow T cells with new properties and enhanced functions. There have been clear proof-of-principle trials showing responses with T cell receptor (TCR)-engineered T cells and this can be built on with further development. By contrast, other trials have produced significant toxicity related to expression of target antigen on normal tissue, particularly with enhanced receptors. The challenge ahead lies in understanding how to achieve the balance between targeted antitumor immune responses while avoiding toxicity associated with on-target destruction of antigen-expressing normal tissues. Cellular therapy of cancer will need continued preclinical evaluation as well as carefully designed clinical trials addressing the various issues. For these challenges to be fully assessed, and for progression to a widely used, effective and safe therapy, development as cooperative groups is an appropriate way forward.

More than 350 million people worldwide are persistently infected with human heptatitis B virus (HBV) and at risk to develop liver cirrhosis and hepatocellular carcinoma making long-term treatment necessary. While a vaccine is available and new antiviral drugs are being developed, elimination of persistently infected cells is still a major issue. Recent efforts in adoptive cell therapy are experimentally exploring immunotherapeutic elimination of HBV-infected cells by means of a biological attack with genetically engineered "Designer" T cells.

Autocrine production of growth factors is thought to be an essential element in the development of hemopoietic tumors in vivo. Tumor-derived cell lines frequently show this capability in vitro. It is not understood how autonomous growth in vitro is maintained by lymphoid cell lines that are not of tumorigenic origin. We have previously established human B cell clones that proliferate in serum-free media with unlimited potential. However, the cells need a critical density for continuous growth. Culture supernatant conditioned by these cell lines sustained proliferation even in low density cultures. All B cell clones analyzed were found to secrete the cytokines IL-1 alpha, IL-6, TNF-alpha, and TNF-beta whereas no activity of IL-2, IL-4, low m. w.-B cell growth factor, CSF, or IFN-gamma was recorded. In low density cultures supplemented with rIL-1 alpha, +/- IL-6, +/- TNF-alpha, and +/- TNF-beta together, B cell proliferation is maintained to the same extent as with conditioned medium. Addition of anti-sense oligonucleotides directed to the mRNA of IL-1 alpha, IL-6, and TNF-alpha, respectively, resulted in growth arrest and cell death. This effect could be prevented by supplementation with these cytokines. Scatchard plot analyses and internalization studies revealed that the cells express on their surface high affinity receptors for IL-1 alpha, IL-6, and TNF, respectively, and internalize the cytokines from the supernatant. These results demonstrate that (i) autonomous growth of immortalized B cells is maintained by secretion and reinternalization of IL-1 alpha, IL-6, TNF-alpha, and TNF-beta, (ii) these cytokines act in a synergistic fashion, and (iii) autocrine growth stimulation of human B cells in vitro does not necessarily represent their tumorigenic potential in vivo.

Recombinant TCRs confer specificity to T cells and trigger their activation. Receptors with Ab-derived binding domains have the advantages of MHC-independent Ag recognition and of targeting a variety of chemically different molecules. We explored the impact of the position of a defined epitope within the target molecule on the efficacy of receptor-mediated T cell activation. T cells were grafted with recombinant immunoreceptors that recognize either the membrane distal N or the proximal A3 domain of carcinoembryonic Ag (CEA). Upon binding to isolated, solid-phase immobilized CEA, receptor-mediated T cell activation correlates with the binding efficiency, irrespectively, of the epitope position. Upon binding to CEA expressed on the cell membrane, in contrast, the A3 epitope mediates more efficiently T cell activation than the N epitope, although the N epitope is bound with higher affinity. The CEA N epitope when expressed in a more membrane proximal position, however, ac tivated receptor grafted T cells with higher efficiency than in the distal position. The position of the targeted epitope within the molecule obviously has major impact on the efficacy of T cell activation independently of the binding efficiency of the immunoreceptor.

Re-arrangement and expression of the immunoglobulin (Ig) genes in B cells occurs under an ordered developmental control. The sequential model of Ig light chain exclusion predicts that only after non-productive re-organization or deletion of both Ig kappa alleles would re-arrangement of Ig lambda gene segments occur. To prove this model, we asked whether expression of Ig lambda light chains is always associated with rearrangement and/or deletion of both Ig kappa alleles in human cells. Therefore, we established human diploid B-cell clones in vitro that produce Ig lambda light chains. Southern blot analysis of the Ig kappa alleles revealed that three Ig lambda expressing cell lines (out of six Ig lambda+ cell lines tested) harbour one Ig kappa allele in germline configuration. Furthermore, a 1.5 kb RNA derived from the germline Ig kappa locus was detected by Northern blot hybridizations. The results implicate that the mechanism of Ig light chain exclusion is not precisely sequential and that it does not necessarily need re-arrangement or deletion of both Ig kappa alleles as a prerequisite for Ig lambda light chain expression in human cells.

Human lymphocytes from peripheral blood were induced to proliferate indefinitely in vitro by transfection with cytoplasmic DNA isolated from transformed mouse L929 cells. Two cell lines analyzed proliferate in chemically defined, serum-free media without addition of cytokines. Using RIA and bioassays, the cells were found to secrete IL-1 alpha, IL-6, and TNF into the culture medium whereas no IL-2, IL-4, BCGF, CSF, or IFN-gamma were detected. Northern blot hybridizations revealed TNF alpha mRNA (1.5 kb) as well as TNF beta mRNA (1.4 kb) transcripts in RNA of the immortalized cells. Since the immortalized lymphoid cell lines neither form colonies in soft agar medium nor induce tumors after injection into immunodeficient nude mice, we suggest that these cytokines may be involved in autocrine growth stimulation of human lymphoid cell lines immortalized by transfection with cytoplasmic DNA from mouse L-cells.

Despite numerous studies conducted over the past decade, the exact role of the cannabinoid system in cancer development remains unclear. Though research has focused on two cannabinoid receptors (CB1, CB2) activated by most cannabinoids, CB2 holds greater attention due to its expression in cells of the immune system. In particular, cytokine-induced killer cells (CIKs), which are pivotal cytotoxic immunological effector cells, express a high-level of CB2 receptors. Herein, we sought to investigate whether inducing CIK cells with cannabidiol can enhance their cytotoxicity and if there are any possible counter effects in its downstream cascade of phosphorylated p38 and CREB using a pancreatic ductal adenocarcinoma cell line (PANC-1). Our results showed that IL-2 modulates primarily the expression of the CB2 receptor on CIK cells used during ex vivo CIK expansion. The autophagosomal-associated scaffold protein p62 was found to co-localize with CB2 receptors in CIK cells and the PANC-1 cell line. CIK cells showed a low level of intracellular phospho-p38 and, when stimulated with cannabidiol (CBD), a donor specific variability in phospho-CREB. CBD significantly decreases the viability of PANC-1 cells presumably by increasing the cytotoxicity of CIK cells. Taken together, in our preclinical in vitro study, we propose that a low effective dose of CBD is sufficient to stimulate the cytotoxic function of CIK without exerting any associated mediator. Thus, the combinatorial approach of non-psychoactive CBD and CIK cells appears to be safe and can be considered for a clinical perspective in pancreatic cancer.

Für die Diagnose und das Monitoring des Sézary Syndrome haben sich zwei hauptsächliche Herangehensweisen etabliert: die Immunophänotypisierung und PCR basierte T-Zell-Rezeptor (TCR)-Gen-Rearrangement Analyse. Die verminderte Expression von T-Zell-Antigenen auf im Blut zirkulierenden Lymphozyten ist beim Sézary Syndrom beschrieben, insbesondere der Antigene CD7 und CD26. Jedoch ist die Verteilung des genetisch definierten Tumorzellklons auf die CD7 und CD26 positiven bzw. negativen Subpopulationen bisher nicht untersucht worden. Aus diesem Grund etablierten wir eine qualitative sowie eine quantitative klonspezifische PCR und bestimmten die Verteilung der klonalen Zellen auf diese Subpopulationen. Diese Daten wurden anschließend in Beziehung zur Klinik und zur Prognose der Patienten gesetzt. Für jeden unserer fünf Sézary Syndrom Patienten wurde die Sequenz des klonalen TCR-gamma und TCR-beta Rearrangementes ermittelt. Es erfolgte eine durchflußzytometrische Analyse der PBMC hinsichtlich der CD7 und CD26 Expression. Anschließend wurde für jeden Fall eine klonspezifische qualitative und quantitative (real-time) PCR etabliert. Mit Hilfe dieser PCR untersuchten wir das Vorhandensein und die Frequenz klonaler Zellen in den sortierten Subpopulationen. Die FACS-Analyse ergab bei unseren Patienten im Vergleich zu den Kontrollen eine verminderte CD7 und CD26 Expression der Lymphozyten. In der qualitativen PCR konnten klonale Zellen sowohl in der CD7+ und CD7- Population gezeigt werden, gleiches gilt für die CD26 Populationen. Die quantitative PCR zeigte, dass der dominante T-Zell-Klon sowohl CD7+ als auch CD7- sein kann, wohingegen CD26- Tumorzellen bei weitem überwiegen. Hinsichtlich Klinik und Prognose deutete sich an, das ein CD7+ Tumorzellklon eine bessere Prognose für den Patienten bedeuten kann. Zusammenfassung: Die Tumorzellen des Sézary Syndrom zeigen einen CD3+CD7+CD26- sowie CD3+CD7-CD26- Phänotyp. Aus diesem Grund kann bei dieser Erkrankung die Tumorzelllast im Blut über die Bestimmung der CD3+CD26- Zellen erfolgen. Die Signifikanz eines CD7+ Tumorzellkolons in Bezug zur Prognose muß an einem größeren Patientenkollektiv überprüft werden., Introduction: For diagnosis and monitoring of the Sézary syndrome (SS) two crucial approaches are applied: immunophenotyping and PCR based T-cell receptor (TCR)-gene rearrangement analysis. The absence of T-cell antigens, in particular CD7 and CD26, on peripheral circulating tumor cells has been described in SS patients. However, the prevalence of the genetically identified malignant T-cell clone in CD7 and CD26 positive and negative subsets in SS has never been investigated so far. Thus we have performed qualitative and quantitative PCR based turmor cell determination in the corresponding FACS-separated T-cell fractions. These data were then correlated to clinical outcome and prognosis. Methods: For each of five SS patients with a total of 15 peripheral blood samples the sequences of clonal TCR-gamma and/or TCR-beta rearrangements were established. Then clone-specific qualitative und quantitative (real-time) PCR have been developed for each case. Using these PCR, we estimated presence and frequency of tumor cells in FACS-sorted CD3+CD7+/- as well as CD3+CD26+/- T-cell subsets. Results: The qualitative PCR showed that the malignant T-cells can be both: CD7 positive or negative, the same is true for CD26. The quantitative PCR demonstrated that CD7+ as well as CD7- tumor cells can occur simultaneously whereas CD26- tumor cells predominate by far. The individual tumor cell phenotypes did not fluctuate substantially in the disesase course, but considerable interindividual variations were seen. Furthermore we found in our patients, that CD7+ tumor cells may be a factor for a more favourable prognosis. Conclusions: The tumor cells in SS have mostly a CD3+CD7+CD26- as well as CD3+CD7- CD26- phenotyp. Thus, the tumor burden in this disease can be assessed by an estimation of the CD26- T-cells. The significance of a CD7+ t-cell clone for a better prognosis has to be re-evaluated in a larger patient-collective.