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Cross-reactivity between type II collagen (CII) and C1q, the collagen-like subunit of the first component of complement, has been demonstrated in synovial fluid (SF) from rheumatoid arthritis (RA) patients. Many authors have studied autoimmunity to CII in R.A, but little work has been done on autoimmunity to C1q in RA. In the data presented here, we have been able to show that in addition to native C1q, an altered form of C1q is present in SF from RA patients. Furthermore, a low molecular weight form of C1q is present in R.A SF, although its role, if any, in the pathogenesis of RA is unclear. The presence in these RA SF of C1q-specific antibodies (IgG and IgM) has been studied and we have partially characterized the antibody moieties involved. As well as binding to C1q and fragments representing the collagen-tails from C1q, 7 S IgG autoantibodies against C1q also bind to a C1q molecule altered in vitro by incubation with reactive oxygen species and to the non-apeptide KGEQGEPGA (representing residues 26–34 from the C1q A-chain), which has previously been shown to suppress the onset of CII-induced arthritis in an animal model. [ABSTRACT FROM AUTHOR]

Background Research suggests a positive association between coeliac disease and tuberculosis (TB), but that research has often been limited to in-patients and small sample size. We examined the relationship between TB and coeliac disease. Aim To examine the association of TB and coeliac disease. Methods We collected biopsy data from all pathology departments in Sweden (n = 28) to identify individuals who were diagnosed with coeliac disease between 1969 and 2007 (Marsh 3: villous atrophy; n = 29 026 unique individuals). Population-based sex- and age-matched controls were selected from the Total Population Register. Using Cox regression, we calculated hazard ratios (HRs) for TB from data in the Swedish national health registers. Results Individuals with coeliac disease were at increased risk of TB (HR = 2.0; 95% CI = 1.3-3.0) (during follow-up, 31 individuals with coeliac disease and 74 reference individuals had a diagnosis of TB). The absolute risk of TB in patients with coeliac disease was 10 / 100 000 person-years with an excess risk of 5 / 100 000. Risk estimates were the highest in the first year. Restricting our outcome to a diagnosis of TB confirmed by (I) a record of TB medication (HR = 2.9; 95% CI = 1.0-8.3), (II) data in the National Surveillance System for Infectious Diseases in Sweden (HR = 2.6; 95% CI = 1.3-5.2) or (III) positive TB cultivation (HR = 3.3; 95% CI = 1.6-6.8) increased risk estimates. The positive association between coeliac disease and TB was also observed before the coeliac disease diagnosis (odds ratio = 1.6; 95% CI = 1.2-2.1). Conclusion We found a moderately increased risk of tuberculosis in patients with coeliac disease. [ABSTRACT FROM AUTHOR]

In this study we have analyzed CD30-antigen expression in three melanoma-directed cytotoxic T lymphocyte (CTL) clones with a T helper 0 (Th0)-like cytokine secretion profile (i.e. interleukin (IL)-4, IL-5, and interferon (IFN)-γ). We show that all CTL clones expressed high levels of CD30 upon contact with the autologous tumour cells. One CTL clone, termed A2 with a monoclonal feature was selected for further analyses and found its CD30 expression dependent on the presence of IL-4. Functionally, a CD30-expressing A2 CTL was capable of producing higher amounts of IFN-γ (up to 1.5-fold) and IL-4 (up to two-fold) than its CD30- counterpart. Furthermore, CD30-positive A2 CTL displayed an at least three-fold greater proliferative response to the tumour cell stimulation, contrasting with CD30- CTL. However, the antitumour cytotoxic activity of A2 CTL was not modulated by the CD30 expression. These results suggest that CD30 antigen can be inducible on a subset of tumour-directed CD8+ CTL, and that this subset of cells may have profound effector functions, such as cytokine secretion, proliferation, and cytotoxicity. [ABSTRACT FROM AUTHOR]

To investigate patterns of care and prognostic benefits of MRI, FDG-PET/CT and image-guidance in re-irradiation of locoregionally recurrent or second primary head-and-neck squamous cell carcinomas (r/s HNSCCs) within a multicenter cohort study. Patients receiving re-irradiation for r/s HNSCC between 2009 and 2020 at 16 tertiary cancer centers in Germany were retrospectively analyzed in terms of MRI and FDG-PET/CT usage for treatment planning and regarding image-guidance frequency during re-irradiation. Patterns of use of these modalities over time were analyzed by binary logistic regression analysis, and the association between the usage of these modalities and best locoregional treatment response was analyzed with chi-square tests. Cumulative incidence analyses of locoregional failures with death as competing event were performed. In the total cohort of 297 patients, 226 (76%) were male, median age was 62 years (IQR, 56-70), and median ECOG was 1 (IQR, 1-2). There were 260 locoregionally recurrent HNSCCs, and 37 second primary HNSCCs; 44 patients (15%) had distant metastases at the time of re-irradiation. MRI and FDG-PET/CT was used for re-irradiation planning in 117 (39%) and 71 patients (24%), respectively. In median, image guidance (IGRT) was performed twice weekly (IQR, 1-5), usually with cone beam CTs or megavolt-CTs, and 85 patients (29%) received daily IGRT during re-irradiation. Usage of MRI (OR = 0.967; 95% CI, 0.892-1.048; p =.416), FDG-PET/CT (OR = 1.053; 95% CI, 0.960-1.156; p =.274), or daily IGRT (OR = 1.057; 95% CI, 0.968-1.115; p =.218) did not increase in frequency over time within the analyzed time span but was significantly dependent on the treatment center (χ2(15), P <.001 for all modalities). Daily IGRT was associated with a higher rate of at least stable disease after re-irradiation as assessed by RECIST criteria (χ2(1) = 4.011, p <.05). There was a trend towards better RECIST-assessed treatment response for MRI (χ2(1) = 3.223, p =.073) and FDG-PET/CT (χ2(1) = 2.792, p =.095) as part of the re-irradiation planning process. Incidence of locoregional failures was not dependent on MRI (SHR = 0.94; 95% CI, 0.67-1.33; p = 0.741, Fine-Gray), FDG-PET/CT (SHR = 0.88; 95% CI, 0.59-1.33; p = 0.552) or daily IGRT (SHR = 0.76; 95% CI, 0.51-1.14, p = 0.182), There was a trend towards lower acute grade 3/4-toxicities in patients receiving daily IGRT (χ2(1) = 3.354, p = 0.067). Our data suggest that daily IGRT may increase disease control and should be regularly applied for re-irradiation of r/s HNSCCs. MRI and FDG-PET/CT usage were not associated with the incidence of locoregional failures after re-irradiation. However, prospective trials with multiparametric MRI and/or FDG-PET/CT for optimal re-irradiation planning are warranted. [ABSTRACT FROM AUTHOR]

A response from J.F. Ludvigsson and colleagues to a letter to the editor about their article related to tuberculosis (TB) in coeliac disease in the May 2011 issue is presented.

In response to the 2009-2010 influenza A(H1N1)pdm09 pandemic, a mass vaccination programme with the AS03-adjuvanted influenza A(H1N1) vaccine Pandemrix was initiated in Sweden. Unexpectedly, there were a number of narcolepsy cases amongst vaccinated children and adolescents reported. In this review, we summarize the results of a joint cross-disciplinary national research effort to investigate the adverse reaction signal from the spontaneous reporting system and to better understand possible causative mechanisms. A three- to fourfold increased risk of narcolepsy in vaccinated children and adolescents was verified by epidemiological studies. Of importance, no risk increase was observed for the other neurological and autoimmune diseases studied. Genetic studies confirmed the association with the allele HLA- DQB1*06:02, which is known to be related to sporadic narcolepsy. Furthermore, a number of studies using cellular and molecular experimental models investigated possible links between influenza vaccination and narcolepsy. Serum analysis, using a peptide microarray platform, showed that individuals who received Pandemrix exhibited a different epitope reactivity pattern to neuraminidase and haemagglutinin, as compared to individuals who were infected with H1N1. Patients with narcolepsy were also found to have increased levels of interferon-gamma production in response to streptococcus-associated antigens. The chain of patient-related events and the study results emerging over time were subjected to intense nationwide media attention. The importance of transparent communication and collaboration with patient representatives to maintain public trust in vaccination programmes is also discussed in the review. Organizational challenges due to this unexpected event delayed the initiation of some of the research projects, still the main objectives of this joint, cross-disciplinary research effort were reached, and important insights were acquired for future, similar situations in which a fast and effective task force may be required to evaluate vaccination-related adverse events. [ABSTRACT FROM AUTHOR]

Background Type 1 narcolepsy is a neurological disorder characterized by excessive daytime sleepiness and cataplexy associated with the HLA allele DQB1*06:02. Genetic predisposition along with external triggering factors may drive autoimmune responses, ultimately leading to the selective loss of hypocretin-positive neurons. Objective The aim of this study was to investigate potential aetiological factors in Swedish cases of postvaccination (Pandemrix) narcolepsy defined by interferon-gamma ( IFNγ) production from immune cells in response to molecularly defined targets. Methods Cellular reactivity defined by IFNγ production was examined in blood from 38 ( HLA- DQB1*06:02+) Pandemrix-vaccinated narcolepsy cases and 76 (23 HLA- DQB1*06:02+ and 53 HLA- DQB1*06:02−) control subjects, matched for age, sex and exposure, using a variety of different antigens: β-haemolytic group A streptococcal ( GAS) antigens (M5, M6 and streptodornase B), influenza (the pandemic A/H1N1/California/7/09 NYMC X-179A and A/H1N1/California/7/09 NYMC X-181 vaccine antigens, previous Flu-A and -B vaccine targets, A/H1N1/Brisbane/59/2007, A/H1N1/Solomon Islands/3/2006, A/H3N2/Uruguay/716/2007, A/H3N2/Wisconsin/67/2005, A/H5N1/Vietnam/1203/2004 and B/Malaysia/2506/2004), noninfluenza viral targets ( CMVpp65, EBNA-1 and EBNA-3) and auto-antigens (hypocretin peptide, Tribbles homolog 2 peptide cocktail and extract from rat hypothalamus tissue). Results IFN-γ production was significantly increased in whole blood from narcolepsy cases in response to streptococcus serotype M6 ( P = 0.0065) and streptodornase B protein ( P = 0.0050). T-cell recognition of M6 and streptodornase B was confirmed at the single-cell level by intracellular cytokine ( IL-2, IFNγ, tumour necrosis factor-alpha and IL-17) production after stimulation with synthetic M6 or streptodornase B peptides. Significantly, higher ( P = 0.02) titres of serum antistreptolysin O were observed in narcolepsy cases, compared to vaccinated controls. Conclusion β-haemolytic GAS may be involved in triggering autoimmune responses in patients who developed narcolepsy symptoms after vaccination with Pandemrix in Sweden, characterized by a Streptococcus pyogenes M-type-specific IFN-γ cellular immune response. [ABSTRACT FROM AUTHOR]

Pretransplant influenza vaccination of the donor or allogeneic hematopoietic SCT (HSCT) candidate was evaluated in a randomized study. One hundred and twenty-two HSCT recipients and their donors were assigned to three randomization groups: no pretransplant vaccination (n=38), donor pretransplant vaccination (n=44) or recipient pretransplant vaccination (n=40). Specific IgG was assessed by both hemagglutinin inhibition (HI) and, in 57 patients, by an indirect influenza-specific ELISA at specified times after HSCT. Vaccinated donors had seroprotective HI titers for Ags H1 and H3 (P<0.001) compared with the other groups at the time of donation. The titers against H1 (P=0.028) and H3 (P<0.001) were highest in the pretransplant recipient vaccination group until day 180 after transplantation. A significant difference was found in the specific Ig levels against pandemic H1N1 at 6 months after SCT (P=0.02). The mean IgG levels against pandemic H1N1 and generic H1N1 and H3N2 were highest in the pretransplant recipient vaccination group. We conclude that pretransplant recipient vaccination improved the influenza-specific seroprotection rates. [ABSTRACT FROM AUTHOR]

Background Influenza vaccination is generally recommended to hematopoietic stem cell transplant ( HSCT) recipients. However, the seasonal subunit vaccination response is frequently suboptimal, and alternate more efficient vaccination systems must be examined. We compared the immunogenicity of an adjuvanted virosomal influenza and subunit vaccine in HSCT recipients. Methods The immunogenicity after a single dose (0.5 mL) of adjuvanted trivalent virosomal vaccination was evaluated in a study cohort of 21 HSCT recipients and compared to a control cohort of 30 HSCT recipients who received a single dose (0.5 mL) of non-adjuvanted seasonal trivalent subunit vaccination over 4 seasons from 2010 to 2014. Whole blood interferon-gamma ( IFN-γ) release assays were tested, both before and 30 days after vaccination, in response to influenza pandemic (pdm) H1N1, H3N2, and B antigens. HLA-A*02 dextramers, to gauge for the absolute number of antigen-specific CD8+ T-cells, and pdm 2009 hemagglutinin inhibition ( HI) assays, to test for neutralizing antibodies, were used as immunological readouts. Results The pdm HI titers were poor in both cohorts with only 23% (5/21) after virosomal vaccination and 13.3% (4/30) in the seasonal vaccine cohort having protective titers (≥40). The delta change of IFN-γ production in response to influenza pdm H1N1 ( P = 0.005) and influenza B antigens ( P = 0.01) were significantly elevated in blood from individuals who received the virosomal as compared to the seasonal vaccine. The IFN-γ response to pdm H1N1 was stronger ( P < 0.001), as compared to seasonal vaccination, in patients vaccinated >6 month post HSCT. We detected a significant increase in the frequency of matrix 1 ( GILGFVTL) dextramer-specific CD8+ T-cells after the virosomal vaccine ( P = 0.01). No differences were seen in the hemagglutinin-specific CD8+ T-cells between the 2 cohorts. Conclusion Vaccination using a virosomal delivery system is beneficial in eliciting robust cellular immune responses to pdm H1N1 influenza in SCT recipients. [ABSTRACT FROM AUTHOR]

Tuberculosis ( TB) is an airborne infectious disease that kills almost two million individuals every year. Multidrug-resistant ( MDR) TB is caused by strains of Mycobacterium tuberculosis ( M. tb) resistant to isoniazid and rifampin, the backbone of first-line antitubercular treatment. MDR TB affects an estimated 500 000 new patients annually. Genetic analysis of drug-resistant MDR- TB showed that airborne transmission of undetected and untreated strains played a major role in disease outbreaks. The need for new TB vaccines and faster diagnostics, as well as the development of new drugs, has recently been highlighted. The major problem in terms of current TB research and clinical demands is the increasing number of cases of extensively drug-resistant and 'treatment-refractory' TB. An emerging scenario of adjunct host-directed therapies is intended to target pulmonary TB where inflammatory processes can be deleterious and lead to immune exhaustion. 'Target-organ-saving' strategies may be warranted to prevent damage to infected tissues and achieve focused, clinically relevant and long-lasting anti- M. tb cellular immune responses. Candidates for such interventions may be biological agents or already approved drugs that can be 're-purposed' to interfere with biologically relevant cellular checkpoints. Here, we review current concepts of inflammation in TB disease and discuss candidate pathways for host-directed therapies to achieve better clinical outcomes. [ABSTRACT FROM AUTHOR]

The first cases of totally drug-resistant ( TDR) tuberculosis ( TB) were reported in Italy 10 years ago; more recently, cases have also been reported in Iran, India and South Africa. Although there is no consensus on terminology, it is most commonly described as 'resistance to all first- and second-line drugs used to treat TB'. Mycobacterium tuberculosis ( M.tb) acquires drug resistance mutations in a sequential fashion under suboptimal drug pressure due to monotherapy, inadequate dosing, treatment interruptions and drug interactions. The treatment of TDR- TB includes antibiotics with disputed or minimal effectiveness against M.tb, and the fatality rate is high. Comorbidities such as diabetes and infection with human immunodeficiency virus further impact on TB treatment options and survival rates. Several new drug candidates with novel modes of action are under late-stage clinical evaluation (e.g. delamanid, bedaquiline, SQ109 and sutezolid). 'Repurposed' antibiotics have also recently been included in the treatment of extensively drug resistant TB. However, because of mutations in M.tb, drugs will not provide a cure for TB in the long term. Adjunct TB therapies, including therapeutic vaccines, vitamin supplementation and/or repurposing of drugs targeting biologically and clinically relevant molecular pathways, may achieve better clinical outcomes in combination with standard chemotherapy. Here, we review broader perspectives of drug resistance in TB and potential adjunct treatment options. [ABSTRACT FROM AUTHOR]

Interleukin-7 (IL-7) and the IL-7 receptor (IL-7R) have been shown to be alternatively spliced in infectious diseases. We tested IL-7 and IL-7R splicing in a tuberculosis (TB)-vaccine/Mycobacterium tuberculosis (Mtb)-challenge model in non-human primates (NHPs). Differential IL-7 splicing was detected in peripheral blood mononuclear cells (PBMCs) from 15/15 NHPs showing 6 different IL-7 spliced isoforms. This pattern did not change after infection with virulent Mtb. We demonstrated increased IL-7 (6 exon) and IL-17 protein production in lung tissue along with concomitant decreased transforming growth factor-β (TGF-β) from NHPs (vaccinated with a recombinant BCG (rBCG)) who showed increased survival after Mtb challenge. IL-7 increased IL-17 and interferon-γ (IFN-γ) gene and protein expression in PBMCs. Mtb-infected NHPs showed differential IL-7R splicing associated with the anatomical location and tissue origin, that is, in lung tissue, hilus, axillary lymph nodes (LNs) and spleen. Differential splicing of the IL-7R was typical for healthy (non-Mtb infected) and for Mtb-infected lung tissue with a dominant expression of soluble IL-7R (sIL-7R) receptor lacking exon 6 (9:1 ratio of sIL-7R/cell-bound IL-7R). Differential ratios of cell-bound vs sIL-7R could be observed in hilus and axillary LNs from Mtb-infected NHPs with an inversed ratio of 1:9 (sIL-7R/cell-bound IL-7R) in spleen and PBMCs. Soluble IL-7R is exclusively present in lung tissue. [ABSTRACT FROM AUTHOR]

Abstract: IL-7 and IL-7Rα (IL-7R) form a non-redundant ligand receptor system which plays a crucial role in human T cell immunity. Both IL-7 and IL-7R are multi-exonal genes and exhibit alternative splicing. We measured the relative distribution of IL-7 and IL-7R spliced mRNA from patients with MS and healthy individuals and observed extensive alternative splicing of both genes with marked differences in proportional transcript expression levels. We report here for the first time that the IL-7 transcript, lacking exon 4, and not the full length IL-7 represents the dominant IL-7 RNA transcript in human PBMCs and a novel IL-7R splice variant lacking exons 5, 6 and 7. [Copyright &y& Elsevier]

Alternative splicing of pre-mRNA increases proteomic diversity, a crucial mechanism in defining tissue identity. We demonstrate differentially spliced interleukin (IL)-7 in distinct anatomic areas in the adult, in developing human brains and in normal human neuronal progenitor (NHNP) cells. IL-7c (c, the canonical form spanning all six exons) or its variants IL-7δ5, δ4 or δ4/5 were cloned and expressed as recombinant proteins. IL-7 and splice variants were able to shift the differentiation of NHNP cells as compared with the diluent control (P<0.01) defined by anti-β (III)-tubulin and glial fibrillary acidic protein expression, with different degrees (IL-7c>δ4/5>IL-7δ5); IL-7δ4 exhibited a significantly weaker potency. Differentiation was confirmed by transcriptome analysis of IL-7c-stimulated neural NHNP cells, resulting in 58 differentially expressed genes; some of these are involved in neural differentiation, for example, the developmentally regulated transcription factor krüppel-like factor 12, musashi 2, a translational regulator of cell fate or the sonic hedgehog receptor patch 1. This suggests that IL-7 influences neural development at a molecular level by participating in human brain architecture through glia cell formation: a paradigm that alternative splicing in cytokines, for example, for IL-7, has a physiological role in human organ development and progenitor cell differentiation. [ABSTRACT FROM AUTHOR]

Alternative splicing results in multiple protein isoforms derived from a single gene. The magnitude of this process ranges from a complete loss of function to gain of new function. We examined, as a paradigm, alternative splicing of the non-redundant human cytokine, interleukin-7 (IL-7). We show that extensive IL-7 splicing in human tissues of different histology, including MTB+ granuloma lesions, transformed tissue and tumor cell lines. IL-7 splice variants were expressed as recombinant proteins. A differentially spliced IL-7 isoform, lacking exon 5, leads to STAT-5 phosphorylation in CD4+ and CD8+ T cells, promotes thymocyte maturation and T-cell survival. Human tumor lesions show aberrant IL-7 isoform expression, as compared with the autologous, non-transformed tissue. Alternatively spliced cytokines, such as IL-7, represent candidates for diagnostics and therapeutic interventions.Genes and Immunity (2009) 10, 132–140; doi:10.1038/gene.2008.90; published online 18 December 2008 [ABSTRACT FROM AUTHOR]

The aim of this study targeted the evaluation of the in vivo effect of moxifloxacin in the treatment of patients with severe odontogenic abscesses. This was a prospective, two-armed, randomised, unblinded, monocentric pilot study, which enrolled 21 hospitalized patients with severe odontogenic abscesses. After extraoral incision, patients were either treated with moxifloxacin 400 mg i.v. once daily or amoxicillin/clavulanic acid 2.2 g i.v. three times daily. Primary clinical endpoint was the time until clinical remission, represented by simultaneous assertion of the following criteria: body temperature <38.5°C, no pain at palpation, and mouth opening similar or better than preoperatively. White blood cell count, C-reactive protein, pain, health related quality of life (HR-QoL) and length of hospital stay were recorded as secondary outcome criteria. The mean duration until reaching the primary end point was 6.6 (range, 4.3–8.8) days in the moxifloxacin group and 6.0 (range, 3.8–8.2) days in the amoxicillin/clavulanic acid group. Median days of in-house treatment ranged between five and six days for both groups. HR-QoL was highly impaired in both groups preoperatively and reached near normal on days three and four in both samples. In this pilot investigation, moxifloxacin showed promising results as compared to amoxicillin/clavulanic acid. Therefore, a larger prospective clinical trial using moxifloxacin in severe odontogenic abscesses appears encouraging. We suggest a combination of body temperature, palpatory pain, and subjective pain as a parameter for successful intervention; however, both findings need prospective validation by means of a phase III evaluation. [ABSTRACT FROM AUTHOR]

Challenged by scattered understanding of protective immunity to Mycobacterium tuberculosis (MTB), we have mapped peptide epitopes to human leukocyte antigen (HLA)-A*0101, A*0201, A*1101, A*2402, B*0702, B*0801 and B*1501 of the secreted mycobacterial antigen Ag85B, a vaccine candidate that may be associated with immune protection. Affinity (ED50) and half-life (t1/2, off-rate) analysis for individual peptide species on HLA-A and HLA-B molecules revealed binding ranges between 10−3 and 10−7 M. After selection of the best matches, major histocompatibility complex class I/peptide tetramer complexes were constructed to measure the CD8+ T-cell responses directly ex vivo in peripheral blood mononuclear cells (PBMC) derived from 57 patients with acute pulmonary tuberculosis. Three patterns of (allele-) specific CD8+ recognition were identified: (a). Focus on one dominant epitope with additional recognition of several subdominant T-cell epitopes (HLA-A*0301, A*2402, B*0801 and B*1501); (b). Co-dominant recognition of two distinct groups of peptides presented by HLA-B*0702; and (c). Diverse and broad recognition of peptides presented by HLA-A*0201. Peptides that bound with slow off-rates to class I alleles, that is HLA-A*0201, were associated with low frequency of CD8+ T cells in PBMCs from patients with tuberculosis. HLA-B alleles showed fast off-rates in peptide binding and restricted high numbers (up to 6%) of antigen-specific CD8+ T cells in patients with pulmonary tuberculosis.Genes and Immunity (2007) 8, 334–343; doi:10.1038/sj.gene.6364392; published online 12 April 2007 [ABSTRACT FROM AUTHOR]

Novel diagnostic tools are needed to diagnose latent infection and to provide biologically meaningful surrogate markers to define cellular immune responses against Mycobacterium tuberculosis (MTB). Interferon gamma-based assays have recently been developed in addition to the more than 100-year-old tuberculin skin test (TST) for the immune diagnosis of MTB in blood. The advent of soluble MHC/peptide tetramer molecules allows to objectively enumerate antigen-specific T cells. We identified novel MHC class II-restricted MTB epitopes and used HLA-DR4 tetrameric complexes to visualize ex vivo CD4+ T cells directed against the antigens Ag85B and the 19-kDa lipoprotein, shared between MTB and other Mycobacterium species, and CD4+ T cells which recognize the MTB-associated ESAT-6 antigen. MTB-reactive CD4+ T cells reside predominantly in the CD45RA+ CD28+ and CD45− CD28+ T-cell subset and recognize naturally processed and presented MTB epitopes. HLA-DR4-restricted, Ag85B or ESAT-6-specific CD4+ T cells show similar dynamics over time in peripheral blood mononuclear cells (PBMC) when compared with CD8+ T cells directed against the corresponding HLA-A2-presented MTB epitopes in patients with pulmonary MTB infection and subsequent successful therapy. This was not found to be true for T-cell responses directed against the 19-kDa lipoprotein. The dissection of the cellular immune response in M. tuberculosis infection will enable novel strategies for monitoring MTB vaccine candidates and to gauge CD4+ T cells directed against MTB. [ABSTRACT FROM AUTHOR]

SUMMARY In response to antigenic stimulation, naive MHC-class I restricted and antigen-specific CD8+ CD45RA+ CD28+ T cells undergo clonal expansion, differentiate into CD8+ CD45RO+ memory T cells and convert to CD8+ CD45RA+ CD28- T cells displaying potent immune effector functions upon re-encounter with the nominal antigen. We show that the effector CD8+ CD45RA+ CD28- T cell subset is expanded in peripheral blood lymphocytes (PBL) from patients with human papilloma virus (HPV)+ cervical lesions as well as in PBL from patients with pulmonary tuberculosis. Flow-cytometric cell sorted CD8+ CD45RA+ CD28- and CD8+ CD45RA+ CD28- T cells were tested for recognition of HLA-A2 restricted peptides derived either from the human papillomavirus (HPV)16-E7 gene product, or from M. tuberculosis antigens. Mostly CD8+ CD45+ CD28- T cells define antigen/peptide-specific and MHC-restricted responses. These data were confirmed in PBL from patients with tuberculosis using HLA-A2 tetramer-complexes loaded with a peptide from the M. tuberculosis Ag85b antigen by flow cytometry. The sorting of this T cell subset enables to determine the fine specificity of CD8+ effector T cells without the need for in vitro manipulation. [ABSTRACT FROM AUTHOR]

Recent studies have suggested that vaccination induces alterations in the T cell receptor (TCR) repertoire. We investigate the diversity of the TCR repertoire after immunization with a recombinant hepatitis B surface vaccine in seven healthy subjects in CD8[sup +] T cells in peripheral blood lymphocytes. Cellular immune responses were monitored over time by sorting CD8 T cells followed by TCR-VA and -VB complementarity determining region 3 (CDR3) analysis. Frequency of individual VB families was determined by flow cytometry. TCR-VA/VB repertoires obtained from CD8[sup +] T cells drawn after vaccination were compared to the TCR repertoire determined prior to vaccination. Monoclonal TCR transcripts could be detected exclusively in CD8[sup +], but not in CD4[sup +] T cells. Such monoclonal TCR transcripts were either stable in some individuals, or could only be detected at certain time points after vaccination. Sorting of monoclonal TCR-VB3[sup +] T cells, which constituted up to 5% of the CD8[sup +] T cell population from one individual, revealed that this T cell clone recognizes an epitope provided by the recombinant hepatitis B vaccine presented by MHC-class I on autologous antigen-presenting cells. Examination of the structural anatomy, defined by the TCR, and the frequency of T cells responding to the immunizing antigen may be helpful to provide surrogate markers to monitor cellular immune responses induced by protein antigens utilized for vaccination. [ABSTRACT FROM AUTHOR]

Qualitative differences in the MHC class II antigen processing and presentation pathway may be instrumental in shaping the CD4+ T cell response directed against tumour cells. Efficient loading of many MHC class II alleles with peptides requires the assistance of H2-M, a heterodimeric MHC class II-like molecule. In contrast to the HLA-DM region in humans, the β-chain locus is duplicated in mouse, with the H2-Mb1 (Mb1β-chain distal to H2-Mb2 (Mb2) and the H2-Ma (Ma) α-chain gene). Here, we show that murine MHC class II and H2-M genes are coordinately regulated in murine tumour cell lines by T helper cell 1 (IFN-γ) and T helper cell 2 (IL-4 or IL-10) cytokines in the presence of the MHC class II-specific transactivator CIITA as determined by mRNA expression and Western blot analysis. Furthermore, Mαβ1 and Mαβ2 heterodimers are differentially expressed in murine tumour cell lines of different histology. Both H2-M isoforms promote equally processing and presentation of native protein antigens to H2-A[SUPd]- and H2-E[SUPd]-restricted CD4+ T cells. Murine tumour cell lines could be divided into three groups: constitutive MHC class II and CIITA expression; inducible MHC class II and CIITA expression upon IFN-γ-treatment; and lack of constitutive and IFN-γ-inducible MHC class II and CIITA expression. These differences may impact on CD4+ T cell recognition of cancer cells in murine tumour models. [ABSTRACT FROM AUTHOR]

SP-A is found principally in the lung, and has been associated with lamellar bodies also found in the synovial joint. Both SP-A and C1q contain collagen-like regions, and SP-A and C1q have some structural similarities, both having a globular head region and a collagen-like tail. Here we are able to show that (i) autoreactivity to SP-A, as expressed by IgG and IgM autoantibodies, is present in synovial fluid (SF) isolated from patients with rheumatoid arthritis (RA); (ii) in absorption experiments only a limited degree of cross-reactivity between autoantibodies reactive with C1q and SP-A is observed; (iii) there is no cross-reactivity between autoantibodies reactive with type II collagen (CII) and those reactive with SP-A or C1q; (iv) autoantibodies react with polymeric (dimers and larger) SP-A, but not with monomeric SP-A subunits, indicating that a degree of quaternary structure is required for antibody binding. Unlike CII, which not accessible in the normal joint, both SP-A and C1q are available within the SF in patients with RA and may therefore provide antigens driving an autoimmune response directed against collagen-like structures. [ABSTRACT FROM AUTHOR]