Tracking the source of the hepatitis B virus-specific CD8 T cells during lamivudine treatment

Lamivudine treatment in chronic hepatitis B leads to the reconstitution of virus-specific T cells in the circulation, but it is not clear whether this is the preferential result of T cell efflux from the liver or lymph nodes. To address this question, the frequency and function of liver-, lymph node-, and blood-derived hepatitis B virus (HBV)-specific CD8 T cells were analyzed in patients treated with lamivudine and undergoing liver transplantation. HBV-specific CD8 T cells, identified in portal lymph nodes, were able to expand in vitro after antigen-specific stimulation and displayed a heterogeneous profile of cytokine production. These findings suggest that the peripherally reconstituted HBV-specific CD8 T cells can originate from precursor cells within lymph nodes

Ex vivo PD-L1/PD-1 pathway blockade reverses dysfunction of circulating CEA-specific T cells in pancreatic cancer patients

Purpose: Carcinoembryonic antigen (CEA) is a candidate target for cellular immunotherapy of pancreatic cancer. In this study, we have characterized the antigen-specific function of autologous cytotoxic T lymphocytes (CTL) specific for the HLA-A2-restricted peptide, pCEA691-699, isolated from the peripheral T-cell repertoire of pancreatic cancer patients and sought to determine if ex vivo PD-L1 and TIM-3 blockade could enhance CTL function.Experimental Design: CD8+ T-cell lines were generated from peripheral blood mononuclear cells of 18 HLA-A2+ patients with pancreatic cancer and from 15 healthy controls. In vitro peptide-specific responses were evaluated by flow cytometry after staining for intracellular cytokine production and carboxy fluorescein succinimydyl ester cytotoxicity assays using pancreatic cancer cell lines as targets.Results: Cytokine-secreting functional CEA691-specific CTL lines were successfully generated from 10 of 18 pancreatic cancer patients, with two CTL lines able to recognize and kill both CEA691 peptide-loaded T2 cells and CEA+ HLA-A2+ pancreatic cancer cell lines. In the presence of ex vivo PD-L1 blockade, functional CEA691-specific CD8+ T-cell responses, including IFNγ secretion and proliferation, were enhanced, and this effect was more pronounced on Ag-specific T cells isolated from tumor draining lymph nodes.Conclusions: These data demonstrate that CEA691-specific CTL can be readily expanded from the self-restricted T-cell repertoire of pancreatic cancer patients and that their function can be enhanced by PD-L1 blockade. Clin Cancer Res; 1-12. ©2017 AACR

Identification of a Dual-Specific T Cell Epitope of the Hemagglutinin Antigen of an H5 Avian Influenza Virus in Chickens

Avian influenza viruses (AIV) of the H5N1 subtype have caused morbidity and mortality in humans. Although some migratory birds constitute the natural reservoir for this virus, chickens may play a role in transmission of the virus to humans. Despite the importance of avian species in transmission of AIV H5N1 to humans, very little is known about host immune system interactions with this virus in these species. The objective of the present study was to identify putative T cell epitopes of the hemagglutinin (HA) antigen of an H5 AIV in chickens. Using an overlapping peptide library covering the HA protein, we identified a 15-mer peptide, H5(246-260), within the HA1 domain which induced activation of T cells in chickens immunized against the HA antigen of an H5 virus. Furthermore, H5(246-260) epitope was found to be presented by both major histocompatibility complex (MHC) class I and II molecules, leading to activation of CD4+ and CD8+ T cell subsets, marked by proliferation and expression of interferon (IFN)-gamma by both of these cell subsets as well as the expression of granzyme A by CD8+ T cells. This is the first report of a T cell epitope of AIV recognized by chicken T cells. Furthermore, this study extends the previous finding of the existence of dual-specific epitopes in other species to chickens. Taken together, these results elucidate some of the mechanisms of immune response to AIV in chickens and provide a platform for creation of rational vaccines against AIV in this species

Dissecting the mechanism of intracellular Mycobacterium smegmatis growth inhibition by Platelet activating factor C-16

Mycobacterium tuberculosis (M.tb) infection results in approximately 1.3 million human deaths each year. M.tb resides primarily inside macrophages, and maintains persistent infection. In response to infection and inflammation, platelet activating factor C-16 (PAF C16), a phospholipid compound, is released by various cells including neutophils and monocytes. We have recently shown that PAF C-16 can directly inhibit the growth of two representative non-pathogenic mycobacteria, Mycobacterium bovis BCG and Mycobacterium smegmatis (M. smegmatis), by damaging the bacterial cell membrane. Here, we have examined the effect of PAF C-16 on M. smegmatis residing within macrophages, and identified mechanisms involved in their growth inhibitory function. Our results demonstrated that exogenous PAF C-16 inhibited the growth of M. smegmatis inside phagocytic cells of monocytic cell line, THP1; this effect was partially blocked by PAF receptor antagonists, suggesting the involvement of PAF receptor-mediated signalling pathways. Arachidonic acid, a downstream metabolite of PAF C-16 signalling pathway, directly inhibited the growth of M. smegmatis in vitro. Moreover, the inhibition of phospholipase C and phospholipase A2 activities, involved in PAF C-16 signalling pathway, increased survival of intracellular M. smegmatis. Interestingly, we also observed that inhibition of inducible nitric oxide synthase (iNOS) enzyme and antibody-mediated neutralization of TNF-α partially mitigated the intracellular growth inhibitory effect of PAF C-16. Use of a number of PAF C-16 structural analogues, including Lyso-PAF, 2-O-methyl PAF, PAF C-18 and Hexanolamino PAF, revealed that the presence of acetyl group (CH3CO) at sn-2 position of the glycerol backbone of PAF is important for the intracellular growth inhibition activity against M. smegmatis. Taken together, these results suggest that exogenous PAF C-16 treatment inhibits intracellular M. smegmatis growth, at least partially, in a nitric oxide and TNF-α dependent manner

Marek’s Disease Virus Modulates T Cell Proliferation via Activation of Cyclooxygenase 2-Dependent Prostaglandin E2

Copyright © 2021 Kamble, Gurung, Kaufer, Pathan and Behboudi. Marek’s disease virus (MDV), an avian alphaherpesvirus, infects chickens, transforms CD4+ T cells, and induces immunosuppression early during infection. However, the exact mechanisms involved in MDV-induced immunosuppression are yet to be identified. Here, our results demonstrate that MDV infection in vitro and in vivo induces activation of cyclooxygenase-2 (COX-2) and production of prostaglandin E2 (PGE2). This exerts its inhibitory effects on T cell proliferation at day 21 post infection via PGE2 receptor 2 (EP2) and receptor 4 (EP4). Impairment of the MDV-induced T cell proliferation was associated with downregulation of IL-2 and transferrin uptake in a COX-2/PGE2 dependent manner in vitro. Interestingly, oral administration of a COX-2 inhibitor, meloxicam, during MDV infection inhibited COX-2 activation and rescued T cell proliferation at day 21 post infection. Taken together, our results reveal a novel mechanism that contributes to immunosuppression in the MDV-infected chickens.U.K. Research and Innovation Biotechnology and Biological Sciences Research Council Grants BBS/E/I/00001825, BBS/E/I/00007030, BBS/E/I/00007031, BB/S01506X/1, BBS/E/I/00002529, BBS/E/I/00007039, BBS/E/I/00007032, BB/N002598/1 and BB/V019031/1

Expansion of Anti-Mesothelin Specific CD4(+) and CD8(+) T Cell Responses in Patients with Pancreatic Carcinoma.

We aimed to assess the status of naturally occurring CD4(+) and CD8(+) T cell responses to a tumour associated antigen, Mesothelin, in patients with pancreatic carcinoma and study the effects of elevated IL-10 on Mesothelin-specific T cell responses. For that sake, short term T cell lines were generated from PBMCs of 16 healthy controls, 15 patients with benign pancreatic diseases and 25 patients with pancreatic carcinoma and Mesothelin-specific CD4(+) and CD8(+) T cell responses were analysed using intracellular cytokine assays for IFN-γ. Plasma levels of IL-10 and Mesothelin were measured using cytometric bead array and ELISA assay, respectively. The blocking assays were performed to assess the effects of IL-10 on Mesothelin-specific T cell responses. Here, we demonstrate that the plasma levels of Mesothelin and IL-10 are significantly increased in patients with pancreatic carcinoma. Additionally, we found that (a) Mesothelin-specific T cell responses are significantly expanded in cancer patients (p = 0.0053), (b) the multifunctional CD4(+) T cell response is directed toward a broad repertoire of epitopes within the Mesothelin protein. (c) Mesothelin-specific CD4+ T cell response is directly inhibited by elevated IL-10 in cancer patients. These data provides evidence for the use of Mesothelin as an immunogen for tumour-specific T cell response

Expansion of anti-AFP Th1 and Tc1 responses in hepatocellular carcinoma occur in different stages of disease

Copyright @ 2010 Cancer Research UK. This work is licensed under the Creative Commons Attribution-NonCommercial-Share Alike 3.0 Unported License. To view a copy of this license, visit http://creativecommons.org/licenses/by-nc-sa/3.0/.Background: α-Fetoprotein (AFP) is a tumour-associated antigen in hepatocellular carcinoma (HCC) and is a target for immunotherapy. However, there is little information on the pattern of CD4 (Th1) and CD8 (Tc1) T-cell response to AFP in patients with HCC and their association with the clinical characteristics of patients. Methods: We therefore analysed CD4 and CD8 T-cell responses to a panel of AFP-derived peptides in a total of 31 HCC patients and 14 controls, using an intracellular cytokine assay for IFN-γ. Results: Anti-AFP Tc1 responses were detected in 28.5% of controls, as well as in 25% of HCC patients with Okuda I (early tumour stage) and in 31.6% of HCC patients with stage II or III (late tumour stages). An anti-AFP Th1 response was detected only in HCC patients (58.3% with Okuda stage I tumours and 15.8% with Okuda stage II or III tumours). Anti-AFP Th1 response was mainly detected in HCC patients who had normal or mildly elevated serum AFP concentrations (P=0.00188), whereas there was no significant difference between serum AFP concentrations in these patients and the presence of an anti-AFP Tc1 response. A Th1 response was detected in 44% of HCC patients with a Child–Pugh A score (early stage of cirrhosis), whereas this was detected in only 15% with a B or C score (late-stage cirrhosis). In contrast, a Tc1 response was detected in 17% of HCC patients with a Child–Pugh A score and in 46% with a B or C score. Conclusion: These results suggest that anti-AFP Th1 responses are more likely to be present in patients who are in an early stage of disease (for both tumour stage and liver cirrhosis), whereas anti-AFP Tc1 responses are more likely to be present in patients with late-stage liver cirrhosis. Therefore, these data provide valuable information for the design of vaccination strategies against HCC.Association for International Cancer Research and Polkemmet Fund, London Clinic

No germline mutations in supposed tumour suppressor genes SAFB1 and SAFB2 in familial breast cancer with linkage to 19p

<p>Abstract</p> <p>Background</p> <p>The scaffold attachment factor B1 and B2 genes, <it>SAFB1/SAFB2 </it>(both located on chromosome 19p13.3) have recently been suggested as tumour suppressor genes involved in breast cancer development. The assumption was based on functional properties of the two genes and loss of heterozygosity of intragenic markers in breast tumours further strengthened the postulated hypothesis. In addition, linkage studies in Swedish breast cancer families also indicate the presence of a susceptibility gene for breast cancer at the 19p locus. Somatic mutations in <it>SAFB1/SAFB2 </it>have been detected in breast tumours, but to our knowledge no studies on germline mutations have been reported. In this study we investigated the possible involvement of <it>SAFB1/SAFB2 </it>on familiar breast cancer by inherited mutations in either of the two genes.</p> <p>Results</p> <p>Mutation analysis in families showing linkage to the <it>SAFB1/2 </it>locus was performed by DNA sequencing. The complete coding sequence of the two genes <it>SAFB1 </it>and <it>SAFB2 </it>was analyzed in germline DNA from 31 affected women. No missense or frameshift mutations were detected. One polymorphism was found in <it>SAFB1 </it>and eight polymorphisms were detected in <it>SAFB2</it>. MLPA-anlysis showed that both alleles of the two genes were preserved which excludes gene inactivation by large deletions.</p> <p>Conclusion</p> <p><it>SAFB1 </it>and <it>SAFB2 </it>are not likely to be causative of the hereditary breast cancer syndrome in west Swedish breast cancer families.</p

Gold Nanoparticle Delivery of Modified CpG Stimulates Macrophages and Inhibits Tumor Growth for Enhanced Immunotherapy

Gold nanoparticle accumulation in immune cells has commonly been viewed as a side effect for cancer therapeutic delivery; however, this phenomenon can be utilized for developing gold nanoparticle mediated immunotherapy. Here, we conjugated a modified CpG oligodeoxynucleotide immune stimulant to gold nanoparticles using a simple and scalable selfassembled monolayer scheme that enhanced the functionality of CpG in vitro and in vivo. Nanoparticles can attenuate systemic side effects by enhancing CpG delivery passively to innate effector cells. The use of a triethylene glycol (TEG) spacer on top of the traditional poly-thymidine spacer increased CpG macrophage stimulatory effects without sacrificing DNA content on the nanoparticle, which directly correlates to particle uptake. In addition, the immune effects of modified CpGAuNPs were altered by the core particle size, with smaller 15 nm AuNPs generating maximum immune response. These TEG modified CpG-AuNP complexes induced macrophage and dendritic cell tumor infiltration, significantly inhibited tumor growth, and promoted survival in mice when compared to treatments with free CpG