The role of the bound peptide in alloreactive T-cell recognition is controversial, ranging from pep-tide-independent to peptide-specific recognition of alloreactive T-cells. The aim of this study is to find the eviden...The role of the bound peptide in alloreactive T-cell recognition is controversial, ranging from pep-tide-independent to peptide-specific recognition of alloreactive T-cells. The aim of this study is to find the evidence that there exist peptide/MHC complex (pMHC)-specific CTLs among alloreactive T cells generated with long-term mixed lymphocytes culture (LTMLC). A single pMHC was manipulated by loading the TAP-defective, HLA-A2 expressing T2 cells with a viral peptide (LMP2A426-434) or a self-peptide (Tyr369-377). The PBLs samples from 4 HLA-A2 positive (HLA-A2+ve) and 4 HLA-A2 negative (HLA-A2-ve) donors were included in this study. The HLA-A2+ve PBL co-cultured with the LMP2A426-434 pulsed T2 (T2/LMP) stands for the nominal T-cell response to a viral antigen, and the HLA-A2-ve PBLs co-cultured with the Tyr369-377 pulsed T2 (T2/Tyr) for alloreactive T-cell response to an allogeneic antigen. The specificity of the expanded CTLs after the LTMLC was detected by their specific cytotoxicity and binding ability to specific pMHC-tetramer. An HLA-A2 restricted, HIV peptide (Gag77-85)was included for control. The cultural bulk of HLA-A2+ve PBLs with the T2/LMP showed an elevated specific cytotoxicity against the T2/LMP compared to that against the T2/HIV (26.52%±3.72% vs 7.01%±0.87%, P<0.001), and an increased frequency of binding to LMP-tetramer compared to that binding to HIV-tetramer (0.98%±0.33% vs 0.05%±0.01%, P=0.0014). The cultural bulk of HLA-A2-ve PBLs with the T2/Tyr showed a more active cytotoxicity against the T2/Tyr than that against T2/HIV (28.07%±2.58% vs 6.87%±0.01 %, P<0.001), and a higher frequency of binding to the Tyr-tetramer than that binding to the HIV-tetramer (0.88%±0.3% vs 0.06%±0.03%, P=0.0018). Our results indicate that the LTMLC is able to expand the viral antigen-specific CTLs as well as allogeneic antigen-specific CTLs. A relatively large proportion of alloreactive CTLs should be pMHC-specific, i.e., the specificity of the alloreactive lines depends on both the bound peptide and the展开更多
CD4^(+)T cells integrate well-defined signals from the T-cell receptor(TCR)(signal 1)and a host of costimulatory molecules(signal 2)to initiate clonal expansion and differentiation into diverse functional T helper(Th)...CD4^(+)T cells integrate well-defined signals from the T-cell receptor(TCR)(signal 1)and a host of costimulatory molecules(signal 2)to initiate clonal expansion and differentiation into diverse functional T helper(Th)subsets.However,our ability to guide the expansion of context-appropriate Th subsets by deploying these signals in vaccination remains limited.Using cell-based vaccines,we selectively amplified signal 1 by exclusive presentation of an optimized peptide:MHC II(pMHC II)complex in the absence of classic costimulation.Contrary to expectations,amplified signal 1 alone was strongly immunogenic and selectively expanded highaffinity TCR clonotypes,despite delivering intense TCR signals.In contrast to natural infection or standard vaccines,amplified signal 1,presented by a variety of professional and nonprofessional antigen-presenting cells(APCs),induced exclusively polyfunctional Th1 effector and memory cells,which protected against retroviral infection and tumor challenge,and expanded tumor-reactive CD4^(+)T cells otherwise rendered unresponsive in tumor-bearing hosts.Together,our findings uncover a default Th1 response to ample signal 1 and offer a means to selectively prime such protective responses by vaccination.展开更多
Untreated human immunodeficiency virus(HIV)infections usually lead to death from AIDS,although the rate of the disease progression varies widely among individuals.The cytotoxic T lymphocyte(CTL)response,which is restr...Untreated human immunodeficiency virus(HIV)infections usually lead to death from AIDS,although the rate of the disease progression varies widely among individuals.The cytotoxic T lymphocyte(CTL)response,which is restricted by highly polymorphic MHC class I alleles,plays a central role in controlling HIV replication.It is now recognized that the antiviral efficacy of CTLs at the single cell level is dependent on their antigen specificity and is important in determining the quality of host response to viruses so that the individual will remain asymptomatic.However,because of the extreme mutational plasticity of HIV,HIV-specific CTL responses are continuously and dynamically changing.In order to rationally design an effective vaccine,the questions as to what constitutes an effective antiviral CTL response and what characterizes a potent antigenic peptide to induce such responses are becoming highlighted as needing to be answered.展开更多
基金the National Natural Science Foundation of China (Grant Nos.30271201 and 30490241), and the "973" Project of the Ministry of Science and Technology of China (Grant No. 2001CB510008)
文摘The role of the bound peptide in alloreactive T-cell recognition is controversial, ranging from pep-tide-independent to peptide-specific recognition of alloreactive T-cells. The aim of this study is to find the evidence that there exist peptide/MHC complex (pMHC)-specific CTLs among alloreactive T cells generated with long-term mixed lymphocytes culture (LTMLC). A single pMHC was manipulated by loading the TAP-defective, HLA-A2 expressing T2 cells with a viral peptide (LMP2A426-434) or a self-peptide (Tyr369-377). The PBLs samples from 4 HLA-A2 positive (HLA-A2+ve) and 4 HLA-A2 negative (HLA-A2-ve) donors were included in this study. The HLA-A2+ve PBL co-cultured with the LMP2A426-434 pulsed T2 (T2/LMP) stands for the nominal T-cell response to a viral antigen, and the HLA-A2-ve PBLs co-cultured with the Tyr369-377 pulsed T2 (T2/Tyr) for alloreactive T-cell response to an allogeneic antigen. The specificity of the expanded CTLs after the LTMLC was detected by their specific cytotoxicity and binding ability to specific pMHC-tetramer. An HLA-A2 restricted, HIV peptide (Gag77-85)was included for control. The cultural bulk of HLA-A2+ve PBLs with the T2/LMP showed an elevated specific cytotoxicity against the T2/LMP compared to that against the T2/HIV (26.52%±3.72% vs 7.01%±0.87%, P<0.001), and an increased frequency of binding to LMP-tetramer compared to that binding to HIV-tetramer (0.98%±0.33% vs 0.05%±0.01%, P=0.0014). The cultural bulk of HLA-A2-ve PBLs with the T2/Tyr showed a more active cytotoxicity against the T2/Tyr than that against T2/HIV (28.07%±2.58% vs 6.87%±0.01 %, P<0.001), and a higher frequency of binding to the Tyr-tetramer than that binding to the HIV-tetramer (0.88%±0.3% vs 0.06%±0.03%, P=0.0018). Our results indicate that the LTMLC is able to expand the viral antigen-specific CTLs as well as allogeneic antigen-specific CTLs. A relatively large proportion of alloreactive CTLs should be pMHC-specific, i.e., the specificity of the alloreactive lines depends on both the bound peptide and the
基金supported by the Francis Crick Institute(FC001099)which receives its core funding from Cancer Research UK,the UK Medical Research Council,and the Wellcome Trust.
文摘CD4^(+)T cells integrate well-defined signals from the T-cell receptor(TCR)(signal 1)and a host of costimulatory molecules(signal 2)to initiate clonal expansion and differentiation into diverse functional T helper(Th)subsets.However,our ability to guide the expansion of context-appropriate Th subsets by deploying these signals in vaccination remains limited.Using cell-based vaccines,we selectively amplified signal 1 by exclusive presentation of an optimized peptide:MHC II(pMHC II)complex in the absence of classic costimulation.Contrary to expectations,amplified signal 1 alone was strongly immunogenic and selectively expanded highaffinity TCR clonotypes,despite delivering intense TCR signals.In contrast to natural infection or standard vaccines,amplified signal 1,presented by a variety of professional and nonprofessional antigen-presenting cells(APCs),induced exclusively polyfunctional Th1 effector and memory cells,which protected against retroviral infection and tumor challenge,and expanded tumor-reactive CD4^(+)T cells otherwise rendered unresponsive in tumor-bearing hosts.Together,our findings uncover a default Th1 response to ample signal 1 and offer a means to selectively prime such protective responses by vaccination.
基金This research was supported in part by a grant-in-aid for scientific research from the Ministry of Education,Science,Sports,and Culture of Japan,by a grant from Human Science Foundation,and by a grantin-aid for AIDS research from the Ministry of Health,Labor,and Welfare of Japan.
文摘Untreated human immunodeficiency virus(HIV)infections usually lead to death from AIDS,although the rate of the disease progression varies widely among individuals.The cytotoxic T lymphocyte(CTL)response,which is restricted by highly polymorphic MHC class I alleles,plays a central role in controlling HIV replication.It is now recognized that the antiviral efficacy of CTLs at the single cell level is dependent on their antigen specificity and is important in determining the quality of host response to viruses so that the individual will remain asymptomatic.However,because of the extreme mutational plasticity of HIV,HIV-specific CTL responses are continuously and dynamically changing.In order to rationally design an effective vaccine,the questions as to what constitutes an effective antiviral CTL response and what characterizes a potent antigenic peptide to induce such responses are becoming highlighted as needing to be answered.
