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Hantaan virus infection induces both Th1 and ThGranzyme B+ cell immune responses that associated with viral control and clinical outcome in humans.

Ma Y, Yuan B, Zhuang R, Zhang Y, Liu B, Zhang C, Zhang Y, Yu H, Yi J, Yang A, Jin B - PLoS Pathog. (2015)

Bottom Line: Here, based on the T-cell epitopes mapped on HTNV glycoprotein, we studied the effects and characteristics of CD4(+)T-cell responses in determining the outcome of hemorrhagic fever with renal syndrome.Individuals with milder disease outcomes showed broader epitopes targeted and stronger CD4(+)T-cell responses against HTNV glycoproteins compared with more severe patients.The host defense mediated by CD4(+)T cells may through the inducing antiviral condition of the host cells and cytotoxic effect of ThGranzyme B+ cells.

View Article: PubMed Central - PubMed

Affiliation: Department of Immunology, the Fourth Military Medical University, Xi'an, China.

ABSTRACT
Hantaviruses infection causing severe emerging diseases with high mortality rates in humans has become public health concern globally. The potential roles of CD4(+)T cells in viral control have been extensively studied. However, the contribution of CD4(+)T cells to the host response against Hantaan virus (HTNV) infection remains unclear. Here, based on the T-cell epitopes mapped on HTNV glycoprotein, we studied the effects and characteristics of CD4(+)T-cell responses in determining the outcome of hemorrhagic fever with renal syndrome. A total of 79 novel 15-mer T-cell epitopes on the HTNV glycoprotein were identified, among which 20 peptides were dominant target epitopes. Importantly, we showed the presence of both effective Th1 responses with polyfunctional cytokine secretion and ThGranzyme B(+) cell responses with cytotoxic mediators production against HTNV infection. The HTNV glycoprotein-specific CD4(+)T-cell responses inversely correlated with the plasma HTNV RNA load in patients. Individuals with milder disease outcomes showed broader epitopes targeted and stronger CD4(+)T-cell responses against HTNV glycoproteins compared with more severe patients. The CD4(+)T cells characterized by broader antigenic repertoire, stronger polyfunctional responses, better expansion capacity and highly differentiated effector memory phenotype(CD27-CD28-CCR7-CD45RA-CD127(hi)) would elicit greater defense against HTNV infection and lead to much milder outcome of the disease. The host defense mediated by CD4(+)T cells may through the inducing antiviral condition of the host cells and cytotoxic effect of ThGranzyme B+ cells. Thus, these findings highlight the efforts of CD4(+)T-cell immunity to HTNV control and provide crucial information to better understand the immune defense against HTNV infection.

No MeSH data available.


Related in: MedlinePlus

The magnitude of granzyme B production and cytotoxic capacity of HTNV-Gn/Gc-specific CD4+T cells.(A) Comparison of the SFC/106 cells of granzyme B secreted by CD4+T cells specific to HTNV-Gn/Gc in ELISPOT assay between mild/moderate patients and severe/critical individuals in acute phase of HFRS. (B) The kinetics of specific lysis of peptides-pulsed target cells by the HTNV-Gn/Gc-specific CD4+T-cell population assessed by in vitro cell-mediated cytotoxicity assay. The CD4+T cells isolated from the PBMCs of the HFRS patients were used as effector cells, and the Epstein Barr Virus (EBV) transformed autologous B lymphoblastic cell line (B-LCL) or MHC class Ⅱ partial matched B-LCL of each patient pulsed with HTNV-Gn/Gc peptides were used as target cells. The effector-to-target ratios included 200:1, 100:1, 50:1, 20:1, 10:1 and 5:1. The dark spots and the circles represent the mean lysis percentage of CD4+T cells from mild/moderate and severe/critical patients, respectively to kill the HTNV-Gn/Gc peptides-pulsed target cells. The triangles represent the mean lysis percentage of CD4+T cells from all the patients to kill no peptide-pulsed target cells. The comparison of lysis percentages between the mild/moderate and severe/critical groups at each effector-to-target ratio were showed as *P<0.05, **P<0.01, and ns, not significant. The Wilcoxon rank sum test was used for statistical evaluation.
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ppat.1004788.g006: The magnitude of granzyme B production and cytotoxic capacity of HTNV-Gn/Gc-specific CD4+T cells.(A) Comparison of the SFC/106 cells of granzyme B secreted by CD4+T cells specific to HTNV-Gn/Gc in ELISPOT assay between mild/moderate patients and severe/critical individuals in acute phase of HFRS. (B) The kinetics of specific lysis of peptides-pulsed target cells by the HTNV-Gn/Gc-specific CD4+T-cell population assessed by in vitro cell-mediated cytotoxicity assay. The CD4+T cells isolated from the PBMCs of the HFRS patients were used as effector cells, and the Epstein Barr Virus (EBV) transformed autologous B lymphoblastic cell line (B-LCL) or MHC class Ⅱ partial matched B-LCL of each patient pulsed with HTNV-Gn/Gc peptides were used as target cells. The effector-to-target ratios included 200:1, 100:1, 50:1, 20:1, 10:1 and 5:1. The dark spots and the circles represent the mean lysis percentage of CD4+T cells from mild/moderate and severe/critical patients, respectively to kill the HTNV-Gn/Gc peptides-pulsed target cells. The triangles represent the mean lysis percentage of CD4+T cells from all the patients to kill no peptide-pulsed target cells. The comparison of lysis percentages between the mild/moderate and severe/critical groups at each effector-to-target ratio were showed as *P<0.05, **P<0.01, and ns, not significant. The Wilcoxon rank sum test was used for statistical evaluation.

Mentions: We next set out to determine whether the granzyme B-secreting CD4+T cells could kill the HTNV-Gn/Gc peptide pools-pulsed target cells. Firstly, ex vivo granzyme B enzyme-linked immunospot (ELISPOT) assay showed that the HTNV-Gn/Gc epitope peptide pools could stimulate CD4+T cells of HFRS patients to produce granzyme B with the average magnitude of 450 SFC/106 cells (range, 21–1,226) (S6 Fig, n = 11 for mild/moderate and severe/critical patients, respectively). The comparison between the two groups showed that the magnitude of granzyme B-producing CD4+T-cell response was stronger in mild/moderate patients than that in severe/critical individuals (median 712, range 215–1,226 SFC/106 cells for mild/moderate group and median 131, range 21–872 SFC/106 cells for severe/critical group, P = 0.0181) (Fig 6A). Second, the biological cytolytic function of CD4+T cells was determined by the cytotoxic assay, in which the CD4+T cells of HFRS patients could lyse HTNV-Gn/Gc peptides-pulsed autologous or MHC class Ⅱ partial matched B lymphoblastic cell lines (B-LCLs) with the average percentage of 22.63 (range, 10.92–45.93) at effector-to-target cell ratio of 200:1. Moreover, we also observed that the percentages of cytotoxicity in mild/moderate group seems to be higher than that in severe/critical group at effector-to-target cell ratio of 200:1(P = 0.0002), 100:1(P = 0.0002) and 50:1 (P = 0.0229) (Fig 6B). The cytotoxic capacity of each patient was showed in S7 Fig (n = 7 for mild/moderate and n = 9 for severe/critical patients). Collectively, these results suggested that ThGzmB+ cell subset might participate in the immune response against HTNV infection through the production of granzyme B and cell-mediated cytolytic function during the early stages of the disease, defining a specific CD4+T cell functional phenotype for HTNV control.


Hantaan virus infection induces both Th1 and ThGranzyme B+ cell immune responses that associated with viral control and clinical outcome in humans.

Ma Y, Yuan B, Zhuang R, Zhang Y, Liu B, Zhang C, Zhang Y, Yu H, Yi J, Yang A, Jin B - PLoS Pathog. (2015)

The magnitude of granzyme B production and cytotoxic capacity of HTNV-Gn/Gc-specific CD4+T cells.(A) Comparison of the SFC/106 cells of granzyme B secreted by CD4+T cells specific to HTNV-Gn/Gc in ELISPOT assay between mild/moderate patients and severe/critical individuals in acute phase of HFRS. (B) The kinetics of specific lysis of peptides-pulsed target cells by the HTNV-Gn/Gc-specific CD4+T-cell population assessed by in vitro cell-mediated cytotoxicity assay. The CD4+T cells isolated from the PBMCs of the HFRS patients were used as effector cells, and the Epstein Barr Virus (EBV) transformed autologous B lymphoblastic cell line (B-LCL) or MHC class Ⅱ partial matched B-LCL of each patient pulsed with HTNV-Gn/Gc peptides were used as target cells. The effector-to-target ratios included 200:1, 100:1, 50:1, 20:1, 10:1 and 5:1. The dark spots and the circles represent the mean lysis percentage of CD4+T cells from mild/moderate and severe/critical patients, respectively to kill the HTNV-Gn/Gc peptides-pulsed target cells. The triangles represent the mean lysis percentage of CD4+T cells from all the patients to kill no peptide-pulsed target cells. The comparison of lysis percentages between the mild/moderate and severe/critical groups at each effector-to-target ratio were showed as *P<0.05, **P<0.01, and ns, not significant. The Wilcoxon rank sum test was used for statistical evaluation.
© Copyright Policy
Related In: Results  -  Collection

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Show All Figures
getmorefigures.php?uid=PMC4383613&req=5

ppat.1004788.g006: The magnitude of granzyme B production and cytotoxic capacity of HTNV-Gn/Gc-specific CD4+T cells.(A) Comparison of the SFC/106 cells of granzyme B secreted by CD4+T cells specific to HTNV-Gn/Gc in ELISPOT assay between mild/moderate patients and severe/critical individuals in acute phase of HFRS. (B) The kinetics of specific lysis of peptides-pulsed target cells by the HTNV-Gn/Gc-specific CD4+T-cell population assessed by in vitro cell-mediated cytotoxicity assay. The CD4+T cells isolated from the PBMCs of the HFRS patients were used as effector cells, and the Epstein Barr Virus (EBV) transformed autologous B lymphoblastic cell line (B-LCL) or MHC class Ⅱ partial matched B-LCL of each patient pulsed with HTNV-Gn/Gc peptides were used as target cells. The effector-to-target ratios included 200:1, 100:1, 50:1, 20:1, 10:1 and 5:1. The dark spots and the circles represent the mean lysis percentage of CD4+T cells from mild/moderate and severe/critical patients, respectively to kill the HTNV-Gn/Gc peptides-pulsed target cells. The triangles represent the mean lysis percentage of CD4+T cells from all the patients to kill no peptide-pulsed target cells. The comparison of lysis percentages between the mild/moderate and severe/critical groups at each effector-to-target ratio were showed as *P<0.05, **P<0.01, and ns, not significant. The Wilcoxon rank sum test was used for statistical evaluation.
Mentions: We next set out to determine whether the granzyme B-secreting CD4+T cells could kill the HTNV-Gn/Gc peptide pools-pulsed target cells. Firstly, ex vivo granzyme B enzyme-linked immunospot (ELISPOT) assay showed that the HTNV-Gn/Gc epitope peptide pools could stimulate CD4+T cells of HFRS patients to produce granzyme B with the average magnitude of 450 SFC/106 cells (range, 21–1,226) (S6 Fig, n = 11 for mild/moderate and severe/critical patients, respectively). The comparison between the two groups showed that the magnitude of granzyme B-producing CD4+T-cell response was stronger in mild/moderate patients than that in severe/critical individuals (median 712, range 215–1,226 SFC/106 cells for mild/moderate group and median 131, range 21–872 SFC/106 cells for severe/critical group, P = 0.0181) (Fig 6A). Second, the biological cytolytic function of CD4+T cells was determined by the cytotoxic assay, in which the CD4+T cells of HFRS patients could lyse HTNV-Gn/Gc peptides-pulsed autologous or MHC class Ⅱ partial matched B lymphoblastic cell lines (B-LCLs) with the average percentage of 22.63 (range, 10.92–45.93) at effector-to-target cell ratio of 200:1. Moreover, we also observed that the percentages of cytotoxicity in mild/moderate group seems to be higher than that in severe/critical group at effector-to-target cell ratio of 200:1(P = 0.0002), 100:1(P = 0.0002) and 50:1 (P = 0.0229) (Fig 6B). The cytotoxic capacity of each patient was showed in S7 Fig (n = 7 for mild/moderate and n = 9 for severe/critical patients). Collectively, these results suggested that ThGzmB+ cell subset might participate in the immune response against HTNV infection through the production of granzyme B and cell-mediated cytolytic function during the early stages of the disease, defining a specific CD4+T cell functional phenotype for HTNV control.

Bottom Line: Here, based on the T-cell epitopes mapped on HTNV glycoprotein, we studied the effects and characteristics of CD4(+)T-cell responses in determining the outcome of hemorrhagic fever with renal syndrome.Individuals with milder disease outcomes showed broader epitopes targeted and stronger CD4(+)T-cell responses against HTNV glycoproteins compared with more severe patients.The host defense mediated by CD4(+)T cells may through the inducing antiviral condition of the host cells and cytotoxic effect of ThGranzyme B+ cells.

View Article: PubMed Central - PubMed

Affiliation: Department of Immunology, the Fourth Military Medical University, Xi'an, China.

ABSTRACT
Hantaviruses infection causing severe emerging diseases with high mortality rates in humans has become public health concern globally. The potential roles of CD4(+)T cells in viral control have been extensively studied. However, the contribution of CD4(+)T cells to the host response against Hantaan virus (HTNV) infection remains unclear. Here, based on the T-cell epitopes mapped on HTNV glycoprotein, we studied the effects and characteristics of CD4(+)T-cell responses in determining the outcome of hemorrhagic fever with renal syndrome. A total of 79 novel 15-mer T-cell epitopes on the HTNV glycoprotein were identified, among which 20 peptides were dominant target epitopes. Importantly, we showed the presence of both effective Th1 responses with polyfunctional cytokine secretion and ThGranzyme B(+) cell responses with cytotoxic mediators production against HTNV infection. The HTNV glycoprotein-specific CD4(+)T-cell responses inversely correlated with the plasma HTNV RNA load in patients. Individuals with milder disease outcomes showed broader epitopes targeted and stronger CD4(+)T-cell responses against HTNV glycoproteins compared with more severe patients. The CD4(+)T cells characterized by broader antigenic repertoire, stronger polyfunctional responses, better expansion capacity and highly differentiated effector memory phenotype(CD27-CD28-CCR7-CD45RA-CD127(hi)) would elicit greater defense against HTNV infection and lead to much milder outcome of the disease. The host defense mediated by CD4(+)T cells may through the inducing antiviral condition of the host cells and cytotoxic effect of ThGranzyme B+ cells. Thus, these findings highlight the efforts of CD4(+)T-cell immunity to HTNV control and provide crucial information to better understand the immune defense against HTNV infection.

No MeSH data available.


Related in: MedlinePlus