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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

Comparison of antigenic repertoire and magnitude of HTNV-Gn/Gc-specific T-cell responses in patients with different severities.(A-B) Comparison of (A) the total magnitudes (y axis) of ex vivo ELISPOT IFN-γ T-cell responses to the overlapping peptide pools covering the HTNV-Gn/Gc, and (B) the number of single positive responding HTNV-Gn/Gc 15-mer T cell epitopes (y axis) at the acute stage between mild/moderate patients (n = 31) and severe/critical patients (n = 39) (x-axis). (C) The correlation between the total magnitude of T-cell responses specific to HTNV-Gn/Gc peptide pools and the number of HTNV-Gn/Gc T-cell epitopes recognized in HFRS patients. (D) Comparison of the recognized epitope number in four subgroups between mild/moderate and severe/critical HFRS patients. The subgroups were divided based on the different magnitude of the specific T-cell responses, including total spot-forming cells (SFC) 0–500, 501–1000, 1001–2000 and more than 2000. Each spot represents a single patient for A-D. (E-F) Comparison of the magnitude of the epitope-specific responses (y-axis) of CD4+ (E) or CD8+ (F) T cells at the acute stage between the two groups in 25 patients (x-axis). Each spot represents a single epitope for E-F. The magnitude of the response is represented as the SFC/106 PBMCs. The Wilcoxon rank sum test was used for statistical evaluation.
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ppat.1004788.g003: Comparison of antigenic repertoire and magnitude of HTNV-Gn/Gc-specific T-cell responses in patients with different severities.(A-B) Comparison of (A) the total magnitudes (y axis) of ex vivo ELISPOT IFN-γ T-cell responses to the overlapping peptide pools covering the HTNV-Gn/Gc, and (B) the number of single positive responding HTNV-Gn/Gc 15-mer T cell epitopes (y axis) at the acute stage between mild/moderate patients (n = 31) and severe/critical patients (n = 39) (x-axis). (C) The correlation between the total magnitude of T-cell responses specific to HTNV-Gn/Gc peptide pools and the number of HTNV-Gn/Gc T-cell epitopes recognized in HFRS patients. (D) Comparison of the recognized epitope number in four subgroups between mild/moderate and severe/critical HFRS patients. The subgroups were divided based on the different magnitude of the specific T-cell responses, including total spot-forming cells (SFC) 0–500, 501–1000, 1001–2000 and more than 2000. Each spot represents a single patient for A-D. (E-F) Comparison of the magnitude of the epitope-specific responses (y-axis) of CD4+ (E) or CD8+ (F) T cells at the acute stage between the two groups in 25 patients (x-axis). Each spot represents a single epitope for E-F. The magnitude of the response is represented as the SFC/106 PBMCs. The Wilcoxon rank sum test was used for statistical evaluation.

Mentions: After the ex vivo assessment of the T-cell responses against the HTNV-Gn/Gc, we divided the HFRS patients into two groups according to disease severity and compared their HTNV-Gn/Gc-specific immune responses. Among the 90 patients examined, T-cell responses against HTNV-Gn/Gc were detected in 31 of the 35 (88.6%) patients in the mild/moderate group compared with 39 of the 55 (70.9%) in the severe/critical group (Fisher’s exact chi-square test, P = 0.068). Importantly, although the breadth and magnitude of the HTNV-Gn/Gc-specific T-cell responses varied considerably among HFRS individuals, a comparison of the two groups (31 mild/moderate and 39 severe/critical) revealed a total SFC count (the sum of all responses to peptide pools), as an index of the total reactivity against HTNV-Gn/Gc, ranging from 135 to 4,911/106 PBMCs (median 881) for subjects in the mild/moderate group, was significantly higher than that observed for patients in the severe/critical group, with values ranging from 95 to 2,370/106 PBMCs (median 500) (P = 0.0068) (Fig 3A). Although the broad distribution of responses was similar in both groups, higher numbers of recognized HTNV-Gn/Gc peptides were observed in the mild/moderate group (mean 10; range 1–25) compared with severe/critical patients, who showed a relatively narrower repertoire directed against a smaller number of HTNV-Gn/Gc epitopes (mean 5; range 1–18) (P = 0.0010) (Fig 3B). We next analyzed the correlation between magnitude and breadth of the response specific to HTNV-Gn/Gc and found there was a positive association between the number of epitopes recognized and the total SFC/106 PBMCs of the T-cell responses specific to HTNV-Gn/Gc epitope pools in HFRS patients (P<0.0001, r = 0.482) (Fig 3C). Moreover, when dividing the patients into four subgroups according to the total SFC count (/106 PBMCs) including SFC 0–500, SFC 501–1000, SFC 1001–2000 and SFC greater than 2000, the comparison of the recognized epitope number showed a similar tendency that more epitopes are recognized in subjects with mild/moderate disease than that in severe/critical patients in each subgroup, especially in the subgroup with SFC 0–500 (P = 0.007) (Fig 3D). Therefore, this higher reactivity, including broader and stronger T-cell responses, was associated with mild rather than severe disease outcomes of HFRS. Consistent with the total T-cell response pattern against HTNV-Gn/Gc, a comparison of the responses targeting CD4+ or CD8+T-cell epitopes in two groups of 25 HFRS patients (12 mild/moderate and 13 severe/critical) showed similar results. A significant quantitative difference in the magnitude of both CD4+ and CD8+T-cell responses against each HTNV-Gn/Gc peptide was observed between the two groups. The number of SFC/106 cells was higher in the mild/moderate group (median 106, range 39–1,758 for CD4+T-cell responses and median 210, range 70–2,490 for CD8+T-cell responses) than that in severe/critical group (median 88, range 39–253 for CD4+T-cell responses and median 134, range 40–738 for CD8+T-cell responses) (P = 0.027 and P = 0.032 for CD4+ and CD8+T-cell responses, respectively) (Fig 3E-3F). In addition, although the difference was not statistically significant, we observed a wider breadth of both CD4+ and CD8+T-cell epitope responses in the mild/moderate group compared with that in severe/critical patients. To avoid the overlaps between the moderate and severe patients in all above comparisons, we separated the two combined groups into four clinical types as mentioned in Materials and Methods. The comparisons between the mild and critical patients showed similar results with the data between the mild/moderate and severe/critical patients (S1 Fig). The difference in total SFC/106 PBMC of the recognized epitope pools between the two ends of the patients’ spectrum was more marked (P = 0.0012) than that between the two combined groups (P = 0.0068). Collectively, HTNV-Gn/Gc could elicit robust T-cell immunity with extended epitopic breadth of Gn/Gc specificity. However, in contrast to subjects with mild/moderate HFRS, the responses in patients with severe/critical severity showed narrower antigenic repertoire and much weaker responses against HTNV-Gn/Gc, indicating that HTNV-Gn/Gc-specific T-cell responses would be functional against the HTNV infection during HFRS.


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)

Comparison of antigenic repertoire and magnitude of HTNV-Gn/Gc-specific T-cell responses in patients with different severities.(A-B) Comparison of (A) the total magnitudes (y axis) of ex vivo ELISPOT IFN-γ T-cell responses to the overlapping peptide pools covering the HTNV-Gn/Gc, and (B) the number of single positive responding HTNV-Gn/Gc 15-mer T cell epitopes (y axis) at the acute stage between mild/moderate patients (n = 31) and severe/critical patients (n = 39) (x-axis). (C) The correlation between the total magnitude of T-cell responses specific to HTNV-Gn/Gc peptide pools and the number of HTNV-Gn/Gc T-cell epitopes recognized in HFRS patients. (D) Comparison of the recognized epitope number in four subgroups between mild/moderate and severe/critical HFRS patients. The subgroups were divided based on the different magnitude of the specific T-cell responses, including total spot-forming cells (SFC) 0–500, 501–1000, 1001–2000 and more than 2000. Each spot represents a single patient for A-D. (E-F) Comparison of the magnitude of the epitope-specific responses (y-axis) of CD4+ (E) or CD8+ (F) T cells at the acute stage between the two groups in 25 patients (x-axis). Each spot represents a single epitope for E-F. The magnitude of the response is represented as the SFC/106 PBMCs. The Wilcoxon rank sum test was used for statistical evaluation.
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Related In: Results  -  Collection

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getmorefigures.php?uid=PMC4383613&req=5

ppat.1004788.g003: Comparison of antigenic repertoire and magnitude of HTNV-Gn/Gc-specific T-cell responses in patients with different severities.(A-B) Comparison of (A) the total magnitudes (y axis) of ex vivo ELISPOT IFN-γ T-cell responses to the overlapping peptide pools covering the HTNV-Gn/Gc, and (B) the number of single positive responding HTNV-Gn/Gc 15-mer T cell epitopes (y axis) at the acute stage between mild/moderate patients (n = 31) and severe/critical patients (n = 39) (x-axis). (C) The correlation between the total magnitude of T-cell responses specific to HTNV-Gn/Gc peptide pools and the number of HTNV-Gn/Gc T-cell epitopes recognized in HFRS patients. (D) Comparison of the recognized epitope number in four subgroups between mild/moderate and severe/critical HFRS patients. The subgroups were divided based on the different magnitude of the specific T-cell responses, including total spot-forming cells (SFC) 0–500, 501–1000, 1001–2000 and more than 2000. Each spot represents a single patient for A-D. (E-F) Comparison of the magnitude of the epitope-specific responses (y-axis) of CD4+ (E) or CD8+ (F) T cells at the acute stage between the two groups in 25 patients (x-axis). Each spot represents a single epitope for E-F. The magnitude of the response is represented as the SFC/106 PBMCs. The Wilcoxon rank sum test was used for statistical evaluation.
Mentions: After the ex vivo assessment of the T-cell responses against the HTNV-Gn/Gc, we divided the HFRS patients into two groups according to disease severity and compared their HTNV-Gn/Gc-specific immune responses. Among the 90 patients examined, T-cell responses against HTNV-Gn/Gc were detected in 31 of the 35 (88.6%) patients in the mild/moderate group compared with 39 of the 55 (70.9%) in the severe/critical group (Fisher’s exact chi-square test, P = 0.068). Importantly, although the breadth and magnitude of the HTNV-Gn/Gc-specific T-cell responses varied considerably among HFRS individuals, a comparison of the two groups (31 mild/moderate and 39 severe/critical) revealed a total SFC count (the sum of all responses to peptide pools), as an index of the total reactivity against HTNV-Gn/Gc, ranging from 135 to 4,911/106 PBMCs (median 881) for subjects in the mild/moderate group, was significantly higher than that observed for patients in the severe/critical group, with values ranging from 95 to 2,370/106 PBMCs (median 500) (P = 0.0068) (Fig 3A). Although the broad distribution of responses was similar in both groups, higher numbers of recognized HTNV-Gn/Gc peptides were observed in the mild/moderate group (mean 10; range 1–25) compared with severe/critical patients, who showed a relatively narrower repertoire directed against a smaller number of HTNV-Gn/Gc epitopes (mean 5; range 1–18) (P = 0.0010) (Fig 3B). We next analyzed the correlation between magnitude and breadth of the response specific to HTNV-Gn/Gc and found there was a positive association between the number of epitopes recognized and the total SFC/106 PBMCs of the T-cell responses specific to HTNV-Gn/Gc epitope pools in HFRS patients (P<0.0001, r = 0.482) (Fig 3C). Moreover, when dividing the patients into four subgroups according to the total SFC count (/106 PBMCs) including SFC 0–500, SFC 501–1000, SFC 1001–2000 and SFC greater than 2000, the comparison of the recognized epitope number showed a similar tendency that more epitopes are recognized in subjects with mild/moderate disease than that in severe/critical patients in each subgroup, especially in the subgroup with SFC 0–500 (P = 0.007) (Fig 3D). Therefore, this higher reactivity, including broader and stronger T-cell responses, was associated with mild rather than severe disease outcomes of HFRS. Consistent with the total T-cell response pattern against HTNV-Gn/Gc, a comparison of the responses targeting CD4+ or CD8+T-cell epitopes in two groups of 25 HFRS patients (12 mild/moderate and 13 severe/critical) showed similar results. A significant quantitative difference in the magnitude of both CD4+ and CD8+T-cell responses against each HTNV-Gn/Gc peptide was observed between the two groups. The number of SFC/106 cells was higher in the mild/moderate group (median 106, range 39–1,758 for CD4+T-cell responses and median 210, range 70–2,490 for CD8+T-cell responses) than that in severe/critical group (median 88, range 39–253 for CD4+T-cell responses and median 134, range 40–738 for CD8+T-cell responses) (P = 0.027 and P = 0.032 for CD4+ and CD8+T-cell responses, respectively) (Fig 3E-3F). In addition, although the difference was not statistically significant, we observed a wider breadth of both CD4+ and CD8+T-cell epitope responses in the mild/moderate group compared with that in severe/critical patients. To avoid the overlaps between the moderate and severe patients in all above comparisons, we separated the two combined groups into four clinical types as mentioned in Materials and Methods. The comparisons between the mild and critical patients showed similar results with the data between the mild/moderate and severe/critical patients (S1 Fig). The difference in total SFC/106 PBMC of the recognized epitope pools between the two ends of the patients’ spectrum was more marked (P = 0.0012) than that between the two combined groups (P = 0.0068). Collectively, HTNV-Gn/Gc could elicit robust T-cell immunity with extended epitopic breadth of Gn/Gc specificity. However, in contrast to subjects with mild/moderate HFRS, the responses in patients with severe/critical severity showed narrower antigenic repertoire and much weaker responses against HTNV-Gn/Gc, indicating that HTNV-Gn/Gc-specific T-cell responses would be functional against the HTNV infection during HFRS.

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