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Understanding CD8 + T-cell responses toward the native and alternate HLA-A * 02:01-restricted WT1 epitope

View Article: PubMed Central - PubMed

ABSTRACT

Ry: The Wilms' tumor 1 (WT1) antigen is expressed in solid and hematological malignancies, but not healthy tissues, making it a promising target for cancer immunotherapies. Immunodominant WT1 epitopes, the native HLA-A2/WT1126-134 (MFPNAPYL) (HLA-A2/RMFPNAPYL epitope (WT1A)) and its modified variant MFPNAPYL (HLA-A2/YMFPNAPYL epitope (WT1B)), can induce WT1-specific CD8+ T cells, although WT1B is more stably bound to HLA-A*02:01. Here, to further determine the benefits of those two targets, we assessed the naive precursor frequencies; immunogenicity and cross-reactivity of CD8+ T cells directed toward these two WT1 epitopes. Ex vivo naive WT1A- and WT1B-specific CD8+ T cells were detected in healthy HLA-A*02:01+ individuals with comparable precursor frequencies (1 in 105–106) to other naive CD8+ T-cell pools (for example, A2/HIV-Gag77-85), but as expected, ~100 × lower than those found in memory populations (influenza, A2/M158-66; EBV, A2/BMLF1280-288). Importantly, only WT1A-specific naive precursors were detected in HLA-A2.1 mice. To further assess the immunogenicity and recruitment of CD8+ T cells responding to WT1A and WT1B, we immunized HLA-A2.1 mice with either peptide. WT1A immunization elicited numerically higher CD8+ T-cell responses to the native tumor epitope following re-stimulation, although both regimens produced functionally similar responses toward WT1A via cytokine analysis and CD107a expression. Interestingly, however, WT1B immunization generated cross-reactive CD8+ T-cell responses to WT1A and could be further expanded by WT1A peptide revealing two distinct populations of single- and cross-reactive WT1A+CD8+ T cells with unique T-cell receptor-αβ gene signatures. Therefore, although both epitopes are immunogenic, the clinical benefits of WT1B vaccination remains debatable and perhaps both peptides may have separate clinical benefits as treatment targets.

No MeSH data available.


WT1B vaccination induces cross-reactive WT1A-specific CD8+ T cells. Seven days following the fourth injection, dual WT1A/WT1B-tetramer staining ex vivo was performed in one experiment on iLN cells from four WT1A-vaccinated (a) and four WT1B-vaccinated mice (b). Individual staining profiles for each mouse are shown using co-stain 3 and co-stain 4. Percentages of tetramer+CD8+ T cells from WT1A-vaccinated (c) and WT1B-vaccinated (d) mice are gated on total CD8+ T cells (mean±s.d. bars are shown).
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fig3: WT1B vaccination induces cross-reactive WT1A-specific CD8+ T cells. Seven days following the fourth injection, dual WT1A/WT1B-tetramer staining ex vivo was performed in one experiment on iLN cells from four WT1A-vaccinated (a) and four WT1B-vaccinated mice (b). Individual staining profiles for each mouse are shown using co-stain 3 and co-stain 4. Percentages of tetramer+CD8+ T cells from WT1A-vaccinated (c) and WT1B-vaccinated (d) mice are gated on total CD8+ T cells (mean±s.d. bars are shown).

Mentions: We next addressed whether there was any cross-reactivity between the WT1A- or WT1B-specific CD8+ T-cell responses induced by either vaccination. We assessed this by co-staining with both WT1A- and WT1B-tetramers using WT1A-tetramer R-phycoerythrin (PE)/WT1B-tetramer allophycocyanin (APC) (co-stain 3) or WT1A-tetramer APC/WT1B-tetramer PE (co-stain 4). In WT1A/CpG-vaccinated mice (Figure 3a), there was very little cross-reactivity detected toward the WT1B-tetramer, and was only observed in one animal (mouse 2) using the more robust tetramer combination for visualizing cross-reactive dual-tetramer+ CD8+ T cells (co-stain 3).


Understanding CD8 + T-cell responses toward the native and alternate HLA-A * 02:01-restricted WT1 epitope
WT1B vaccination induces cross-reactive WT1A-specific CD8+ T cells. Seven days following the fourth injection, dual WT1A/WT1B-tetramer staining ex vivo was performed in one experiment on iLN cells from four WT1A-vaccinated (a) and four WT1B-vaccinated mice (b). Individual staining profiles for each mouse are shown using co-stain 3 and co-stain 4. Percentages of tetramer+CD8+ T cells from WT1A-vaccinated (c) and WT1B-vaccinated (d) mice are gated on total CD8+ T cells (mean±s.d. bars are shown).
© Copyright Policy - open-access
Related In: Results  -  Collection

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getmorefigures.php?uid=PMC5382434&req=5

fig3: WT1B vaccination induces cross-reactive WT1A-specific CD8+ T cells. Seven days following the fourth injection, dual WT1A/WT1B-tetramer staining ex vivo was performed in one experiment on iLN cells from four WT1A-vaccinated (a) and four WT1B-vaccinated mice (b). Individual staining profiles for each mouse are shown using co-stain 3 and co-stain 4. Percentages of tetramer+CD8+ T cells from WT1A-vaccinated (c) and WT1B-vaccinated (d) mice are gated on total CD8+ T cells (mean±s.d. bars are shown).
Mentions: We next addressed whether there was any cross-reactivity between the WT1A- or WT1B-specific CD8+ T-cell responses induced by either vaccination. We assessed this by co-staining with both WT1A- and WT1B-tetramers using WT1A-tetramer R-phycoerythrin (PE)/WT1B-tetramer allophycocyanin (APC) (co-stain 3) or WT1A-tetramer APC/WT1B-tetramer PE (co-stain 4). In WT1A/CpG-vaccinated mice (Figure 3a), there was very little cross-reactivity detected toward the WT1B-tetramer, and was only observed in one animal (mouse 2) using the more robust tetramer combination for visualizing cross-reactive dual-tetramer+ CD8+ T cells (co-stain 3).

View Article: PubMed Central - PubMed

ABSTRACT

Ry: The Wilms' tumor 1 (WT1) antigen is expressed in solid and hematological malignancies, but not healthy tissues, making it a promising target for cancer immunotherapies. Immunodominant WT1 epitopes, the native HLA-A2/WT1126-134 (MFPNAPYL) (HLA-A2/RMFPNAPYL epitope (WT1A)) and its modified variant MFPNAPYL (HLA-A2/YMFPNAPYL epitope (WT1B)), can induce WT1-specific CD8+ T cells, although WT1B is more stably bound to HLA-A*02:01. Here, to further determine the benefits of those two targets, we assessed the naive precursor frequencies; immunogenicity and cross-reactivity of CD8+ T cells directed toward these two WT1 epitopes. Ex vivo naive WT1A- and WT1B-specific CD8+ T cells were detected in healthy HLA-A*02:01+ individuals with comparable precursor frequencies (1 in 105–106) to other naive CD8+ T-cell pools (for example, A2/HIV-Gag77-85), but as expected, ~100 × lower than those found in memory populations (influenza, A2/M158-66; EBV, A2/BMLF1280-288). Importantly, only WT1A-specific naive precursors were detected in HLA-A2.1 mice. To further assess the immunogenicity and recruitment of CD8+ T cells responding to WT1A and WT1B, we immunized HLA-A2.1 mice with either peptide. WT1A immunization elicited numerically higher CD8+ T-cell responses to the native tumor epitope following re-stimulation, although both regimens produced functionally similar responses toward WT1A via cytokine analysis and CD107a expression. Interestingly, however, WT1B immunization generated cross-reactive CD8+ T-cell responses to WT1A and could be further expanded by WT1A peptide revealing two distinct populations of single- and cross-reactive WT1A+CD8+ T cells with unique T-cell receptor-αβ gene signatures. Therefore, although both epitopes are immunogenic, the clinical benefits of WT1B vaccination remains debatable and perhaps both peptides may have separate clinical benefits as treatment targets.

No MeSH data available.