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Identification of immunodominant CD4-restricted epitopes co-located with antibody binding sites in individuals vaccinated with ALVAC-HIV and AIDSVAX B/E.

Ratto-Kim S, de Souza MS, Currier JR, Karasavvas N, Sidney J, Rolland M, Valencia-Micolta A, Madnote S, Sette A, Nitayaphan S, Pitisuttuthum P, Kaewkungwal J, Rerks-Ngarm S, O'Connell R, Michael N, Robb ML, Marovich M, Kim JH - PLoS ONE (2015)

Bottom Line: Non-transformed Env-specific T cell lines established from RV144 vaccinees were used to determine the fine epitope mapping of the V2 and C1 responses and the HLA class II restriction.Data showed that there are two CD4+ epitopes contained within the V2 loop: one encompassing the α4β7 integrin binding site (AA179-181) and the other nested between two previously described genetic sieve signatures (AA169, AA181).There was no correlation between the frequencies of CD4+ fine epitope responses and binding antibody.

View Article: PubMed Central - PubMed

Affiliation: United States Military HIV Research Program, Walter Reed Army Institute of Research, Silver Spring, MD, 20910, United States of America.

ABSTRACT
We performed fine epitope mapping of the CD4+ responses in the ALVAC-HIV-AIDSVAX B/E prime-boost regimen in the Thai Phase III trial (RV144). Non-transformed Env-specific T cell lines established from RV144 vaccinees were used to determine the fine epitope mapping of the V2 and C1 responses and the HLA class II restriction. Data showed that there are two CD4+ epitopes contained within the V2 loop: one encompassing the α4β7 integrin binding site (AA179-181) and the other nested between two previously described genetic sieve signatures (AA169, AA181). There was no correlation between the frequencies of CD4+ fine epitope responses and binding antibody.

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Env-specific CD4+ T cell lines that showed positive responses to either p16, p31 or p32, were tested in a modified ELISpot against a panel of truncated peptides based on the full sequence of p16 (gp120 C1 region), p31 and p32 (gp120 V2 region).Addition of Q (aa 170) increase % positive to about 60% and 100% response is reached when K (aa169) is added. Position 180 (D) is also critical as the number of responders increased from about 30% to 100%. This position is extremely conserved and forms the α4β7-binding motif. Amino acid at position 176 (F) is important for antibody binding. HAL aa sequence is within a highly conserved region of the V2 loop. Sequences below the graph depict where the mapped epitope lies. The amino acids within boxes were sieve signatures described by Rolland et al. [12].
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pone.0115582.g002: Env-specific CD4+ T cell lines that showed positive responses to either p16, p31 or p32, were tested in a modified ELISpot against a panel of truncated peptides based on the full sequence of p16 (gp120 C1 region), p31 and p32 (gp120 V2 region).Addition of Q (aa 170) increase % positive to about 60% and 100% response is reached when K (aa169) is added. Position 180 (D) is also critical as the number of responders increased from about 30% to 100%. This position is extremely conserved and forms the α4β7-binding motif. Amino acid at position 176 (F) is important for antibody binding. HAL aa sequence is within a highly conserved region of the V2 loop. Sequences below the graph depict where the mapped epitope lies. The amino acids within boxes were sieve signatures described by Rolland et al. [12].

Mentions: We defined the fine epitope specificity using a series of truncated peptides that span the sequences of the V2 peptides and C1 peptide. Reagents to study the fine epitope specificity for p79 were not available at the time of the study. Fig. 2 and S1 Table shows the frequency of the T cell lines with V2 and C1 specificity. These experiments identified two epitopes in V2 overlapping by 6 aa but not cross-reactive as individuals that recognized peptide 31 (p31) did not recognize peptide 32 (p32) despite 11 aa of overlap. A peptide truncation set spanning peptide 16 (p16) revealed a possible shorter epitope that was not contained in the adjacent overlapping peptide 17. Interestingly, the CD4+ T cell epitopes defined in the V2 region contained or fell in between the V2 K169Q and I181L sieve mutations in RV144 vaccine recipients who subsequently became HIV infected [12] (Fig. 2 and S1 Table).


Identification of immunodominant CD4-restricted epitopes co-located with antibody binding sites in individuals vaccinated with ALVAC-HIV and AIDSVAX B/E.

Ratto-Kim S, de Souza MS, Currier JR, Karasavvas N, Sidney J, Rolland M, Valencia-Micolta A, Madnote S, Sette A, Nitayaphan S, Pitisuttuthum P, Kaewkungwal J, Rerks-Ngarm S, O'Connell R, Michael N, Robb ML, Marovich M, Kim JH - PLoS ONE (2015)

Env-specific CD4+ T cell lines that showed positive responses to either p16, p31 or p32, were tested in a modified ELISpot against a panel of truncated peptides based on the full sequence of p16 (gp120 C1 region), p31 and p32 (gp120 V2 region).Addition of Q (aa 170) increase % positive to about 60% and 100% response is reached when K (aa169) is added. Position 180 (D) is also critical as the number of responders increased from about 30% to 100%. This position is extremely conserved and forms the α4β7-binding motif. Amino acid at position 176 (F) is important for antibody binding. HAL aa sequence is within a highly conserved region of the V2 loop. Sequences below the graph depict where the mapped epitope lies. The amino acids within boxes were sieve signatures described by Rolland et al. [12].
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4321833&req=5

pone.0115582.g002: Env-specific CD4+ T cell lines that showed positive responses to either p16, p31 or p32, were tested in a modified ELISpot against a panel of truncated peptides based on the full sequence of p16 (gp120 C1 region), p31 and p32 (gp120 V2 region).Addition of Q (aa 170) increase % positive to about 60% and 100% response is reached when K (aa169) is added. Position 180 (D) is also critical as the number of responders increased from about 30% to 100%. This position is extremely conserved and forms the α4β7-binding motif. Amino acid at position 176 (F) is important for antibody binding. HAL aa sequence is within a highly conserved region of the V2 loop. Sequences below the graph depict where the mapped epitope lies. The amino acids within boxes were sieve signatures described by Rolland et al. [12].
Mentions: We defined the fine epitope specificity using a series of truncated peptides that span the sequences of the V2 peptides and C1 peptide. Reagents to study the fine epitope specificity for p79 were not available at the time of the study. Fig. 2 and S1 Table shows the frequency of the T cell lines with V2 and C1 specificity. These experiments identified two epitopes in V2 overlapping by 6 aa but not cross-reactive as individuals that recognized peptide 31 (p31) did not recognize peptide 32 (p32) despite 11 aa of overlap. A peptide truncation set spanning peptide 16 (p16) revealed a possible shorter epitope that was not contained in the adjacent overlapping peptide 17. Interestingly, the CD4+ T cell epitopes defined in the V2 region contained or fell in between the V2 K169Q and I181L sieve mutations in RV144 vaccine recipients who subsequently became HIV infected [12] (Fig. 2 and S1 Table).

Bottom Line: Non-transformed Env-specific T cell lines established from RV144 vaccinees were used to determine the fine epitope mapping of the V2 and C1 responses and the HLA class II restriction.Data showed that there are two CD4+ epitopes contained within the V2 loop: one encompassing the α4β7 integrin binding site (AA179-181) and the other nested between two previously described genetic sieve signatures (AA169, AA181).There was no correlation between the frequencies of CD4+ fine epitope responses and binding antibody.

View Article: PubMed Central - PubMed

Affiliation: United States Military HIV Research Program, Walter Reed Army Institute of Research, Silver Spring, MD, 20910, United States of America.

ABSTRACT
We performed fine epitope mapping of the CD4+ responses in the ALVAC-HIV-AIDSVAX B/E prime-boost regimen in the Thai Phase III trial (RV144). Non-transformed Env-specific T cell lines established from RV144 vaccinees were used to determine the fine epitope mapping of the V2 and C1 responses and the HLA class II restriction. Data showed that there are two CD4+ epitopes contained within the V2 loop: one encompassing the α4β7 integrin binding site (AA179-181) and the other nested between two previously described genetic sieve signatures (AA169, AA181). There was no correlation between the frequencies of CD4+ fine epitope responses and binding antibody.

Show MeSH