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Consequences of HLA‐associated mutations in HIV‐1 subtype C Nef on HLA‐I downregulation ability
Author(s) -
Mann Jaclyn K.,
Rajkoomar Erasha,
Jin Steven W.,
Mkhize Qiniso,
Baiyegunhi Omolara,
Mbona Pholisiwe,
Brockman Mark A.,
Ndung'u Thumbi
Publication year - 2020
Publication title -
journal of medical virology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.782
H-Index - 121
eISSN - 1096-9071
pISSN - 0146-6615
DOI - 10.1002/jmv.25676
Subject(s) - ctl* , downregulation and upregulation , biology , mutation , human leukocyte antigen , virology , immunology , cd8 , flow cytometry , cytotoxic t cell , genetics , immune system , antigen , gene , in vitro
Abstract Identification of CD8+ T lymphocyte (CTL) escape mutations that compromise the pathogenic functions of the Nef protein may be relevant for an HIV‐1 attenuation‐based vaccine. Previously, HLA‐associated mutations 102H, 105R, 108D, and 199Y were individually statistically associated with decreased Nef‐mediated HLA‐I downregulation ability in a cohort of 298 HIV‐1 subtype C infected individuals. In the present study, these mutations were introduced by site‐directed mutagenesis into different patient‐derived Nef sequence backgrounds of high similarity to the consensus C Nef sequence, and their ability to downregulate HLA‐I was measured by flow cytometry in a CEM‐derived T cell line. A substantial negative effect of 199Y on HLA‐I downregulation and Nef expression was observed, while 102H and 105R displayed negative effects on HLA‐I downregulation ability and Nef expression to a lesser extent. The total magnitude of CTL responses in individuals harboring the 199Y mutation was lower than those without the mutation, although this was not statistically significant. Overall, a modest positive relationship between Nef‐mediated HLA‐I downregulation ability and total magnitude of CTL responses was observed, suggesting that there is a higher requirement for HLA‐I downregulation with increased CTL pressure. These results highlight a region of Nef that could be targeted by vaccine‐induced CTL to reduce HLA‐I downregulation and maximize CTL efficacy.