Cytomegalovirus (CMV) Epitope–Specific CD4+ T Cells Are Inflated in HIV+ CMV+ Subjects

CO Abana, MA Pilkinton, S Gaudieri… - The Journal of …, 2017 - journals.aai.org
CO Abana, MA Pilkinton, S Gaudieri, A Chopra, WJ McDonnell, C Wanjalla, L Barnett…
The Journal of Immunology, 2017journals.aai.org
Select CMV epitopes drive life-long CD8+ T cell memory inflation, but the extent of CD4
memory inflation is poorly studied. CD4+ T cells specific for human CMV (HCMV) are
elevated in HIV+ HCMV+ subjects. To determine whether HCMV epitope–specific CD4+ T
cell memory inflation occurs during HIV infection, we used HLA-DR7 (DRB1* 07: 01)
tetramers loaded with the glycoprotein B DYSNTHSTRYV (DYS) epitope to characterize
circulating CD4+ T cells in coinfected HLA-DR7+ long-term nonprogressor HIV subjects with …
Abstract
Select CMV epitopes drive life-long CD8+ T cell memory inflation, but the extent of CD4 memory inflation is poorly studied. CD4+ T cells specific for human CMV (HCMV) are elevated in HIV+ HCMV+ subjects. To determine whether HCMV epitope–specific CD4+ T cell memory inflation occurs during HIV infection, we used HLA-DR7 (DRB1* 07: 01) tetramers loaded with the glycoprotein B DYSNTHSTRYV (DYS) epitope to characterize circulating CD4+ T cells in coinfected HLA-DR7+ long-term nonprogressor HIV subjects with undetectable HCMV plasma viremia. DYS-specific CD4+ T cells were inflated among these HIV+ subjects compared with those from an HIV− HCMV+ HLA-DR7+ cohort or with HLA-DR7–restricted CD4+ T cells from the HIV-coinfected cohort that were specific for epitopes of HCMV phosphoprotein-65, tetanus toxoid precursor, EBV nuclear Ag 2, or HIV gag protein. Inflated DYS-specific CD4+ T cells consisted of effector memory or effector memory–RA+ subsets with restricted TCRβ usage and nearly monoclonal CDR3 containing novel conserved amino acids. Expression of this near-monoclonal TCR in a Jurkat cell–transfection system validated fine DYS specificity. Inflated cells were polyfunctional, not senescent, and displayed high ex vivo levels of granzyme B, CX 3 CR1, CD38, or HLA-DR but less often coexpressed CD38+ and HLA-DR+. The inflation mechanism did not involve apoptosis suppression, increased proliferation, or HIV gag cross-reactivity. Instead, the findings suggest that intermittent or chronic expression of epitopes, such as DYS, drive inflation of activated CD4+ T cells that home to endothelial cells and have the potential to mediate cytotoxicity and vascular disease.
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