CD4 + T cells from HIV-1 patients with impaired Th1 effector responses to Mycobacterium tuberculosis exhibit diminished histone and nucleoprotein signatures

Abstract

HIV+ patients have an increased risk for tuberculosis disease despite clinical management with ARTs. We established a culture model of Mtb-infection in PBMCs from HIV+ PPD+ donors on suppressive ART (median 6.4years) with negligible viral loads (median<50copies/mL) and stable CD4+ T cell counts (517cells/mm^3). We observed that HIV+ patient lymphocytes harbored a recruitment defect to Mtb-infected monocytes. To investigate these immune defects on a per cell basis, purified CD4+ T cells from HIV patients were assessed by label-free quantification protein mass spectrometry. CD4+ T cells from HIV patients displayed diminished nucleoprotein levels – notably of histone variant H2a.Z and ribonucleoprotein A1. Only within healthy donors, transcriptional regulatory histone variant H2a.Z expression was correlated to the extent of IFN-γ induction upon Mtb-infection. Our findings may explain why HIV patients exhibit prolonged immune cell dysfunction despite suppressive ART, and implicate a per cell defect of CD4+ T cells.