Distinct patterns of Bcl-2 expression occur in R5- and X4-tropic HIV-1-producing lymphoid tissue cells infected ex vivo

AIDS Res Hum Retroviruses. 2015 Mar;31(3):298-304. doi: 10.1089/aid.2014.0155. Epub 2014 Oct 29.

Abstract

Most HIV-1 replication occurs in secondary lymphoid tissues in T cells within B cell follicles. Mechanisms underlying the accumulation of HIV-1-producing cells at these sites are not understood. Antiapoptotic proteins such as Bcl-2 could promote follicular CD4(+) T cell survival, contributing to sustained virus production. Tonsils obtained from subjects without known HIV infection were disaggregated and analyzed for Bcl-2 expression in follicular (CXCR5(+)) and extrafollicular (CXCR5(-)) CD3(+)CD4(+) cells by flow cytometry. Additional tonsil cells were cultured with phytohemagglutinin (PHA) and interleukin-2 (IL-2) for 2 days, infected with either CCR5(R5) or CXCR4-tropic (X4) GFP reporter viruses, and analyzed for Bcl-2 expression. In freshly disaggregated CD3(+)CD4(+) tonsil cells, mean florescence intensity (MFI) for Bcl-2 was higher in CXCR5(+) (median, 292) compared to CXCR5(-) cells (median, 194; p=0.001). Following in vitro stimulation with PHA and IL-2, Bcl-2 MFI was higher in both CXCR5(+) cells (median, 757; p=0.03) and CXCR5(-) cells (median, 884; p=0.002) in uninfected cultures compared to freshly isolated tonsil cells. Bcl-2 MFI was higher in GFP(+)CD3(+)CD8(-) R5-producing cells (median, 554) than in X4-producing cells (median, 393; p=0.02). Bcl-2 MFI was higher in R5-producing CXCR5(+) cells (median, 840) compared to all other subsets including R5-producing CXCR5(-) cells (median, 524; p=0.04), X4-producing CXCR5(+) cells (median, 401; p=0.02), and X4-producing CXCR5(-) cells (median, 332; p=0.008). Bcl-2 expression is elevated in R5 HIV-1-producing CXCR5(+) T cells in vitro, which may contribute to propagation of R5 virus in B cell follicles in vivo.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Adolescent
  • CD4-Positive T-Lymphocytes / chemistry
  • CD4-Positive T-Lymphocytes / virology*
  • Child
  • Child, Preschool
  • Female
  • Gene Expression Profiling
  • HIV-1 / growth & development*
  • Humans
  • Immunophenotyping
  • Lymphoid Tissue / pathology*
  • Male
  • Proto-Oncogene Proteins c-bcl-2 / biosynthesis*
  • Receptors, CXCR4 / analysis*
  • Receptors, CXCR5 / analysis*
  • Receptors, HIV / analysis

Substances

  • CXCR4 protein, human
  • CXCR5 protein, human
  • Proto-Oncogene Proteins c-bcl-2
  • Receptors, CXCR4
  • Receptors, CXCR5
  • Receptors, HIV