Altered Expression of CD4, CD54, CD62L, and CCR5 in Primary Lymphocytes Productively Infected with the Human Immunodeficiency Virus

Abstract

Infection of T cells with HIV-1 induces loss of CD4 and HLA class I from the cell surface. In the present article we have investigated whether changes in expression of other cell surface molecules could be related to HIV infection. To detect HIV-infected cells at the single-cell level, peripheral blood lymphocytes were infected in vitro with HIV-HSA, a reporter virus encoding the murine heat-stable antigen. Expression of HSA on activated primary lymphocytes was an efficient indicator of productive infection. Expression of the majority of the cell surface proteins studied was unaffected by HIV infection (HLA class I, II, CD11a, CD18, CD25, CD27, CD28, CD29, CD30, CD31, CD38, CD44, CD45R0, CD49d, CD57, CD94, CD95, and CXCR4). However, phenotypic changes specific to the productively infected cells were detected. Expression of the CD4 molecule was progressively lost and this was closely associated with loss of CD62L expression, a molecule involved in T cell homing into the lymph nodes. By contrast, T cells productively infected with this T-tropic reporter virus were enriched for CD54, and for CCR5, the main coreceptor for M-tropic viruses. Given the roles of CD62L, CD54, and CCR5 in lymphocyte trafficking, these results suggest that cells productively infected with HIV might have altered homing patterns in vivo.

Productive infection of double-negative T cells with HIVin vivo

“…Although we can neither rule out direct infection of some DN T cells nor exclude that some HIV-positive DN cells derive from infected thymocytes, the simplest explanation for the presence of HIV-positive DN T cells in vivo is CD4 down-regulation occurring after infection of peripheral CD4 ϩ precursors. If HIVpositive DN cells are former CD4 ϩ cells, one would expect continued expression of CD4 mRNA, as previously shown in PBL, infected in vitro with a reporter virus (7). We tested for the presence of CD4 mRNA in CD4, CD8, and DN subsets sorted from HIV-positive patients and found only small amounts of The data presented (Fig.…”

“…Down-regulation of CD4 from the cell surface has been well documented in transformed T cell lines infected in the laboratory (17) and in primary lymphocytes infected with a reporter virus (6,7). If this down-regulation occurs in vivo, one would expect to find HIV-infected DN T cells as described in this study, the first comprehensive analysis of HIV infection in this subset.…”

“…HIV RNA in T Cell Subsets. RNA was isolated, and cDNA was synthesized (7). cDNA was diluted to obtain substrate cDNA levels corresponding to the indicated cell number equivalents.…”

“…However, evidence for CD4 down-regulation in HIV-positive subjects is still lacking and most prior work was performed with transformed cell lines with unknown relevance in vivo. CD4 down-regulation occurs in primary human peripheral blood lymphocytes (PBL) infected with a reporter virus (6,7). For example, in PBL infected with HIV-HSA (HIV with a murine heat stable antigen reporter gene), HSA ϩ cells progressively lost CD4 expression, while maintaining high levels of CD4 mRNA and unaltered levels of T cell receptor (TCR) and CD8 expression (7).…”

“…CD4 down-regulation occurs in primary human peripheral blood lymphocytes (PBL) infected with a reporter virus (6,7). For example, in PBL infected with HIV-HSA (HIV with a murine heat stable antigen reporter gene), HSA ϩ cells progressively lost CD4 expression, while maintaining high levels of CD4 mRNA and unaltered levels of T cell receptor (TCR) and CD8 expression (7). Therefore, infected double-negative (DN) T cells are generated from CD4 ϩ precursors.…”