Endothelial Cells Promote Human Immunodeficiency Virus Replication in Nondividing Memory T Cells via Nef-, Vpr-, and T-Cell Receptor-Dependent Activation of NFAT

Endothelial Cell Stimulation Overcomes Restriction and Promotes Productive and Latent HIV-1 Infection of Resting CD4 + T Cells

“…This study confirms and extends initial studies by Choi et al (32,33). We confirmed that (i) EC stimulation dramatically enhances productive HIV infection of resting CD4 ϩ T cells, (ii) such infected T cells remained in a resting phenotype, and (iii) among these infected resting T cells, memory T cells were preferentially infected rather than naive T cells.…”

“…T cells were distinguished from EC by forward and side scatter gating, as they were much smaller and less granular than EC. We found no infection of EC, consistent with the results of Choi et al (32,33). We also infected resting T cells alone (R) as well as anti-CD3/CD28 antibody (CD3/28)-activated T cells (ACT) as controls.…”

“…Since we found untreated EC to be similar to IFN-␥-treated EC in promoting productive infection of resting CD4 ϩ T cells, we performed additional experiments to examine the interaction of T cells with EC that had not been stimulated with IFN-␥. Choi et al have previously reported (32,33) that resting CD4 ϩ T cells can be infected by HIV-1 after being cocultured with EC ϩ but remain in a resting state. We examined cell activation markers CD25, CD69, and HLA-DR using flow cytometry various days postinfection as well as GFP levels.…”

“…Choi et al (32,33) showed that the interactions between endothelial cells and T cells required cell-cell contact and were dependent upon MHC class II and CD58 on the endothelial cells. However, signals through T cell receptor (TCR)-MHC and CD2-CD58 were not sufficient in inducing HIV infection of resting T cells, and soluble factors were implicated.…”

“…We first established the endothelial cell-T cell coculture system and infected the resting CD4 ϩ T cells with a reporter HIV in which a portion of the envelope gene was replaced with enhanced GFP (EGFP) (NL43-dE-GFP [37]), as illustrated in (in vivo EC do express MHC class II) (Fig. 1B), as the expression of MHC class II on EC is thought to enhance HIV infection of resting T cells (32,33). Resting CD4 ϩ T cells were purified from healthy donors and cocultured with endothelial cells treated with IFN-␥ (EC ϩ ) or endothelial cells without IFN-␥ treatment (EC Ϫ ) for 1 day.…”