Platelet-bound HIV infects CD4⁺T cells through platelet–T-cell complex formation. CD4⁺ T cells were isolated from HIV⁻ donors and differentiated using anti-CD3/CD28 beads and IL-2. Platelets from viremic cART-naive donors were treated with anti-CD62P or IgG control antibody and then cocultured with differentiated T cells. Flow cytometry was performed by staining for CD4 and CD61. (A) Platelet–T-cell complexes were then detected by flow cytometry using antibody specific for CD4 and CD61. Mean fluorescence intensity (MFI) of CD61 was used on CD4 gated cells as a measure of platelet–T-cell complex formation at 24 hours. Correlations were calculated using a Pearson correlation. (B) HIV-1 p24 was quantified by enzyme-linked immunosorbent assay (ELISA) in cell-free culture supernatants 72 hours after coculture (n = 3). Significance was determined using a paired Student t test. (C) Platelets from HIV⁻ donors were incubated with HIV-1 IIIB and then treated with anti-CD62P or IgG antibodies, as above, prior to coculture with differentiated CD4⁺ T cells. CD4⁺ CD61 MFI was used to measure platelet–T-cell complex formation. (D) HIV-1 p24 was quantified by ELISA in cell-free supernatant at 72 hours postcoculture (n = 4). (E) Platelets from HIV⁻ donors were treated with aspirin, R406, anti–DC-SIGN antibodies, or DMSO control prior to treatment with TRAP6 or vehicle control and subsequent incubation with HIV-1 IIIB prior to coculture with differentiated CD4⁺ T cells. Cocultures were treated with cART or supernatant from the third platelet wash as negative controls. HIV p24 was quantified by ELISA in cell-free supernatant at 72 hours after coculture (n = 4).