Could CD4 Capture by CD8+ T Cells Play a Role in HIV Spreading?

CD8(+) T cells have been shown to capture plasma membrane fragments from target cells expressing their cognate antigen, a process termed "trogocytosis". Here, we report that human CD4, the Human Immunodeficiency Virus (HIV) receptor, can be found among the proteins transferred by trogocytosis. CD4 is expressed in a correct orientation after its capture by CD8(+) T cells as shown by its detection using conformational antibodies and its ability to allow HIV binding on recipient CD8(+) T cells. Although we could not find direct evidence for infection of CD8(+) T cells having captured CD4 by HIV, CD4 was virologically functional on these cells as it conferred on them the ability to undergo syncytia formation induced by HIV-infected MOLT-4 cells. Our results show that acquisition of CD4 by CD8(+) T cells via trogocytosis could play a previously unappreciated role for CD8(+) T cells in HIV spreading possibly without leading to their infection.