HIV-1 infectivity of human T cells in a human/murine chimeric fetal thymic organ culture system.

Human cord blood (HuCB) can colonize a murine fetal thymus organ culture (FTOC) and generate phenotypically immature (CD4+ CD8+) and mature (CD4+ CD8-; CD4- CD8+) T cells. We have used this model system to demonstrate that the human T cells that develop in this culture system can be infected with HIV-1. A cytopathic and non-cytopathic patient isolate of HIV-1 were used to infect FTOC established using C.B-17 or NOD/LtSz.scid/scid strain fetal thymic lobes colonized with HuCB. At 13-15 days after infection, FTOC were placed in co-culture with human PHA-blasts. These co-cultures demonstrated the presence of replicating HIV-1. Few human CD45+ cells were detectable in the thymic lobes that were infected with HIV-1, while high numbers of human CD45+ T cells were present in the uninfected cultures. These results demonstrate the cytopathicity of HIV-1 on human T lymphocytes that have developed in a HuCB colonized FTOC system.