Impaired thymopoietic potential of immature CD3(-)CD4(+)CD8(-) T cell precursors from SIV-infected rhesus monkeys

Immature thymocyte subpopulations were examined for their capacity to diffe rentiate in a newly developed xenogeneic monkey-mouse fetal thymus organ cu lture (FTOC) system. We provide evidence for impaired precursor function of CD3(-)CD4(+)CD8(-) thymocytes after in vivo infection with SIVmac251 as in dicated by a reduced cell number per FTOC and a lower percentage of thymocy tes with more mature phenotypes. Addition of recombinant SIV glycoprotein 1 20 (rgp120) also resulted in a dose-dependent impairment of T cell maturati on in FTOC. The data suggest that in patients infected with HIV, T cell mat uration and thus replenishment of peripheral pools may be compromised as a result of intrathymic infection or circulating viral gp120.