In vitro infection of Hofbauer cells with a monocyte-tropic strain of HIV-1

Abstract

Summary In order to further understand the mechanisms of HIV transmission from mother to child, the susceptibility of Hofbauer cells to the monocyte-tropic strain HIV-1Ba-L was tested in vitro. Hofbauer cells were obtained from normal full term placentae after perfusion of two lobules, following the procedure of Uren et al. (1985). Cells isolated from this procedure were cultured on T-25 flasks with RPMI 20% fetal bovine serum and antibiotics. Characterization of these cells following overnight adherence indicated that 60% of the cells were positive for the macrophage antibody HAM56. After five days 93% of the cells were phagocytic and 85% were nonspecific esterase positive. Immunohistochemical analysis with macrophage specific antibodies indicated that 78% were Hofbauer cells. After 5–6 days in culture, 1×107 cells were inoculated with the monocyte-tropic strain HIVBa-L. Virus production was monitored in culture supernatants at different intervals by a p24 assay. There was a ten or greater fold increase of p24 within 3 weeks of culture. Parallel studies on HIVBa-L infected umbilical cord and adult monocytes showed a similar increase. Infection with the lymphocyte-tropic strain HIV/LAV revealed that Hofbauer cells were more susceptible than adult and cord blood macrophages.