HIV Infection of the BS-1 Human Stroma Cell Line: Effect on Murine Hematopoiesis

Abstract BS-1, a stroma cell line derived from normal human bone marrow, can support the growth of murine erythroid (BFU-E), granulocyte-macrophage (CFU-GM), and megakaryocyte (CFU-Meg) progenitor cells in a short-term in vitro coculture system. Exposure of BS-1 cell to the human immunodeficiency virus (HIV) prior to coculture results in a marked reduction in the stroma cell's ability to support murine BFU-E and CFU-GM. The effect of HIV on the BS-1 cell's hematopoietic support function (HSF) is dependent on the multiplicity of infection (m.o.i.). BS-1 stimulation of CFU-GM is significantly impaired at m.o.i. values ranging from 10 to 0.1, whereas its support of BFU-E colony formation is inhibited at m.o.i. values of 10 and 1. No effect of HIV on the BS-1 cell's HSF is observed with further log dilutions of virus. The HIV-mediated suppression of the BS-1 cell's ability to support hematopoiesis is neutralized by a monoclonal antibody (titers ranging from 1:10 to 1:50) to the Gp160 surface antigen of the virus. Suppression of BS-1 cell's HSF is again observed with log dilution (>1:100) of the antibody, HIV suppression of the BS-1 cell's HSF correlates with replication of the virus. P24 antigen levels of 150 pG/ml are measured as early as Day 6 postinfection and rise to 360 pG/ml by Day 16 of culture. The results suggest that HIV may impair normal hematopoiesis by infecting the stroma cells of the bone marrow microenvironment and compromising their role as accessory cells in supporting the proliferation and differentiation of hematopoietic progenitor cells.