ZDV delays but does not prevent the transmission of MAIDS by LP-BM5 MuLV-infected macrophage-monocytes.

LP-BM5 MuLV infection of monocyte-macrophages (MM cells) and the ability of MM cells infected with this murine oncornavirus complex to transmit murine acquired immune deficiency syndrome (MAIDS) were assessed. Adherent cells expressing Mac-1 antigen (Mac-1+) were isolated from the peritoneum of infected C57BL/6 mice at weekly intervals postinoculation. A small percentage of MM cells was infected by 7 days after inoculation with LP-BM5 MuLV and virus production could be detected in MM cells throughout the course of disease. MAIDS could be induced in naive C57BL/6 mice by i.p. injection of 0.5-3 x 10(5) MM cells derived from infected mice as early as 8 weeks postinfection. When 3 x 10(5) cells (300 infectious centers) were injected, the progression of disease was similar to that seen after inoculation with a known virus pool (log10 5.78 XC pfu/ml). Treatment with zidovudine (ZDV) at 1 mg/ml in drinking water delayed disease progression if started 24 h prior to inoculation of MM cells and given continuously.