Immunosuppression by Moloney leukemia virus: lack of correlation between virus replication and the immunosuppressive effect.
Young adult mice were infected with 10(4) plaque-forming units (PFU) or Moloney murine leukemia virus M-MuLV. Two different virus preparations were used: a) M-MuLV obtained from serial passage in mice [animal passage (AP)] and b) tissue culture (TC)-grown virus harvested after three in vitro passages of the AP M-MuLV in fibroblasts. Replication of TC and AP M-MuLV in spleen cells was determined by an infectious center (IC) assay at 1 and 2 weeks after the infection. Immune responsiveness of spleen cells was evaluated in challenge with sheep red blood cells (SRBC) and subsequent enumeration of antibody plaque-forming cells (PFC). TC M-MuLV replicated faster in the spleen than did AP M-MuLV and reached about 10- to 100-fold higher titers. However, the response of anti-SRBC PFC, suppressed to the same degree in the spleens of mice infected with TC or AP virus, was from 10 to 50% of the control response. A comparison of virus replication with the anti-SRBC response in aliquots from the same spleens showed no correlation between virus IC and antibody PFC. Both TC and AP M-MuLV induced the expression of virus-specific, cell membrane antigen on spleen cells. These findings indicated a divergence between virus replication on the one hand and the immunosuppressive effect and the cell membrane alteration on the other.
D000818:Animals; D000956:Antigens, Viral; D005260:Female; D006462:Hemolytic Plaque Technique; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D008979:Moloney murine leukemia virus / Q000254:growth & development*; D013154:Spleen / Q000276:immunology / Q000382:microbiology; D013950:Thymus Gland / Q000276:immunology; D014412:Tumor Virus Infections / Q000276:immunology*; D014776:Virus Cultivation; D014779:Virus Replication
D000956:Antigens, Viral