Macrophage tropism of feline leukemia virus (FeLV) of subgroup-C and increased production of tumor necrosis factor-alpha by FeLV-infected macrophages.
Erythroid aplasia is induced in cats by feline leukemia virus (FeLV) of subgroup C but not by FeLV of subgroup A. In an investigation of the role of macrophages in FeLV-C-induced diseases, the concentrations of FeLV and tumor necrosis factor-alpha (TNF-alpha) were compared between feline peritoneal macrophages incubated with FeLV of subgroup A or C. FeLV of both subgroups infected macrophages, but expression of FeLV-C was 21-fold higher than FeLV-A in peritoneal macrophages (P = .004). The supernatants of FeLV-C-inoculated macrophage cultures contained significantly higher levels of TNF-alpha (70 +/- 14 U/mL) at 72 hours postincubation compared with FeLV-A-inoculated (38 +/- 8 U/mL) and uninoculated (31 +/- 8 U/mL) cultures. Moreover, a positive correlation was shown between cell-associated FeLV surface glycoprotein gp70 and TNF-alpha expression in FeLV-C-infected macrophages by immunofluorescence (r = .6; P = .001), measured with a computer-assisted, laser-based digital imaging system. The addition of TNF-alpha to a uniform population of FeLV-infected cells (feline embryonic fibroblasts) caused an enhancement of viral expression (P < .05). These results indicate that FeLV-C has tropism for macrophages, FeLV expression is positively correlated with TNF-alpha expression in macrophages, and TNF-alpha enhances FeLV replication in fibroblasts. We suggest that FeLV-C infection of macrophages and secretion of TNF-alpha may be important in hematopoietic suppression in FeLV-C-infected cats.
Department of Veterinary Pathobiology, College of Veterinary Medicine, Ohio State University, Columbus.
K N
KN
Khan
G J
GJ
Kociba
M L
ML
Wellman
D000818:Animals; D002415:Cats; D002478:Cells, Cultured; D005347:Fibroblasts / Q000187:drug effects / Q000382:microbiology / Q000502:physiology; D006801:Humans; D007700:Kinetics; D005256:Leukemia Virus, Feline / Q000145:classification / Q000187:drug effects / Q000502:physiology*; D008264:Macrophages / Q000382:microbiology* / Q000502:physiology*; D011994:Recombinant Proteins / Q000494:pharmacology; D013997:Time Factors; D014409:Tumor Necrosis Factor-alpha / Q000096:biosynthesis* / Q000494:pharmacology
D011994:Recombinant Proteins; D014409:Tumor Necrosis Factor-alpha