Analysis of the phenotype and phagocytic activity of monocytes/macrophages from cattle infected with the bovine leukaemia virus.
The bovine leukaemia virus (BLV) is a retrovirus that infects mainly B lymphocytes of cattle, but proviral DNA can also be isolated from monocytes/macrophages. This study investigated the effect of BLV infection on surface antigens on freshly isolated peripheral blood monocytes and cultured monocyte-derived macrophages, with and without lipopolysaccharide (LPS) stimulation. The effect of BLV infection on phagocytic activity of CD14+ monocytes was also assessed. The percentage of monocytes expressing the surface antigens CD11b, CD32 (FcgammaRII), MHC class II and the surface antigen recognised by mAb DH59B were increased in BLV-positive cattle. In contrast, expression intensity of all markers was low in samples from BLV-positive cattle. CD14+ monocytes from BLV-positive cattle showed less Fcgamma-receptor-mediated phagocytosis compared to monocytes from BLV-negative cattle. After 7 days in culture, there was evidence for shedding/downregulation of surface antigens on monocyte-derived macrophages, in particular on cells from BLV-positive cattle. LPS stimulation decreased the percentage of cells expressing the measured markers in monocyte-derived macrophages taken from BLV-negative cattle, but not in cultures derived from BLV-positive cattle. The results provide further evidence for an altered function of monocytes and macrophages in BLV-infected cattle.
Werling
D
D
Institute for Animal Science, Physiology and Animal Husbandry, Swiss Federal Institute of Technology, Zürich.
Howard
C J
CJ
Niederer
E
E
Straub
O C
OC
Saalmüller
A
A
Langhans
W
W
D000818:Animals; D000911:Antibodies, Monoclonal; D015703:Antigens, CD / Q000276:immunology; D002417:Cattle / Q000276:immunology*; D002478:Cells, Cultured; D016583:Enzootic Bovine Leukosis / Q000276:immunology*; D005434:Flow Cytometry / Q000662:veterinary; D000949:Histocompatibility Antigens Class II / Q000276:immunology; D016130:Immunophenotyping / Q000662:veterinary; D001909:Leukemia Virus, Bovine / Q000276:immunology*; D008070:Lipopolysaccharides / Q000494:pharmacology; D008213:Lymphocyte Activation / Q000187:drug effects / Q000276:immunology; D008264:Macrophages / Q000276:immunology*; D009000:Monocytes / Q000276:immunology*; D010587:Phagocytosis / Q000502:physiology*
D000911:Antibodies, Monoclonal; D015703:Antigens, CD; D000949:Histocompatibility Antigens Class II; D008070:Lipopolysaccharides