Up-regulation by feline interleukin-4 and down-regulation by feline interferon-gamma of major histocompatibility complex class II on cat B-lymphocytes.
Interleukin-4 (IL-4) exhibits numerous biological and immunoregulatory functions on B- and T-lymphocytes, monocytes, and dendritic cells in both mice and humans. In the present study, we show that IL-4 also has a regulatory function in the cat species. Cells transfected with IL-4 DNA expressed a biologically active protein as demonstrated by the up-regulation of MHC class II molecules on B-lymphocytes (CD21(+)) in a flow cytometric assay. Increased levels of MHC class II expression on CD21(+) cells were seen in 11 out of 12 cats (p<0.05). In addition, 12 out of 12 cats showed up-regulation of MHC class II on CD21(-) cells, mainly consisting of T-lymphocytes (p<0.05). In contrast, concanavalin A (ConA)-induced culture supernatant from peripheral blood mononuclear cells (PBMCs) containing high levels of interferon-gamma (IFN-gamma) transcripts induced down-regulation of MHC class II molecules on CD21(+) cells of all samples (p<0.05). Variable results were observed for CD21(-) cells incubated with ConA-conditioned medium (p=0.71). The nature of the cytokine(s) responsible for these effects remains to be determined. However, the fact that down-regulation of MHC class II molecules on B cells occurred in all cats tested suggests that IFN-gamma may be involved. These data provide further insight into the mechanism by which MHC class II expression is regulated in feline lymphocytes, and suggest that the Th1/Th2 paradigm is also present in the cat.
Clinical Laboratory, Faculty of Veterinary Medicine, University of Zurich, 8057 Zurich, Switzerland. mgomes@vetclinics.unizh.ch
M A
MA
Gomes-Keller
R
R
Nunez
M
M
Schroff
D
D
Oswald
B J
BJ
Willett
H
H
Lutz
D000818:Animals; D001402:B-Lymphocytes / Q000276:immunology* / Q000378:metabolism; D002415:Cats / Q000276:immunology*; D002478:Cells, Cultured; D003208:Concanavalin A / Q000276:immunology; D017077:Culture Media, Conditioned; D015536:Down-Regulation; D005260:Female; D005434:Flow Cytometry; D000949:Histocompatibility Antigens Class II / Q000032:analysis / Q000096:biosynthesis* / Q000276:immunology; D007371:Interferon-gamma / Q000235:genetics / Q000276:immunology*; D015847:Interleukin-4 / Q000235:genetics / Q000276:immunology*; D008297:Male; D016133:Polymerase Chain Reaction; D017464:Receptors, Complement 3d / Q000032:analysis; D014158:Transcription, Genetic; D014162:Transfection; D015854:Up-Regulation
D017077:Culture Media, Conditioned; D000949:Histocompatibility Antigens Class II; D017464:Receptors, Complement 3d; D003208:Concanavalin A; D015847:Interleukin-4; D007371:Interferon-gamma