Identification of the avian homologues of mammalian CD4 and CD8 antigens.
Two mAb were produced against chicken T cells. The CT4 antibody precipitated a polypeptide of Mr 64,000 under both reducing and non-reducing conditions. The CT8 antibody precipitated a molecule of Mr 63,000 under non-reducing conditions and polypeptide chains of Mr 34,000 under reducing conditions, suggesting that the CT8 molecule is a disulfide-linked homodimer. Tissue distribution studies by immunofluorescence revealed that the CT4 and CT8 Ag were expressed by the majority of thymocytes and by subpopulations of CT3+ cells in peripheral tissues. The CT4 reactive molecule was found on approximately 70% of thymocytes, 10% splenocytes, and 45% of lymphoid cells in blood. The CT8 reactive molecule was expressed on approximately 80% of thymocytes, 50% of spleen cells, and 15% of blood lymphocytes. Two-color immunofluorescence indicated that the CT4 and CT8 Ag were expressed together on most thymocytes and on mutually exclusive subsets of cells in the spleen and blood. Ontogenic studies revealed a sharp increase in the frequencies of CT4+ and CT8+ cells in the thymus between days 13 and 16 embryonic life. Both CT4 and CT8 antibodies inhibited PHA- and Con A-induced proliferative responses of splenocytes, and the degree of inhibition correlated with the frequencies of CT4+ and CT8+ lymphoblasts. Treatment of spleen cells with CT4 antibody and inhibited PWM-induced IL-2 production, and removal of CT8+ cells inhibited the cytolytic activity induced by allogeneic lymphocyte stimulation. Macrophages did not express detectable CT4 reactivity. These results suggest that the CD4 and CD8 molecules and their tissue-restricted patterns of expression are highly conserved in birds and mammals.
Chan
M M
MM
Department of Pediatrics, University of Alabama, Birmingham 35294.
Chen
C L
CL
Ager
L L
LL
Cooper
M D
MD
D000818:Animals; D000945:Antigens, Differentiation, T-Lymphocyte / Q000032:analysis*; D002645:Chickens / Q000276:immunology*; D006412:Hematopoietic Stem Cells / Q000032:analysis; D006801:Humans; D008221:Lymphoid Tissue / Q000032:analysis; D008222:Lymphokines / Q000096:biosynthesis; D051379:Mice; D008807:Mice, Inbred BALB C; D008934:Mitogens; D010641:Phenotype; D013045:Species Specificity; D013601:T-Lymphocytes / Q000032:analysis / Q000145:classification* / Q000378:metabolism; D013602:T-Lymphocytes, Cytotoxic / Q000145:classification; D013950:Thymus Gland / Q000196:embryology / Q000276:immunology
D000945:Antigens, Differentiation, T-Lymphocyte; D008222:Lymphokines; D008934:Mitogens