A novel glycoprotein expressed on sheep T and B lymphocytes is involved in a T cell activation pathway.
We have produced a new mouse mAb that identifies a sheep T cell activation Ag. The mAb B5-5 is specific for low m.w. components on nearly all sheep thymocytes and peripheral T and B lymphocytes but does not label immature B cells in Peyer's patches or germinal centers. After cross-linking of target structures either directly by plastic-bound mAb or indirectly using anti-Ig reagents, peripheral T cells, but not thymocytes or peripheral B cells, were activated. IL-2 was secreted by T cells after cross-linking and activation was strongly augmented in the presence of PMA. The addition of soluble B5-5 mAb to mitogen-stimulated cultures of sheep lymphocytes resulted in a suppression of PHA responses and augmentation of PWM responses and had a variable effect on Con A responses but had no effect on LPS- or protein A-induced proliferation. When added to alloantigen-stimulated cultures, B5-5 augmented the proliferative response. The B5-5 membrane component consists of 14- to 19-kDa glycoproteins but the banding patterns obtained during SDS-PAGE analysis of 125I-labeled Ag differed between thymocytes, peripheral T cells, and peripheral B cells. On the basis of its range of expression on lymphoid cells and known biochemical and functional properties, we conclude that the B5-5 component on sheep lymphocytes is different from T cell activation Ag in other species.
Hein
W R
WR
Basel Institute for Immunology, Switzerland.
McClure
S
S
Beya
M F
MF
Dudler
L
L
Trnka
Z
Z
D000818:Animals; D000911:Antibodies, Monoclonal / Q000276:immunology; D000945:Antigens, Differentiation, T-Lymphocyte / Q000276:immunology; D000954:Antigens, Surface / Q000276:immunology*; D001402:B-Lymphocytes / Q000276:immunology*; D003432:Cross-Linking Reagents; D007124:Immunoenzyme Techniques; D007376:Interleukin-2 / Q000502:physiology; D008213:Lymphocyte Activation; D008221:Lymphoid Tissue / Q000276:immunology; D008562:Membrane Glycoproteins / Q000276:immunology*; D008934:Mitogens; D012756:Sheep / Q000276:immunology*; D012995:Solubility; D013601:T-Lymphocytes / Q000276:immunology*; D018127:Tumor Necrosis Factor Receptor Superfamily, Member 7
D000911:Antibodies, Monoclonal; D000945:Antigens, Differentiation, T-Lymphocyte; D000954:Antigens, Surface; D003432:Cross-Linking Reagents; D007376:Interleukin-2; D008562:Membrane Glycoproteins; D008934:Mitogens; D018127:Tumor Necrosis Factor Receptor Superfamily, Member 7