Characterization of a cell surface-expressed disulfide-linked dimer involved in murine T cell activation.
We have produced a hamster mAb, H1.2F3, which was derived by immunization with a murine TCR-gamma delta + epidermal T cell line. H1.2F3 immunoprecipitates a cell surface-expressed disulfide-linked dimer that has a m.w. of 85,000 under non-reducing conditions and consists of subunits of 35,000 to 39,000 m.w. This dimer is distinct from the CD3-associated TCR-gamma delta complex (CD3/TCR), inasmuch as H1.2F3 does not co-precipitate or co-modulate with the CD3/TCR complex and recognizes an Ag with a single-peptide backbone of 22,000 m.w. after N-Glycanase treatment. H1.2F3 is weakly reactive with a small percentage of cells from unfractionated thymus, spleen, or lymph node, but reactivity with both T and B lymphocytes is markedly enhanced by a brief period of stimulation with Con A or PMA in vitro. This enhancement requires de novo protein synthesis. Enhanced expression of the H1.2F3 Ag can also be induced in vivo by injection of Con A or anti-CD3. H1.2F3 is a potent stimulator of T, but not B, cell proliferation in the presence of PMA and FcR-bearing accessory cells. These functional and biochemical studies strongly suggest that the Ag recognized by H1.2F3 is the murine homologue of the human CD28 Ag recognized by mAb 9.3.
Yokoyama
W M
WM
Laboratory of Immunology, National Institute of Allergy and Infectious Diseases, Bethesda, MD 20892.
Koning
F
F
Kehn
P J
PJ
Pereira
G M
GM
Stingl
G
G
Coligan
J E
JE
Shevach
E M
EM
D000375:Aging; D000818:Animals; D000911:Antibodies, Monoclonal / Q000096:biosynthesis / Q000502:physiology; D000938:Antigen-Presenting Cells / Q000276:immunology; D000954:Antigens, Surface / Q000276:immunology / Q000302:isolation & purification*; D006224:Cricetinae; D004220:Disulfides; D008213:Lymphocyte Activation; D051379:Mice; D008809:Mice, Inbred C3H; D008970:Molecular Weight; D011487:Protein Conformation; D013329:Structure-Activity Relationship; D013601:T-Lymphocytes / Q000276:immunology* / Q000378:metabolism / Q000502:physiology; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology; D018127:Tumor Necrosis Factor Receptor Superfamily, Member 7
D000911:Antibodies, Monoclonal; D000954:Antigens, Surface; D004220:Disulfides; D018127:Tumor Necrosis Factor Receptor Superfamily, Member 7; D013755:Tetradecanoylphorbol Acetate