Epitope-specific binding of CD8 regulates activation of T cells and induction of cytotoxicity.
Functions of the CD8 molecule were examined to determine whether CD8 is merely a ligand-binding molecule and/or is involved in signal transduction. Using KT112 (anti-CD8 beta), CD8 was demonstrated to transduce an activation signal leading to cytotoxicity. Conformational changes of the CD8 molecule might be responsible for the activation, because (i) KT15 (anti-monomorphic CD8 alpha), but not antibodies specific for polymorphic CD8 alpha determinants, abrogated KT112 (anti-CD8 beta)-induced cytotoxicity without blocking the binding of KT112, whilst (ii) KT112 (anti-CD8 beta) inhibited KT15 (anti-monomorphic CD8 alpha)-mediated augmentation of proliferation triggered by a V beta 11-specific antibody without blocking the binding of KT15.
Tomonari
K
K
Transplantation Biology Section, MRC Clinical Research Centre, Harrow, UK.
Spencer
S
S
D000818:Animals; D000911:Antibodies, Monoclonal / Q000276:immunology; D015703:Antigens, CD / Q000502:physiology*; D000945:Antigens, Differentiation, T-Lymphocyte / Q000276:immunology / Q000502:physiology*; D017252:CD3 Complex; D016827:CD8 Antigens; D003602:Cytotoxicity, Immunologic; D000939:Epitopes; D008213:Lymphocyte Activation; D051379:Mice; D011233:Precipitin Tests; D051381:Rats; D011948:Receptors, Antigen, T-Cell / Q000276:immunology; D013601:T-Lymphocytes / Q000276:immunology*
D000911:Antibodies, Monoclonal; D015703:Antigens, CD; D000945:Antigens, Differentiation, T-Lymphocyte; D017252:CD3 Complex; D016827:CD8 Antigens; D000939:Epitopes; D011948:Receptors, Antigen, T-Cell