T cell-B cell interaction: autoreactive T cells recognize B cells through a terminal mannose-containing superantigen-like glycoprotein.
Rat autoreactive T cells (ATs) recognize a membrane component(s) on syngeneic B cells in association with class II MHC antigens resulting in proliferation of ATs as well activation and differentiation of B cells. Results presented herein indicate that ATs recognize a stimulating antigen(s) SA, in association with class II MHC antigens, on the B cell surface. Our studies using inhibitors of carbohydrate and protein synthesis suggest that SA is a glycoprotein(s) with a high turnover rate but is not an immunoglobulin. Treatment of B cells with mannosidase abrogates their ability to stimulate AT proliferation. Furthermore, pretreatment of B cells with GNA (a lectin from Galanthus nivalis that reacts with free terminal-mannose residues on glycoconjugates) also inhibits their ability to stimulate ATs. However, these treatments do not affect the competence of B cells to stimulate an allogeneic MLR or present a conventional antigen to T cells. The frequency of CD4+ T cells proliferating in response to syngeneic B cells is very high (0.2-0.5%) and is in line with frequencies seen in "superantigen"-type responses. Moreover, T cell receptors expressed on ATs use mainly V beta 6, V beta 11, and V beta 8 regions. Based on these data, SA appears to be a fast turnover, terminal mannose-containing, superantigen-like glycoprotein on the B cell surface.
Savage
S M
SM
Immunotoxicology Division, Lovelace Medical Foundation, Albuquerque, New Mexico 87108.
Donaldson
L A
LA
Sopori
M L
ML
D000818:Animals; D001324:Autoantigens / Q000737:chemistry / Q000276:immunology*; D001402:B-Lymphocytes / Q000187:drug effects / Q000276:immunology*; D027801:Galanthus; D006023:Glycoproteins / Q000737:chemistry / Q000276:immunology*; D008213:Lymphocyte Activation / Q000187:drug effects / Q000276:immunology; D008358:Mannose / Q000032:analysis* / Q000276:immunology; D008361:Mannosidases / Q000494:pharmacology; D051381:Rats; D011912:Rats, Inbred ACI; D011916:Rats, Inbred F344; D013601:T-Lymphocytes / Q000276:immunology*
D001324:Autoantigens; D006023:Glycoproteins; D008361:Mannosidases; D008358:Mannose