title: Idiotypic analysis of anti-I-Ak monoclonal antibodies. I. Production and characterization of syngeneic anti-idiotypic mAb against an anti-I-Ak mAb.
abstract: To analyze the idiotype (Id) of anti-Ia antibodies elicited during alloimmune responses, we produced syngeneic mouse anti-Id monoclonal antibodies (mAb) reactive with the Id of the 11-5.2.1.9 (11-5) mouse anti-I-Ak (BALB/c anti-CKB) mAb. Two such anti-Id mAb, IA2 (IgG2a) and IIID1 (IgG1), detect structurally related idiotopes located within the binding site of 11-5 for I-Ak antigens. A third anti-Id mAb, VC6 (IgG1), detects an idiotope located either inside or outside of, but presumably proximal to, the 11-5 antigen-binding site, because its expression correlates with the antigenic specificity of 11-5. None of the idiotopes detectable by these three anti-Id mAb are accessible when the binding site of 11-5 is occupied by an I-Ak molecule. The association constants of these anti-Id mAb for their cognate Fab-linked Id range from 2 X 10(9) to 1 X 10(10) M-1. The three anti-Id-producing hybridomas were found with a frequency of 0.008% among growing hybrid colonies. Even though these anti-Id mAb detect public idiotopes (IdX) on 11-5, they do not detect the presence of such IdX markers in the sera of five syngeneic BALB/c mice hyperimmunized with C3H (I-Ak) spleen cells. This suggests that 11-5 represents a BALB/c idiotype infrequently expressed by serum immunoglobulins. The 11-5 idiotopes detectable by IA2, IIID1, and VC6 seem to be conformationally determined by the interaction of 11-5 H and L chains and are not confined to one or the other of these subunit polypeptides. Thus, the expression of the 11-5 Id may be regulated by both VH and VL genes.
mesh_terms: D000818:Animals; D000888:Antibodies, Anti-Idiotypic / Q000096:biosynthesis*; D000911:Antibodies, Monoclonal / Q000032:analysis* / Q000096:biosynthesis / Q000276:immunology; D000915:Antibody Affinity; D000918:Antibody Specificity; D001666:Binding Sites, Antibody; D000949:Histocompatibility Antigens Class II / Q000276:immunology*; D006825:Hybridomas / Q000378:metabolism; D007106:Immune Sera / Q000032:analysis; D007143:Immunoglobulin Heavy Chains / Q000096:biosynthesis; D007130:Immunoglobulin Idiotypes / Q000235:genetics / Q000276:immunology / Q000302:isolation & purification*; D007147:Immunoglobulin Light Chains / Q000096:biosynthesis; D008214:Lymphocytes / Q000378:metabolism; D051379:Mice; D008805:Mice, Inbred A; D008807:Mice, Inbred BALB C; D013154:Spleen / Q000166:cytology
chemical_list: D000888:Antibodies, Anti-Idiotypic; D000911:Antibodies, Monoclonal; D000949:Histocompatibility Antigens Class II; D007106:Immune Sera; D007143:Immunoglobulin Heavy Chains; D007130:Immunoglobulin Idiotypes; D007147:Immunoglobulin Light Chains