The J558 VH CDR3 region contributes little to antibody avidity; however, it is the recognition element for cognate T cell control of the alpha(1-->3) dextran-specific antibody response.
Analysis of the humoral immune response of BALB/c mice to alpha(1-->3) dextran (Dex) reveals novel aspects of T cell-mediated control of 'type 2 thymus-independent' responses against polysaccharide antigens. The IgM and IgG antibody response, dominated by the J558 idiotype (Id), is controlled by Id-specific T cells. These regulatory T cells, for which the T cell clone 178-4 Ts with characterized TCR alpha and beta chain sequences is the prototype, expand in all BALB/c mice upon immunization with Dex. They suppress in a cognate interaction the expansion of J558 Id-bearing B cells, committed for production of IgG antibodies. Furthermore they provide a gate which precludes variability in the VH CDR3 region of IgG antibodies appearing occasionally in the periphery. The VH CDR3 region is the recognition element of 178-4 Ts analogous T cells but contributes little to affinity for the antigen. For recognition by 178-4 Ts cells not even minimal sequence deviations of the J558 Id peptide are allowed. The tight germline programmed complementarity between J558 Id-bearing Dex-specific B and J558 Id-specific 178-4 Ts analogous T cells leaves little room on both sides for ontogenetic variability.
Clemens
A
A
Institute for Immunology, University of Münster, Germany.
Rademaekers
A
A
Specht
C
C
Kölsch
E
E
D000595:Amino Acid Sequence; D000818:Animals; D000915:Antibody Affinity / Q000276:immunology*; D000918:Antibody Specificity / Q000276:immunology*; D001483:Base Sequence; D003911:Dextrans / Q000276:immunology* / Q000378:metabolism; D018984:Epitopes, T-Lymphocyte / Q000276:immunology; D007108:Immune Tolerance; D007074:Immunoglobulin G / Q000096:biosynthesis*; D007143:Immunoglobulin Heavy Chains / Q000276:immunology*; D007130:Immunoglobulin Idiotypes / Q000276:immunology; D007135:Immunoglobulin Variable Region / Q000276:immunology*; D008211:Lymphocyte Cooperation; D051379:Mice; D008807:Mice, Inbred BALB C; D008810:Mice, Inbred C57BL; D008819:Mice, Nude; D008969:Molecular Sequence Data; D013601:T-Lymphocytes / Q000166:cytology / Q000276:immunology*
D003911:Dextrans; D018984:Epitopes, T-Lymphocyte; D007074:Immunoglobulin G; D007143:Immunoglobulin Heavy Chains; D007130:Immunoglobulin Idiotypes; D007135:Immunoglobulin Variable Region; C040834:alpha-1,3-dextran