Genetic controls of T cell-independent Thy-1 alloantibody responses

Antibody response to haptenic sugar antigen: immunodominancy of protein-bound lactose formed by amino-carbonyl reaction

Several reducing sugars with structural analogy (glucose, galactose, lactose, melibiose, maltose and cellobiose) were bound to a carrier protein ovalbumin by amino-carbonyl reaction, and the non-enzymatically glycosylated proteins were injected into mice (BALB/c, C57BL/6, DBA/2 and C3H/He strains) with Freund's adjuvant. Antibody responses to the haptenic sugar antigens were analyzed quantitatively by enzyme-linked immunosorbent-assay using each sugar-bovine serum albumin complex. The haptenic sugar antigen from lactose induced a markedly higher response of specific antibody as compared with the haptenic sugar antigens from the other sugars. The antibody raised against the lactose adduct reacted well with lactulose (4-o-beta-D-galactopyranosyl-D-fructose) or alpha-N-acetyl-epsilon-N-deoxylactulosyl-L-lysine. The results suggested that immunogenicity of haptenic sugar antigens was remarkably different in sugar chemical structure, and that the lactose adduct formed by lactose-protein amino-carbonyl reaction could be an immunodominant antigenic determinant.

Autoimmunity to Thy-1

Conditions are described for the induction of autoimmunity to Thy-1 and a large panel of monoclonal CBA and AKR autoantibodies has been characterized. These reveal a hitherto unrecognized complexity at the Thy-1 locus and evidence for intragenic control. Epitopes recognized by the autoantibodies differed in species and tissue distribution from alloantigenic determinants but their specificity was confirmed by transfection studies with the cloned Thy-1b gene. The quantitative and qualitative differences in epitope expression between Thy-1a and Thy-1b alleles were inherited as single Mendelian traits and in the absence of recombinants, suggesting translational control.