title: Alternation of low and high affinities of secreted and cell-bound antibodies during the anamnestic response of rabbits to Salmonella senftenberg microorganisms.
abstract: We have investigated at the cellular level the variations in affinities of secreted antibodies and of cell receptors during the anamnestic response of rabbits, by using an immunization schedule made up of administrations, over successive intervals of 40 days, of Salmonella senftenberg vaccine. Affinities of free and membrane-bound antibodies biosynthesized at a given time were measured by inhibition of haemolytic plaque-forming cells (PFC) and rosette-forming cells (RFC) with spleen, lymph node, and peripheral blood cells. The immunodominant monosaccharide, methyl-alpha-D-glucopyranoside (alpha-Me-Glc), was used as inhibitor, and the target cells were coated with the O-specific polysaccharide of the immunogenic microorganisms. We observed that the monosaccharide concentration causing a 50% inhibition (I50) alternated between low and high values in both PFC and RFC assays. Furthermore, when sheep erythrocytes were coated with polysaccharides from other strains of Salmonella bearing the determinants for serotypes 1 or 3 the percentage of cross-reactive PFC obtained exhibited a reverse oscillating pattern of variation. These results demonstrated that affinity of secreted antibodies or of antigen-receptors of cells, directed against different determinants of the antigenic polysaccharide, alternated between low and high values after each new vaccine administration. Possible mechanisms accounting for this phenomenon are discussed.
mesh_terms: D000818:Animals; D000915:Antibody Affinity; D000941:Antigens; D001428:Bacterial Vaccines / Q000008:administration & dosage; D001666:Binding Sites, Antibody; D004926:Escherichia coli; D005260:Female; D006241:Haptens; D006462:Hemolytic Plaque Technique; D007114:Immunization; D008214:Lymphocytes / Q000276:immunology; D008297:Male; D009005:Monosaccharides / Q000494:pharmacology; D011134:Polysaccharides / Q000008:administration & dosage; D011817:Rabbits; D012397:Rosette Formation; D012475:Salmonella / Q000276:immunology*
chemical_list: D000941:Antigens; D001428:Bacterial Vaccines; D006241:Haptens; D009005:Monosaccharides; D011134:Polysaccharides