Selective breeding of high and Low antibody-responder lines of guinea pigs

High (H) and Low (L) antibody-responder lines of guinea pigs were produced by selective breeding for the character quantitative agglutinin responsiveness to optimal doses of sheep erythrocytes (SE) and chicken erythrocytes (CE). The non cross-reacting SE and CE were alternated with each generation in order to avoid the specific interference of maternally transmitted antibodies. The continuous distribution of the phenotypes in the foundation population (F₀) and the progressive interline divergence during eight consecutive generations of selective breeding demonstrates that the character investigated is submitted to polygenic regulation. The difference in the peak agglutinin titers between the H and L lines of the eighth generation (HF₈/LF₈) is eight fold. The mean heritability (h²) of the character investigated, measured from the interline divergence of the eight generations of selection is 0.18±0.04. The h² value was established by the linear regression of the cumulated response to selection (R) on the cumulated selection differential (S). The selective breeding has a nonspecific effect because it also modifies the antibody responsiveness to other immunogens, such as f and s antigens ofSalmonella typhimurium or human erythrocytes, that are immunologically unrelated to those used in the selection.