DIVERGENT ANTIBODY-RESPONSES TO VACCINES AND DIVERGENT BODY WEIGHTS OF CHICKEN LINES SELECTED FOR HIGH AND LOW HUMORAL RESPONSIVENESS TO SHEEP RED-BLOOD-CELLS

Primary and secondary antibody responses to intramuscularly administer ed proteins of Eschericia coli (F11), Newcastle disease virus (NCD), i nfectious bronchitis virus (IB), and infectious bursal disease virus ( IBD), respectively, were measured at weekly intervals in two chicken l ines. The latter had been divergently selected for high and low antibo dy responses to sheep red blood cells (SRBC), and in a random-bred con trol line. An oil-based adjuvant was required to induce primary and se condary antibody responses to NCD, IB, and IBD. With respect to F11, e levated antibody responses were found in birds sensitized and boosted to F11 with and without adjuvant. The humoral response to F11 and to a ll viral antigens was significantly higher in the high (H) line than i n the low (L) line, whereas the control (C) line showed intermediate t iters. At 5 and 17 weeks of age, L line birds were significantly heavi er than birds of che H and the C lines. A negative phenotypic correlat ion within lines between body weight at 17 weeks of age and antibody t iters at 1 week after sensitization was found, but no further correlat ions between humoral responses and body weight or growth could be esta blished. The present results suggest that selection for enhanced humor al responsiveness to SRBC resulted in enhanced responsiveness to compo nents of several vaccines. Mechanisms underlying the relationship betw een divergent selection for immune responsiveness and body weight are discussed.