Phagocytic activity of two lines of chickens divergently selected for antibody production

Differences in phagocytic capacity of two chicken lines selected for high (H) or low (L) antibody response against sheep red blood cells (SRBC) were studied in 8 month old cocks of the seventh selection generation. The H line cocks had significantly higher agglutinin titers after immunization with SRBC than the L line. The total clearance capacity of the phagocytes, measured by the clearance of carbon particles from the blood, did not differ between the lines. The L line cocks had more circulating granulocytes. However, the granulocytes of the H line phagocytized more yeast cells than those of the L line. Neither in immunized nor in non-immunized cocks, were line differences found in the intracellular destruction of antigen by phagocytes, estimated as the superoxide production during phagocytosis and the plasma levels of lysozyme activity and acid phosphatase, before and after immunization. It was concluded that the line difference in antibody response was not due to measurable differences in phagocytic activity.