FOWL ANTIBODY .4. ESTIMATION OF HAEMOLYTIC FOWL COMPLEMENT

Abstract

The degree of haemolysis (y) of SRC [sheep red cells] sensitized with horse haemolysin by fowl complement was measured. A linear relation was not found between log fy/ (1-y)] and log x, the log volume of fowl complement used. Absorption of fowl C in the cold with packed SRC did not always result in C'' free from lysins to SRC. Estimations on two C'' sera from which SRC lysins had been removed gave a straight line with an indicator system of SRC sensitized with "immune" fowl haemolysin. Linear relations over a wide range of C'' concentrations, were also obtained when the indicator system consisted of SRC sensitized with a combination of "immune" and naturally occurring antibodies. The range could be extended by the addition of a small amount of heated normal fowl serum.