Allergic Reactions in Rabbits to Bacterial Antigens.

Abstract

In January, 1927, Mackenzie and Hanger 1 described reactions in the human, following intradermal injections of antigens prepared from streptococci obtained from throats of rheumatic patients and normal individuals. These antigens were thermostable and non-neutralizable by immune serum. Like tuberculin, they gave a negative reaction during most acute infections, and in very young children. It was assumed by us that the chronic lesions, produced in the nasopharynx and tonsils of even normal individuals by the streptococcus, render such persons allergic to the bacterial protein as is manifested by these skin reactions. When these same streptococcus antigens, strongly active for the human, are injected into the skin of normal rabbits, the animals seldom show a local response. Cultures were therefore made of the naso-pharynx of rabbits to determine the presence or absencee of the streptococcus, and also to establish the general character of the bacterial flora in these animals.

Our results agree essentially with those of Webster 2 and of Bull, 3 who note the overwhelming predominance of gram negative organisms, among which, members of the B. lepisepticum group are almost a constant finding. Webster has shown 4 that this group is responsible for snuffles and most of the other chronic respiratory infections in the rabbit. It seems reasonable to assume that in this animal the rôle played by B. lepisepticum is quite analogous to that of the streptococcus in man, and that the rabbit should show allergic reactions to antigens prepared from these organisms. Antigens were prepared from a number of strains of B. lepisepticum and B. bronchisepticus, isolated from the naso-pharynx of rabbits in our laboratory, among which sporadic cases of snuffles had appeared.