Immune response to a secondary stimulus with Leptospira canicola and infectious canine hepatitis in beagles exposed to Sr90. LF-29.

The secondary immune response to L. canicola and ICH virus was 90 depressed in Beagle dogs which had inhaled particles of Sr 1-2 days and 7 days before the immune stimulus. The initial body burden was 31-46 microcuries per kilogram. The peak titre was reached for both antigens within eleven days in both control and exposed dogs. This amount of exposure did not accelerate the rate of decline of the antibodies, and the animals appeared to have recovered their abilityto produce antibodies after five months.