Antibody reactions after aerogenous or subcutaneous immunization of pigs with Pasteurella multocida antigens

Depending upon the antigens used and the initial titres, subcutaneous immun ization of weaner pigs by means of a temperature-sensitive mutant of live P asteurella multocida (serovar A), resulted in a significant rise of the lev el of specific Ige antibody already present in blood serum, but not in lung lavage fluid, and a specific stimulation of lung clearance as compared to non-immunized controls. Aerogenous immunization of a total of 108 animals i n 18 experiments did not influence serum antibody titres but produced a sig nificant rise in lung antibodies and P. multocida clearance as compared to an identical number of controls. In all 12 immunization experiments using t he live mutant, increased specific IgA antibodies and in seven out of 10 ex periments, elevated IgG antibodies were measured. Only aerogenous immunizat ion was found to be capable of reducing the severity of pneumonia induced b y intrabronchial infection. (C) 2000 Elsevier Science Ltd. All rights reser ved.