Experiments with a model of aerosol immunization of mice and swine against Erysipelothrix insidiosa (E. i.).

Whole antigens as well as antigen fractions from E.i. were tested as aerosol vaccines. The aerosol produced by a jet nebulizer (Pari, Standard 088) with a capacity of 15 1 air per min and about 10g vaccine per hour was tested by size measuring of the aerosol particles and bacteriological evidence of E.i. in lung tissue. The main concern of the studies was to test the immunogenicity for laboratory animals which were exposed to the vaccines in a modified Henderson apparatus or in boxes of 30 1 respectively. Vaccination trials with conventional mice and piglets did not produce 100% protection against challenge infection by aerosol or subcutaneous route. Experiments with gnotobiotic piglets resulted in sufficient immunity against aerosol challenge with 100 LD50 when aerosols with living avirulent bacteria (strain B 10) were applied three times for one hour or once during three hours. A commercial vaccine from lyzed bacteria immunized only when aerosols were applied three times for three hours. For further immunological evaluation the sera of piglets were tested by means of an indirect fluorescent technique and by other serological methods.