Hyperimmunization of rabbits with in vitro-grown Encephalitozoon cuniculi organisms

Specific hyperimmune anti-Encephalitozzon cuniculi antisera were produced i n immunocompetent rabbits. The animals were three times inoculated with cel l culture-grown microsporidan spores. A-group rabbits were immunized intrap eritoneally and B-group rabbits intravenously with gradually decreasing dos es of the agent spores at 16-day intervals. All rabbits receiving E. cunicu li developed serum antibodies, within 4 to 12 days, with IFA IgG titres of at least 1:64. Positive titres continued to day 48. After the third inocula tion, antibody levels rapidly increased and reached titres of 1: 1.024 up t o 1:8.192. The dynamics of specific antibody production consisted of three stages in both infected rabbit groups. The titres progresively increased an d first culminated on day 16 after the initial antigen doses. Descent of ti tres and dysbalance followed after the second inoculation, but the titres n ever dropped under values of 1:128. Post-third-injectional increase of IFA titres continued to day 44 when it culminated. The presence of high IFA IgG titres in hyperimmunized rabbits indicates tha t both routes of inoculation as well as the doses used for in vitro-grown E . cuniculi spores as an antigen appear to be suitable for the preparation o f specific hyperimmune antisera with sufficiently high antibody levels.