Hyperimmunization of rabbits with in vitro-grown Encephalitozoon cuniculi organisms

Specific hyperimmune anti-Encephalitozzon cuniculi antisera were produced in immunocompetent rabbits. The animals were three times inoculated with cell culture-grown microsporidan spores. A-group rabbits were immunized intraperitoneally and B-group rabbits intravenously with gradually decreasing doses of the agent spores at 16-day intervals. All rabbits receiving E. cuniculi 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 inoculation, antibody levels rapidly increased and reached titres of 1: 1.024 up to 1:8.192. The dynamics of specific antibody production consisted of three stages in both infected rabbit groups. The titres progresively increased and first culminated on day 16 after the initial antigen doses. Descent of titres and dysbalance followed after the second inoculation, but the titres never 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 that 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 of specific hyperimmune antisera with sufficiently high antibody levels.