Comparative Immunologic Activities of Polyclonal Antibodies Induced by Variably-Constituted Vibrio cholerae Ol (El Tor, Ogawa) Whole Cell Antigens

Abstract

Three types of Vibrio cholerae (El tor, Ogawa) whole cell antigens constituted with liquid paraffin adjuvant (LPA), Freund’s incomplete adjuvant (FIA) and physiological saline (SA) were used for polyclonal antisera production in adult rabbits. Antisera were compared for serologic reactivities with homologous and heterologous whole cell antigens. Antisera were compared for non-specific agglutination with non-vibrio organisms and vibriocidal antibody titres against homologous Vibrio cholerae whole cell suspension in saline. The LPA and SA antisera showed cross-reactivities with Escherichia coli at titres of 20 and < 10 respectively. Agglutination titres of LPA and FIA antisera against V. cholerae were 1280 each, while the titre of SA antiserum was 640. LPA and FIA antisera had vibriocidal titres of > 1280, while the titre of SA antiserum was 320. When cross reactive LPA and SA antisera were absorbed with E. coli, reactivity titres with homologous antigens were 640 each for LPA and SA. FIA had superior immunogenicity compared with LPA and SA, and agglutinins by FIA were more specific. Liquid paraffin appears to be a suitable low cost adjuvant for raising high quality antisera in rabbits. However, precautions should be taken to improve specificity by absorbing cross-reacting antibodies.