Assessment of antibody responses and protective immunity in cholera vaccinated subjects

Abstract

Cross-reactive antibody responses were assessed in volunteers vaccinated with classical Inaba and Ogawa cholera vaccines. The El Tor, Ogawa vibrios, the most frequent biotype and serotype found to be the causative agent of cholera in Thailand, or their product were used throughout the in vitro and in vivo tests. The tests involved were the passive hemagglutination test, vibriocidal test and the mouse protection test. Classes of specific immunoglobulins produced in the volunteers were determined using anti-immunoglobulin enhancement of hemagglutination. It was found that the levels of hemagglutinating and vibriocidal antibodies reached their peak on day 7 after the vaccination and were statistically constant for 3 months. A significant decrease was observed thereafter. The mouse protective antibody titer was highest a 1 month after the vaccination then declined significantly at the 6th month. Classes of specific immunoglobulins were found to be either IgM or IgG alone or a mixture of both.