Intestinal–mucosal IgA anti–LPS and serum vibriocidal antibody responses elicited by two rounds of oral immunizations in Balb/c mice two weeks apart with formalin–killed MS1568 and MS1580 whole cell vaccines as compared to Dukoral vaccines; immunizations and collection of tissue specimens are fully described in Materials and Methods.

<p>(A) IgA anti–LPS antibody levels in fecal extracts (expressed as units per mg of total IgA measured by ELISA); and (B) the same in small intestinal tissue extracts. (C) Serum vibriocidal antibody responses against Inaba test organisms; and (D) the same against Ogawa test organisms. Bars represent the pooled results (geometric mean values ± SEM) from two separate experiments in Balb/c mice, each with 8 animals per group. Analyses of data by ANOVA showed that post–immunization antibody levels did not differ significantly between any of the immunization groups.