Parenteral Vaccination with a Cholera Conjugate Vaccine Boosts Vibriocidal and Anti-OSP Responses in Mice Previously Immunized with an Oral Cholera Vaccine.

Aklima Akter,Stephen B Calderwood,Jason B Harris,Richelle C Charles,Taufiqur R Bhuiyan,Rajib Biswas,Peng Xu,Firdausi Qadri,Pavol Kováč,Meagan Kelly,Edward T Ryan

doi:10.4269/ajtmh.20-1511

Abstract

.Oral cholera vaccination protects against cholera; however, responses in young children are low and of short duration. The best current correlates of protection against cholera target Vibrio cholerae O-specific polysaccharide (anti-OSP), including vibriocidal responses. A cholera conjugate vaccine has been developed that induces anti-OSP immune responses, including memory B-cell responses. To address whether cholera conjugate vaccine would boost immune responses following oral cholera vaccination, we immunized mice with oral cholera vaccine Inaba CVD 103-HgR or buffer only (placebo) on day 0, followed by parenteral boosting immunizations on days 14, 42, and 70 with cholera conjugate vaccine Inaba OSP: recombinant tetanus toxoid heavy chain fragment or phosphate buffered saline (PBS)/placebo. Compared with responses in mice immunized with oral vaccine alone or intramuscular cholera conjugate vaccine alone, mice receiving combination vaccination developed significantly higher vibriocidal, IgM OSP-specific serum responses and OSP-specific IgM memory B-cell responses. A combined vaccination approach, which includes oral cholera vaccination followed by parenteral cholera conjugate vaccine boosting, results in increased immune responses that have been associated with protection against cholera. These results suggest that such an approach should be evaluated in humans.

Highlights

MATERIALS AND METHODSCholera is a severe dehydrating diarrheal disease caused by the Gram-negative, motile, bacterium Vibrio cholerae.[1]
We were interested in understanding whether a combination vaccine approach of oral cholera vaccine priming followed by parenteral cholera conjugate vaccine boosting would increase O-specific polysaccharide (OSP)-specific, vibriocidal, and memory responses compared with immunization with oral cholera vaccination alone or parenteral cholera vaccination alone
We demonstrated that priming with an oral cholera vaccine followed by parenteral boosting with an OSP cholera conjugate vaccine can increase vibriocidal responses, AKTER, KELLY, AND OTHERS

Summary

Introduction

MATERIALS AND METHODSCholera is a severe dehydrating diarrheal disease caused by the Gram-negative, motile, bacterium Vibrio cholerae.[1]. Oral vaccination alone did not induce IgG (Figure 3A) or IgA (Supplemental Figure 1) OSP-specific responses; there was a low level IgM response, but this was not statistically significant (Figure 3B).

Results

Conclusion