Impact of human anti-O-specific polysaccharide (OSP) antibody on Vibrio cholerae O1 in complex media containing mucin

Antibodies targeting the O-specific polysaccharide (OSP) of Vibrio cholerae O1 are a main determinant of protection against cholera. These antibodies can agglutinate bacteria, and can also directly inhibit V. cholerae motility, including at sub-agglutinating conditions. In order to evaluate for possible additional impacts of OSP-specific antibody on V. cholerae, we assessed the transcriptional profile of V. cholerae exposed to an anti-OSP human monoclonal antibody (G1), including in the presence of mucin, the principal component of intestinal mucous. We identified a subset of genes whose expression was significantly altered in the presence of anti-OSP antibody and mucin, including those involved in V. cholerae metabolism, transport, stress response, biofilm formation, motility, and secondary messenger signaling. Our results suggest a broad impact of anti-OSP antibodies on V. cholerae in the presence of mucin and identify several possible mechanisms by which anti-OSP antibodies might protect against cholera. Overall design: Vibrio cholerae C6706 bacteria cultured under toxin-inducing conditions were diluted to a subagglutinating optical density (600 nm) of =0.1 and exposed to two concentrations (0.0125 µM and 0.125 µM) of human monoclonal immunoglobulin (Ig) G1 targeting V. cholerae O-specific polysaccharide component of LPS (clone G1 - CF21.2.G01) or anti-flagellin antibody as a control (clone B12 -AT11.1.B12) in either Luria Bertani (LB) broth or LB containing 1% w/v porcine stomach mucin (LBM).