This study for the first time characterizes OSP-specific serum, mucosal and memory B cell responses in adults vaccinated with two doses of an oral cholera vaccine, Shanchol, in Bangladesh where it has been shown that OSP-specific serum and mucosal immune responses, as well as IgA memory B cell responses are maximal following the first dose of vaccination, without evident boosting with the second dose. The gene discussed is CLDN11; the disease is vibrio infectious disease.