Introduction: Previous studies have shown 37.8 kDa pili subunit protein of Vibrio cholerae and 49.8 kDa pili subunit protein of Shigella flexneri can act as an adhesion molecule to initiate infection. These molecules also have the ability to agglutinate blood. The present study assessed mucosal and systemic immunity following vaccination using 37.8 kDa V. cholerae and protection against S. flexneri.
Subjects and methods: Haemagglutination test was performed after purification of V. cholerae protein, followed by an anti-haemagglutination test. The intestinal weight and colony count were used to validate the protective effect on balb/c mice which were divided into the naive group, Shigella-positive control group, Vibrio-positive control group, V. cholerae infected-Vibrio-vaccinated group and S. flexneri-infected-Vibrio-vaccinated group. Th17, Treg, interleukin (IL) IL-17A, β-defensin and secretory-immunoglobulin A (s-IgA) were also measured to determine the systemic and mucosal immunity after vaccination.
Results: The haemagglutination and anti-haemagglutination tests showed that the 37.8 kDa protein could inhibit 49.8 kDa of the S. flexneri pili subunit. Decreased intestinal weight and colony count of vaccinated group compared to naive group also support cross reaction findings. Vaccination also generates higher level of Th17, Treg, IL-17A, β-defensin and s-IgA significantly.
Conclusions: 37.8 kDa subunit pili can act as a homologous vaccine candidate to prevent V. cholerae and S. flexneri infection.
Keywords: 37.8 kDa Vibrio cholerae; 49.8 kDa Shigella flexneri; adhesion molecule; vaccine.