Vaccines against Bacterial Enteric Infections

• Enteric infections by primarily Shigella, Salmonella typhi, enterotoxigenic Escherichia coli (ETEC), and Vibrio cholerae cause up to 1 billion disease episodes and 1 million deaths annually. Potentially, all of these pathogens could be controlled by the effective use of vaccines, yet vaccines are currently available only against S. typhi and V. cholerae. Although it is important to develop effective vaccines for the remaining primary pathogens also, this should not detract from the urgency to use the available life-saving and cost-effective vaccines against typhoid and cholera more broadly in public health programs in high-endemicity countries. Enteric pathogens differ in the way they cause infection and disease; this in turn has implications for the design of vaccines. For V. cholerae and ETEC, which colonize but do not invade the intestinal mucosa and elicit diarrhea through secreted enterotoxins, immune protection is attributed almost exclusively to intestinal secretory immunoglobulin A (SIgA) antibodies inhibiting colonization and/or toxin action; consistent with this, licensed cholera vaccines and the leading ETEC vaccine candidates currently in clinical testing are administered orally and based on killed or live-attenuated vaccines inducing intestinal antibacterial ± antitoxic SIgA immunity (and mucosal IgA memory). Protective immunity against invasive enteropathogens, on the other hand, can be conferred by both intestinal SIgA and systemic IgG antibodies; consequently, both oral (live-attenuated) and injectable (Vi polysaccharide) vaccines are available against S. typhi, and likewise vaccine candidates against Shigella and other invasive enteropathogens such as Salmonella paratyphi and Campylobacter include both oral-mucosal and parenteral vaccines. Research on oral-mucosal adjuvants, novel antigen-delivery systems, and immunological correlates of protection could further accelerate the development of new or improved enteric vaccines. © 2015 Elsevier Inc. All rights reserved.

Ämnesord

MEDICIN OCH HÄLSOVETENSKAP  -- Medicinska och farmaceutiska grundvetenskaper -- Immunologi inom det medicinska området (hsv//swe)

MEDICAL AND HEALTH SCIENCES  -- Basic Medicine -- Immunology in the medical area (hsv//eng)

Nyckelord

Cholera

Enteric infections

Mucosal immunity

Oral vaccines

Shigella

Typhoid

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