Immunization with the conjugate vaccine Vi-CRM₁₉₇ against Salmonella typhi induces Vi-specific mucosal and systemic immune responses in mice.
Typhoid fever is a public health problem, especially among young children in developing countries. To address this need, a glycoconjugate vaccine Vi-CRM₁₉₇, composed of the polysaccharide antigen Vi covalently conjugated to the non-toxic mutant of diphtheria toxin CRM₁₉₇, is under development. Here, we assessed the antibody and cellular responses, both local and systemic, following subcutaneous injection of Vi-CRM₁₉₇. The glycoconjugate elicited Vi-specific serum IgG titers significantly higher than unconjugated Vi, with prevalence of IgG1 that persisted for at least 60 days after immunization. Vi-specific IgG, but not IgA, were present in intestinal washes. Lymphocytes proliferation after restimulation with Vi-CRM₁₉₇ was observed in spleen and mesenteric lymph nodes. These data confirm the immunogenicity of Vi-CRM₁₉₇ and demonstrate that the vaccine-specific antibody and cellular immune responses are present also in the intestinal tract, thus strengthening the suitability of Vi-CRM₁₉₇ as a promising candidate vaccine against Salmonella Typhi.
Laboratorio di Microbiologia Molecolare e Biotecnologia, Dipartimento di Biotecnologie, Università di Siena, Italy.
Fabio
F
Fiorino
Annalisa
A
Ciabattini
Simona
S
Rondini
Gianni
G
Pozzi
Laura B
LB
Martin
Donata
D
Medaglini
D000818:Animals; D000907:Antibodies, Bacterial / Q000097:blood; D000917:Antibody Formation; D001426:Bacterial Proteins / Q000276:immunology*; D049109:Cell Proliferation; D007111:Immunity, Cellular; D018928:Immunity, Mucosal; D007070:Immunoglobulin A / Q000276:immunology; D007074:Immunoglobulin G / Q000097:blood; D008198:Lymph Nodes / Q000276:immunology; D051379:Mice; D008807:Mice, Inbred BALB C; D011135:Polysaccharides, Bacterial / Q000276:immunology*; D012485:Salmonella typhi / Q000276:immunology; D013154:Spleen / Q000276:immunology; D013601:T-Lymphocytes / Q000276:immunology; D014435:Typhoid Fever / Q000517:prevention & control*; D014436:Typhoid-Paratyphoid Vaccines / Q000276:immunology*; D018074:Vaccines, Conjugate / Q000276:immunology
D000907:Antibodies, Bacterial; D001426:Bacterial Proteins; D007070:Immunoglobulin A; D007074:Immunoglobulin G; D011135:Polysaccharides, Bacterial; D014436:Typhoid-Paratyphoid Vaccines; D018074:Vaccines, Conjugate; C028581:CRM197 (non-toxic variant of diphtheria toxin)