ArticleClinical and vaccine immunology : CVI2012
Live oral typhoid vaccine Ty21a induces cross-reactive humoral immune responses against Salmonella enterica serovar Paratyphi A and S. Paratyphi B in humans.
Article in Clinical and vaccine immunology : CVI, 2012. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 48 papers, 1 of them a synthesis that pooled it.
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The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.
The trial behind it
Trials whose registry record cites this paper, or whose number appears in the abstract. A trial that started after this paper was published is citing it as background, not reporting it.
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Who cites it
48 citing papers in PubMed, 1 synthesis or guideline pooled it, 79 citations in OpenAlex.
- Typhoid conjugate vaccines for preventing typhoid fever (enteric fever).The Cochrane database of systematic reviews · 2025Pooled it
- A combination typhoid and non-typhoidal Salmonella polysaccharide conjugate vaccine in healthy adults: a randomized, placebo-controlled phase 1 trial.Nature medicine · 2025Trial
- Homologous and heterologous re-challenge with Salmonella Typhi and Salmonella Paratyphi A in a randomised controlled human infection model.PLoS neglected tropical diseases · 2020Trial
- Trial
- Live oral Salmonella enterica serovar Typhi vaccines Ty21a and CVD 909 induce opsonophagocytic functional antibodies in humans that cross-react with S. Paratyphi A and S. Paratyphi B.Clinical and vaccine immunology : CVI · 2014Trial
- Research progress on immunoprotective mechanisms of enteric fever and vaccine development.Journal of advanced research · 2026Review
- Multivalent vaccines for invasiveInfection and immunity · 2026Review
- Antibiotic Alternatives and Next-Generation Therapeutics forAntibiotics (Basel, Switzerland) · 2025Review
- Typhoid & paratyphoid vaccine development in the laboratory: a review & in-country experience.The Indian journal of medical research · 2024Review
- Exploring the Antimicrobial Resistance Profile ofAntibiotics (Basel, Switzerland) · 2024Article
- Salmonellosis: An Overview of Epidemiology, Pathogenesis, and Innovative Approaches to Mitigate the Antimicrobial Resistant Infections.Antibiotics (Basel, Switzerland) · 2024Review
- Role of cellular effectors in the induction and maintenance of IgA responses leading to protective immunity against enteric bacterial pathogens.Frontiers in immunology · 2024Review
- Estimating typhoid incidence from community-based serosurveys: a multicohort study.The Lancet. Microbe · 2022Article
- Paratyphoid Fever A: Infection and Prevention.Frontiers in microbiology · 2022Review
- Controlled human infectious models, a path forward in uncovering immunological correlates of protection: Lessons from enteric fevers studies.Frontiers in microbiology · 2022Review
- Article
- Cell mediated immune responses elicited in volunteers following immunization with candidate live oral Salmonella enterica serovar Paratyphi A attenuated vaccine strain CVD 1902.Clinical immunology (Orlando, Fla.) · 2019Article
- Effect of the live oral attenuated typhoid vaccine, Ty21a, on systemic and terminal ileum mucosal CD4+ T memory responses in humans.International immunology · 2019Article
- Association betweenHuman vaccines & immunotherapeutics · 2019Article
- Improving Our Understanding ofmSphere · 2018Article
Corrections and comments
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Authors and funding
5 authors at 1 institution in 1 country.
Funding
Abstract
Enteric fever caused by Salmonella enterica serovar Paratyphi A infection has emerged as an important public health problem. Recognizing that in randomized controlled field trials oral immunization with attenuated S. enterica serovar Typhi live vaccine Ty21a conferred significant cross-protection against S. Paratyphi B but not S. Paratyphi A disease, we undertook a clinical study to ascertain whether humoral immune responses could explain the field trial results. Ty21a immunization of adult residents of Maryland elicited predominantly IgA antibody-secreting cells (ASC) that recognize S. Typhi lipopolysaccharide (LPS). Cross-reactivity to S. Paratyphi A LPS was significantly lower than that to S. Paratyphi B LPS. ASC producing IgG and IgA that bind LPS from each of these Salmonella serovars expressed CD27 and integrin α4β7 (gut homing), with a significant proportion coexpressing CD62L (secondary lymphoid tissue homing). No significant differences were observed in serum antibody against LPS of the different serovars. Levels of IgA B memory (B(M)) cells to S. Typhi LPS were significantly higher than those against S. Paratyphi A or B LPS, with no differences observed between S. Paratyphi A and B. The response of IgA B(M) to outer membrane proteins (OMP) from S. Typhi was significantly stronger than that to OMP of S. Paratyphi A but similar to that to OMP of S. Paratyphi B. The percentages of IgG or IgA B(M) responders to LPS or OMP from these Salmonella strains were similar. Whereas cross-reactive humoral immune responses to S. Paratyphi A or B antigens are demonstrable following Ty21a immunization, they cannot explain the efficacy data gleaned from controlled field trials.
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Registered trials
Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.