Genome Sequence of Salmonella enterica Serovar Typhi Oral Vaccine Strain Ty21a

Construction, genotypic and phenotypic characterization, and immunogenicity of attenuated DeltaguaBA Salmonella enterica serovar Typhi strain CVD 915.

A promising live attenuated typhoid vaccine candidate strain for mucosal immunization was developed by introducing a deletion in the guaBA locus of pathogenic Salmonella enterica serovar Typhi strain Ty2. The resultant DeltaguaBA mutant, serovar Typhi CVD 915, has a gene encoding resistance to arsenite replacing the deleted sequence within guaBA, thereby providing a marker to readily identify t...

Salmonella enterica serovar Typhi Ty21a expressing human papillomavirus type 16 L1 as a potential live vaccine against cervical cancer and typhoid fever.

Human papillomavirus (HPV) vaccines based on L1 virus-like particles (VLPs) can prevent HPV-induced genital neoplasias, the precursors of cervical cancer. However, most cervical cancers occur in developing countries, where the implementation of expensive vaccines requiring multiple injections will be difficult. A live Salmonella-based vaccine could be a lower-cost alternative. We previously dem...

Immunization of Volunteers with Salmonella enterica Serovar Typhi Strain Ty21a Elicits the Oligoclonal Expansion of CD8 T Cells with Predominant V Repertoires

Characterization of CD8(+) effector T cell responses in volunteers immunized with Salmonella enterica serovar Typhi strain Ty21a typhoid vaccine.

Salmonella enterica serovar Typhi (S. typhi) strain Ty21a remains the only licensed attenuated typhoid vaccine. Despite years of research, the identity of the protective immunological mechanisms elicited by immunization with the Ty21a typhoid vaccine remains elusive. The present study was designed to characterize effector T cell responses in volunteers immunized with S. typhi strain Ty21a typho...

Live oral typhoid vaccine Ty21a induces cross-reactive humoral immune responses against Salmonella enterica serovar Paratyphi A and S. Paratyphi B in humans.

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 w...