title: Pneumococcal surface adhesin A (PsaA): a review.
abstract: Pneumococcal surface adhesin A (PsaA) is a surface-exposed common 37-kilodalton multi-functional lipoprotein detected on all known serotypes of Streptococcus pneumoniae. This lipoprotein belongs to the ABC-type transport protein complex that transports Mn(2+); it is also an adhesin that plays a major role in pneumococcal attachment to the host cell and virulence. PsaA is immunogenic and natural nasopharyngeal colonization of pneumococci elicits an increase in antibody towards PsaA. Hence, PsaA is being actively evaluated as a component of a vaccine in formulations composed of pneumococcal common proteins. PsaA has been expressed as an E. coli recombinant protein, purified, and evaluated in a phase one clinical trial. This article reviews PsaA, its structure and role in pneumococcal virulence, immunogenicity, and potential to reduce nasopharyngeal colonization (a major prerequisite for pneumococcal pathogenesis) as a component of a common pneumococcal protein vaccine.
authors.affiliation: Division of Bacterial Diseases, Centers for Disease Control and Prevention, Atlanta, Georgia 30333, USA.
authors.forename: Gowrisankar
authors.initials: G
authors.lastname: Rajam
authors.forename: Julie M
authors.initials: JM
authors.lastname: Anderton
authors.forename: George M
authors.initials: GM
authors.lastname: Carlone
authors.forename: Jacquelyn S
authors.initials: JS
authors.lastname: Sampson
authors.forename: Edwin W
authors.initials: EW
authors.lastname: Ades