Streptococcus pneumoniae surface-exposed glutamyl tRNA synthetase, a putative adhesin, is able to induce a partially protective immune response in mice.
Glutamyl tRNA synthetase (GtS) has been found to be among the Streptococcus pneumoniae cell wall-derived proteins that have age-dependent immunogenicity in children. Here, GtS was cloned, expressed, and purified and then was used to immunize 7-week-old BALB/c OlaHsd mice. Serum obtained from mice immunized with recombinant (r) GtS cross-reacted with a 55.9-kDa protein, identified as GtS, in the cell wall fraction derived from genetically and capsularly unrelated strains of S. pneumoniae. Surface localization of GtS was further confirmed using flow cytometry analysis. The rGtS and anti-rGtS antiserum significantly inhibited the adhesion of 3 pairs of encapsulated and unencapsulated strains of S. pneumoniae to A549 cells. Thirty-nine percent of rGtS-immunized mice survived a lethal bacterial challenge, whereas no control mice survived. These results suggest that GtS, an age-dependent S. pneumoniae antigen, is a surface-located adhesin that is capable of inducing a partially protective immune response against S. pneumoniae in mice.
Mizrachi Nebenzahl
Yaffa
Y
Pediatric Infectious Disease Unit, Soroka University Medical Center, Beer Sheva, Israel. ymizr@bgu.ac.il
Bernstein
Anka
A
Portnoi
Maxim
M
Shagan
Marilou
M
Rom
Slava
S
Porgador
Angel
A
Dagan
Ron
R
D000328:Adult; D000818:Animals; D000907:Antibodies, Bacterial / Q000097:blood; D001426:Bacterial Proteins / Q000276:immunology*; D002448:Cell Adhesion / Q000276:immunology; D002460:Cell Line; D002675:Child, Preschool; D003001:Cloning, Molecular; D005260:Female; D015870:Gene Expression; D005975:Glutamate-tRNA Ligase / Q000276:immunology*; D006801:Humans; D007223:Infant; D008565:Membrane Proteins / Q000276:immunology*; D051379:Mice; D008807:Mice, Inbred BALB C; D022242:Pneumococcal Vaccines / Q000276:immunology*; D011994:Recombinant Proteins / Q000096:biosynthesis / Q000276:immunology / Q000302:isolation & purification; D013290:Streptococcal Infections / Q000517:prevention & control*; D013296:Streptococcus pneumoniae / Q000201:enzymology / Q000276:immunology*; D016019:Survival Analysis; D022223:Vaccines, Subunit / Q000276:immunology
D000907:Antibodies, Bacterial; D001426:Bacterial Proteins; D008565:Membrane Proteins; D022242:Pneumococcal Vaccines; D011994:Recombinant Proteins; D022223:Vaccines, Subunit; D005975:Glutamate-tRNA Ligase