Cloning and expression of a @entity6586 sanguis surface antigen that interacts with a XXXX @entity25206 .

@entity1 @entity6586 @entity885 @entity25206 @entity460 @entity3282 @entity1098
@entity1 saliva contains a high-molecular-weight glycoprotein (agglutinin) which binds to specific streptococci in a @entity460 -dependent reaction leading to the formation of bacterial aggregates. We report the cloning of a gene encoding a surface antigen from @entity885 M5 and show that the expressed protein inhibits agglutinin-mediated aggregation and specifically binds the @entity25206 in a @entity460 -dependent fashion. Clones isolated from the immunological screening of @entity885 M5 genomic libraries with polyclonal antibodies against whole cells were assayed for the ability to compete with @entity885 for agglutinin. One clone, pSSP-5, expressed antigens of 165 and 130 kilodaltons (kDa) possessing this activity. A 3-kilobase-pair (kbp) insert fragment from this clone was used to screen a genomic library in lambda EMBL3 which resulted in the isolation of clone SSP-5A. This clone contained an insert of 17 kb and expressed proteins of 170 to 205 kDa that reacted with the anti-S. sanguis antibodies. Subcloning of a 5.3-kbp EcoRI-BamHI fragment from SSP-5A produced pEB-5, which expressed streptococcal components that were indistinguishable from SSP-5A. The streptococcal antigen was purified by gel permeation and ion exchange chromatography and shown to potently compete with @entity885 M5 cells for agglutinin. The antigen also bound purified @entity25206 in the presence of 1 mM @entity3282 . This binding was inhibited by @entity1098 . Both the SSP-5 antigen and a 205-kDa protein in surface protein extracts from @entity885 M5 cross-reacted with antibodies directed against antigen B from @entity6586 and SpaA from S. sobrinus 6715. These results indicate that a 205-kDa surface protein that is antigenically related to SpaA and antigen B is involved in the binding of @entity25206 to @entity885 M5.
