Comparison of Streptococcus mutans and streptococcus sanguis receptors for human salivary agglutinin

Donald R. Demuth, Margaret S. Lammey, Margaret Huck, Edward T. Lally, Daniel Malamud

    Research output: Contribution to journalArticlepeer-review


    Oral streptococci vary in their susceptibility to salivary agglutinin-mediated aggregation. To understand the molecular basis of this specificity, the structure and function of receptors for agglutinin from Streptococcus mutans KPSK2 (MSL-1) and Streptococcus sanguis M5 (SSP-5) were compared. Immunological screening of an S. mutans KPSK2 genomic DNA library yielded two identical clones expressing a streptococcal protein that co-migrated with a 220 kDa peptide in SDS extracts from this organism. This protein inhibited agglutinin-mediated aggregation of S. mutans KPSK2 in a dose-dependent manner. The MSL-1 gene is homologous to the S. Mutans SpaP and pac genes although single base substitutions alter several amino acids. MSL-1 is also similar to the agglutinin receptor (SSP-5) cloned from S. sanguis M5. All three proteins, MSL-1, P1, and SSP-5 share at least one epitope since monoclonal and polyclonal anti-SSP-5 antibodies react with both MSL-1 and P1. However, other monoclonal antibodies are specific for SSP-5 and appear to react with a peptide domain exhibiting little homology to MSL-1 or P1. Sugar inhibition studies showed that agglutinin-mediated aggregation of S. mutans KPSK2 was most potently inhibited by fucose and lactose. Sialic acid, a potent inhibitor of S. sanguis aggregation, had no effect on the interaction of agglutinin with S. mutans KPSK2. These results suggest that while the MSL-1 and SSP-5 proteins are genetically and immunologically related, their specificity for binding sites on agglutinin differs.

    Original languageEnglish (US)
    Pages (from-to)199-211
    Number of pages13
    JournalMicrobial Pathogenesis
    Issue number3
    StatePublished - Sep 1990


    • Streptococcus mutans
    • Streptococcus sanguis
    • receptor
    • salivary agglutinin

    ASJC Scopus subject areas

    • Microbiology
    • Infectious Diseases


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