Salivary agglutinin, which binds Streptococcus mutans and Helicobacter pylori, is the lung scavenger receptor cysteine-rich protein gp-340.

• Salivary agglutinin is a high molecular mass component of human saliva that binds Streptococcus mutans, an oral bacterium implicated in dental caries. To study its protein sequence, we isolated the agglutinin from human parotid saliva. After trypsin digestion, a portion was analyzed by matrix-assisted laser/desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS), which gave the molecular mass of 14 unique peptides. The remainder of the digest was subjected to high performance liquid chromatography, and the separated peptides were analyzed by MALDI-TOF/post-source decay; the spectra gave the sequences of five peptides. The molecular mass and peptide sequence information showed that salivary agglutinin peptides were identical to sequences in lung (lavage) gp-340, a member of the scavenger receptor cysteine-rich protein family. Immunoblotting with antibodies that specifically recognized either lung gp-340 or the agglutinin confirmed that the salivary agglutinin was gp-340. Immunoblotting with an antibody specific to the sialyl Le(x) carbohydrate epitope detected expression on the salivary but not the lung glycoprotein, possible evidence of different glycoforms. The salivary agglutinin also interacted with Helicobacter pylori, implicated in gastritis and peptic ulcer disease, Streptococcus agalactiae, implicated in neonatal meningitis, and several oral commensal streptococci. These results identify the salivary agglutinin as gp-340 and suggest it binds bacteria that are important determinants of either the oral ecology or systemic diseases.

Ämnesord

MEDICIN OCH HÄLSOVETENSKAP  -- Annan medicin och hälsovetenskap (hsv//swe)

MEDICAL AND HEALTH SCIENCES  -- Other Medical and Health Sciences (hsv//eng)

Nyckelord

Agglutinins

chemistry

metabolism

Amino Acid Sequence

Bacterial Adhesion

Blotting

Western

Helicobacter pylori

metabolism

Humans

Lung

metabolism

microbiology

Molecular Sequence Data

Peptide Mapping

Protein Binding

Receptors

Immunologic

metabolism

Saliva

metabolism

Spectrometry

Mass

Matrix-Assisted Laser Desorption-Ionization

Streptococcus mutans

metabolism

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