Bovine caseinate, derivatives of its glycosylated moiety [caseinoglycomacropeptide (CGP)], and caseinophosphopeptides were evaluated as inhibitors of adhesion of oral bacteria to saliva-coated hydroxyapatite beads (S-HA). All milk casein-derived components behaved as potent inhibitors of Streptococcus sanguis OMZ 9 and Streptococcus sobrinus OMZ 176 adhesion to S-HA, whereas neither bovine serum albumin nor polyethyleneglycol were able to interfere with the adhesion of these strains. By contrast, none of the molecular species tested was able to inhibit the attachment of Actinomyces viscosus Ny 1 to S-HA. On the other hand, casein derivatives were shown to displace human serum albumin from S-HA beads. They were also able to bind to the bacterial cell surface of all strains examined. Collectively, these findings suggest that interactions between acidic casein-derived milk components and the biological surfaces involved in bacterial adhesion to S-HA result in an inhibitory effect that is selective for the oral streptococci examined.

The role of cell surface glycoconjugates as possible adhesion receptors for Candida albicans yeasts on human buccal epithelial cells was investigated by using a quantitative radiometric assay involving 14C-metabolically labeled microorganisms. Various structurally defined soluble glycopeptides and oligosaccharides were tested at a low concentration (1 mg/ml) for their ability to competitively inhibit yeast adhesion to such exfoliated cells. Comparisons were also made with various molecular species previously proposed to act as adhesion molecules. A preparation of glycopeptides derived from pooled human newborn meconiums inhibited the attachment (up to 55%) of all three clinical isolates examined. The mild hydrolysis of fucosyl residues from the above mixture totally abolished its inhibitory potency. By using human milk oligosaccharide probes, the minimal structural requirement for activity was found to be the Fucal-*2Gal,p determinant (the H sugar sequence found on all blood group substances of the ABO [H] system). By contrast, the fucosylated determinants of the Lewis blood group system were found to be totally inactive. Total adhesion inhibitions were never obtained in the present

A number of lactose-binding lectins have recently been identified in the rat and mouse intestine, one of which corresponds to the C-terminal domain of IgE-binding proteins, originally identified in rat basophilic leukemia (RBL) cells and mouse 3T3 fibroblasts. In the present report, we describe the affinity purification of a rat intestinal lactose-specific lectin which binds murine IgE antibodies. This binding most likely occurs via the immunoglobulin carbohydrate chains, as it is inhibited by lactose. This intestinal lectin molecule is also immunologically related to the previously described IgE-binding protein (EBP) isolated from RBL cells, since it is recognized by antibodies raised against recombinant EBP. This intestinal form of EBP has a molecular mass of 17.5 kDa, which is much lower than that of its RBL cell analogue (31 kDa). The attachment of IgE to the mouse intestinal epithelium was demonstrated by immunohistochemistry, along with the presence of a corresponding mouse intestinal EBP. The carbohydrate-dependent nature of this attachment was established by demonstrating that IgE binding to mouse epithelium was specifically abolished by lactose (4 mM) and by a blood-group-A-active tetrasaccharide (0.2 mM), but not by mannose (10 mM). Finally, the association of IgE with the mouse intestinal epithelium was prevented by competition with the purified IgE-binding lectin isolated from rat intestine. Although the physiological function of this intestinal protein is still unknown, the finding that IgE binds to a lectin in the intestinal epithelium pinpoints a possible novel mechanism for the regulation of IgE-mediated disorders, such as food allergy.IgE, through its interaction with cell-surface receptors, plays a key role in triggering allergic disorders [l]. Many IgEbinding molecules have been described, including the highaffinity and the low-affinity receptors for the E chain, the IgEbinding factors and the newly discovered IgE-binding protein (EBP) [2]. This latter protein was first evidenced by translation of mRNA from rat basophilic leukemia (RBL) cells in Xenopus oocytes 131. This molecule was shown to exhibit an intrinsic IgE-binding activity and therefore was referred as cBP [4, 51. Interestingly, evidence has emerged that EBP has a carbohydrate-binding activity, because its binding to IgE can be reversed by lactose [6]. Furthermore, it was found to exhibit a high sequence similarity with the carbohydrate-binding protein 35 (CBP 35) [6], which is a galactose-binding lectin originally identified in mouse 3T3 fibroblasts [7] and also found in mouse lung [8]. Similarly, recent data indicate that the EBP is identical to a rat lung lectin (RL) of 29 kDa 19, 101, also known to be a [j-galactoside-binding protein. Moreover, recent work showed that Mac-2 antigen (a murine macrophage cell-surface marker) is a j-galactoside lectin of 32 kDa, which binds IgE and whose sequence is almost identical to those of CBP 35 and cBP [ll]. Finally, a human EBP has recently been described, whose sequence exhibits extensive ...

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