AIM: Study the effect of ribosomal proteins of respiratory bacteria composing the basis of the immune-modulating preparation ribomunil on adhesive properties of buccal epithelium of healthy donors, and carry out comparison of this parameter during use of other bacterial products. MATERIALS AND METHODS: Various amounts of bacterial ribosomal proteins, Escherichia coli (serotype O127:B8) and one-day Staphylococcus aureus (strain 5983) culture supernatant were added to "buccal epitheliocytes--candida" system and incubated. Buccal cells were washed after the incubation from non-bound candida and differentiated microscopically by the amount of cells with various levels of candida adhesion. Separate effect of ribosomal proteins on buccal cells and candida was studied, as well as their impact on the production of secretory products of buccal cells. RESULTS: Buccal epitheliocytes in control adhered on average 14.6 candidiasis cells. After incubation with bacterial ribosomal proteins the index decreased by 2.3 +/- 0.2 times. During separate addition of ribomunil to buccal cells and candida, ribosomal bacterial proteins were shown to have effect only on epitheliocytes. Activity of ribosomal proteins had a selective character, as shown by the lack of effect under the influence of S. aureus supernatant on buccal cells as well as an increase of adhesion under the influence of lipopolysaccharide on epitheliocytes. Viability of cells in all the cases remained at a level of 90 - 98%. Buccal cells during contact with ribomunil produced a complex of soluble mediators that took part in its blocking effect. CONCLUSION: The increase of stability of mucosal tract to microbial adhesion is an element of innate immunity and may be one of the components of immune-protecting effect of bacterial ribosomal proteins.