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ARS Home » Midwest Area » Ames, Iowa » National Animal Disease Center » Ruminant Diseases and Immunology Research » Research » Publications at this Location » Publication #71481
Title: GROUP B STREPTOCOCCUS ADHERE TO BOVINE POLYMORPHONUCLEAR CELLS BY CD11/ CD18 DEPENDENT AND INDEPENDENT MECHANISMS

Author
item SMITH, L - UNIV OF NEW HAMPSHIRE
item Kehrli Jr, Marcus
item PISTOLE, THOMAS - UNIV OF NEW HAMPSHIRE

Submitted to: Society for Leukocyte Biology Meetings Proceedings
Publication Type: Abstract Only
Publication Acceptance Date: 8/1/1996
Publication Date: N/A
Citation: N/A

Interpretive Summary:

Technical Abstract: Group B Streptococcus (GBS) is the leading cause of neonatal meningitis and sepsis in the United States. The exact mechanism of adherence between phagocytic cells and GBS is unknown. Because complement and specific antibody may be decreased or absent in infected individuals, the adherence mechanisms were studied in the absence of such factors. In the absence of exogenous opsonins, GBS is able to adhere to mammalian phagocytes in a dose-dependent manner. Blocking studies with anti-bets 2 integrin monoclonal antibodies gave partial blocking of attachment between GBS and phagocytic cells indicating the involvement of other proteins. We used a bovine model of leukocyte adhesion deficiency (BLAD) to explore further the role of the beta 2 integrins. BLAD individuals are unable to express beta2 integrins on the surface of phagocytic cells. Flow cytometry studies indicated that at phagocyte:GBS ratios of 1:10, 1:100, and 1:1000 12.0, 49.0, and 89.0%, respectively, of bovine LAD polymorphonuclear cells (PMNs) had GBS attached. The number of GBS bound to the normal bovine controls showed an increase in the percent positive cells, 44.9, 98.0 and 99.9%, respectively; however, the mean fluorescence intensity of GBS binding to both the normal and LAD bovine PMNs was similar at PMN:GBS ratios of 1:10 and 1:100 indicating that the normal and LAD PMNs bound GBS equally well. Because the beta2 integrins do not seem to be necessary for GBS binding, we investigated the involvement of other surface proteins from PMNs. We found that GBS binds to a 70-80 kD protein from the surface of both normal and LAD PMNs. These data indicate that adherence of GBS to phagocytes involves multiple receptors.