Interactions between human serum proteins and oral streptococci reveal occurrence of receptors for aggregated beta 2-microglobulin

Representative strains of oral streptococci were tested for Fc immunoglobulin G (IgG) reactivity by two different techniques, agglutination of rabbit-IgG sensitized sheep erythrocytes and uptake of human and rabbit 125I-radiolabeled IgG. None of the S. mutans serotypes a through e reacted with the Fc region of either human or rabbit IgG. Additionally, other streptococci such as S. sanguis, S. salivarius, S. faecalis, and S. mitis failed to show appreciable Fc reactivity as assayed by these techniques. The group A, C, and G streptococci, previously shown to possess Fc reactivity, proved to be reactive in these experiments, as did a protein A-containing strain of Staphylococcus aureus.

Section: Discussion Two Different Techniques Agglutination Ofmentioning

confidence: 99%

Examination of Streptococcus mutans for immunoglobulin G Fc reactivity

Shea¹,

Ferretti²

1981

“…IgA in void volume fractions that reacted with bacteria most likely represents small amounts of aggregated IgA. Secretory component is not involved in nonspecific reactions of 11S IgA with streptococci (S. Suzuki and R. R. A. Coombs, unpublished data), and nonspecific IgA binding is uncommon with oral streptococci (14). There was so little nonspecific binding of secretory IgA to the test bacteria that we were able to demonstrate specific binding of small amounts of colostral antibodies to B.…”

Section: Discussionmentioning

confidence: 67%

Reaction of human colostral and early milk antibodies with oral streptococci

Eggert¹,

Gurner²

1984

Colostrum or early breast milk or both from each of 16 healthy women contained agglutinating antibodies for all normal streptococcal inhabitants of the human oral cavity (S. mutans, S. sanguis, S. mitis, and S. salivarius), including those which colonize the neonatal oral cavity in significant numbers. Agglutination correlated with the amount of immunoglobulin A (IgA) binding to bacterial surfaces as measured by mixed reverse passive antiglobulin hemagglutination. Surprisingly, colostral IgA agglutinated our control organism, Brucella abortus. Low levels of colostral or milk IgM and IgG antibodies also reacted with all of the test bacteria. Absorption studies with an enzyme-linked immunosorbent assay showed that a proportion of antibodies in colostrum and early milk is specific for each of the different oral streptococci. Fractionation on Sepharose 4B indicated that 11S secretory IgA is the predominant form of colostral and milk antibody for all of the test bacteria, including B. abortus. No evidence was found that reactions other than antigen-antibody reactions resulted in binding of colostral immunoglobulins by any of the test bacteria. The spectrum of antibacterial antibodies in human colostrum and early milk is of interest in understanding the role of secretory antibodies both during immediate postnatal development and in subsequent development and control of a normal gastrointestinal tract flora. This role of secretory

“…P2m is also present in saliva and other body fluids (2,3,11,28). Previous studies have shown that aggregates, but not monomers, of ,B.m bind to bacteria (12,21). Aggregation of P3m to high-molecular-weight complexes strongly increases the avidity of the interaction between bacteria and the ,B2m complexes.…”

mentioning

confidence: 99%

“…We have earlier demonstrated that aggregated P2-microglobulin (P2m) can interact with strains of oral streptococci (10,12). 132m is a low-molecular-weight protein occurring on surfaces of all nucleated cells as the light chain of the major histocompatibility antigens (for a review, see reference 3).…”

mentioning

confidence: 99%

Agglutination of Streptococcus mutans by low-molecular-weight salivary components: effect of beta 2-microglobulin

Ericson¹

1984

Self Cite

Radiolabeled monomeric human 02-microglobulin (0i2m) was tested for binding to Streptococcus mutans strains in buffers containing I mM calcium (Ca2+). Binding was seen to strains with a previously established binding capacity of aggregated 12m. Monomeric P2m agglutinated 012m-binding strains when Ca`was present. At Ca2+ concentrations of 1.4 mM, 0.032 jig of monomeric 132m per ml caused bacterial agglutination.