Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.1.4.3 (phospholipase C)
 18,461 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The detection of antibody to S aureus in human serum can aid in the management of staphylococcal diseases [1]. RIAs and ELISAs can detect low levels of antibody and demonstrate increased antibody production during serious staphylococcal infections [2,3]. We compared four S aureus constituents--cell-wall peptidoglycan and teichoic acid, and extracellular alpha-toxin and nuclease--as antigens in a sensitive ELISA. The value of testing more than a single serum sample was also determined. Elevated IgG antibody to peptidoglycan, present in one or more serum samples of 13 (50%) of 26 patients with complicated bacteremia, was found to be the most sensitive test. All 26 patients had a significant IgG antibody response to peptidoglycan. Three (27%) of 11 patients with uncomplicated bacteremia had elevated levels of antibody to peptidoglycan in their serum, and seven (64%) showed a significant change in titer when serial serum samples were tested. Maximum detection rates for the other antigens in complicated and uncomplicated bacteremia were, respectively, 62% and 37% for teichoic acid, 38% and 37% for nuclease, and 54% and 13% for alpha-toxin. In single serum samples, the detection rate for all four antigens marginally improved the results, with detection rates of 62% and 36% for complicated and uncomplicated bacteremia, respectively. Cross-reactive antibody to peptidoglycan but not to the other three antigens was present in six (75%) of eight patients with long-standing subacute bacterial endocarditis due to either viridans streptococci or Staphylococcus epidermidis (data not shown).(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Serology of Staphylococcus aureus infections using multiple antigens and serial serum samples. 661 82

We have sought to elucidate the responses of human peripheral blood neutrophils to antigenic surfaces complexed with human specific IgA antibodies obtained either as myeloma proteins that recognize staphylococcal alpha-toxin, or from the serum of patients with subacute bacterial endocarditis due to Streptococcus mutans, or from colostrum. In contrast to IgG, IgA antibodies bound to antigen-coated fluorescent microspheres, and subsequently exposed to complement (or not), did not promote phagocytosis, as measured by flow cytometric enumeration of cell-associated microspheres. Instead, IgA antibodies interfered with complement-dependent phagocytosis mediated by IgG antibodies. These properties were shown by different forms of IgA antibodies, including serum and secretory IgA, as well as by monoclonal or polyclonal antibodies. Neutrophils did not respond to the production of superoxide to IgA antibodies complexed with antigen-coated microspheres or with antigen deposited on a solid surface and IgA antibodies suppressed IgG antibody- and complement-mediated superoxide release. However, neutrophils pretreated with interleukin-8 ingested IgA-opsonized microspheres and released superoxide when exposed to IgA antibody-antigen complexes. IgG antibody-antigen complexes did not stimulate increased superoxide release in interleukin-8-treated neutrophils. These findings were consistent with a selective increase in the surface expression of Fc alpha R by interleukin-8-treated neutrophils. We conclude that IgA antibodies interfere with the phagocytic activities of normal circulating human neutrophils and may promote these activities in inflammatory neutrophils activated by interleukin-8 in which Fc alpha R is up-regulated.
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PMID:Dual function of human IgA antibodies: inhibition of phagocytosis in circulating neutrophils and enhancement of responses in IL-8-stimulated cells. 779 Jul 70