TY - JOUR
T1 - Specific antibody promotes opsonization and PMN-mediated killing of phagocytosis-resistant Enterococcus faecium
AU - Rakita, Robert M.
AU - Quan, Van C.
AU - Jacques-Palaz, Karen
AU - Singh, Kavindra V.
AU - Arduino, Roberto C.
AU - Mee, Mee
AU - Murray, Barbara E.
N1 - Funding Information:
This work was supported by Grants-in-Aid from the American Heart Association, Texas Affiliate and National (to R.M.R.) and NIH Grant AI42399 (to B.E.M.). Monosaccharide analysis at the Complex Carbohydrate Research Center was supported in part by the NIH-funded Resource Center for Biomedical Complex Carbohydrates (NIH Grant P41-RR05351). We thank M. Mariscalco, R. Todd, R. Rothlein, and I. Gigli for providing antibodies; R. Jordon for use of the fluorescence microscope; F. Wold for assistance with carbohydrate purification; R. Merkle for monosaccharide analysis; and I. Gigli for helpful comments. A portion of this work was presented at the 1995 American Federation for Clinical Research meeting, San Diego, CA (J. Invest. Med. (1995) 43 (Suppl. 2), 288A).
PY - 2000/8
Y1 - 2000/8
N2 - Many clinical isolates of Enterococcus faecium are resistant to neutrophil (PMN)-mediated phagocytosis and killing in the presence of normal human serum. We have now examined the ability of specific polyclonal rabbit antibodies to promote opsonization and killing of phagocytosis-resistant E. faecium. Immune rabbit serum generated against formalin-killed E. faecium TX0016, a phagocytosis-resistant strain, markedly promoted binding of TX0016 organisms to PMNs and PMN-mediated killing. These effects were dramatically reduced by (a) adsorption of immune serum with E. faecium TX0016, but not by adsorption with a strain of E. faecium susceptible to phagocytosis, and (b) incubation of immune serum with carbohydrate purified from TX0016, but not by incubation with a surface protein extract from TX0016. IgG purified from immune serum was unable by itself to promote bacterial binding to PMNs. However, specific IgG was able to promote binding to PMNs and PMN-mediated killing in the presence of normal human serum as a complement source, as were F(ab')2 and Fab fragments produced from it, and the alternative pathway of complement was sufficient to promote IgG- and F(ab')2-mediated opsonization. PMN complement receptor type 3, but not complement receptor type 1, was involved in bacterial binding to PMNs induced by the combination of F(ab')2 fragments and normal human serum. These results suggest that opsonization by antibodies potentially directed against bacterial carbohydrate, in conjunction with complement activation, has an important role in the host defense against phagocytosis-resistant E. faecium. Copyright (C) 2000 Federation of European Microbiological Societies.
AB - Many clinical isolates of Enterococcus faecium are resistant to neutrophil (PMN)-mediated phagocytosis and killing in the presence of normal human serum. We have now examined the ability of specific polyclonal rabbit antibodies to promote opsonization and killing of phagocytosis-resistant E. faecium. Immune rabbit serum generated against formalin-killed E. faecium TX0016, a phagocytosis-resistant strain, markedly promoted binding of TX0016 organisms to PMNs and PMN-mediated killing. These effects were dramatically reduced by (a) adsorption of immune serum with E. faecium TX0016, but not by adsorption with a strain of E. faecium susceptible to phagocytosis, and (b) incubation of immune serum with carbohydrate purified from TX0016, but not by incubation with a surface protein extract from TX0016. IgG purified from immune serum was unable by itself to promote bacterial binding to PMNs. However, specific IgG was able to promote binding to PMNs and PMN-mediated killing in the presence of normal human serum as a complement source, as were F(ab')2 and Fab fragments produced from it, and the alternative pathway of complement was sufficient to promote IgG- and F(ab')2-mediated opsonization. PMN complement receptor type 3, but not complement receptor type 1, was involved in bacterial binding to PMNs induced by the combination of F(ab')2 fragments and normal human serum. These results suggest that opsonization by antibodies potentially directed against bacterial carbohydrate, in conjunction with complement activation, has an important role in the host defense against phagocytosis-resistant E. faecium. Copyright (C) 2000 Federation of European Microbiological Societies.
KW - Antibody
KW - Complement
KW - Enterococcus faecium
KW - Neutrophil
KW - Phagocytosis
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U2 - 10.1016/S0928-8244(00)00169-3
DO - 10.1016/S0928-8244(00)00169-3
M3 - Article
C2 - 10891652
AN - SCOPUS:0034097921
VL - 28
SP - 291
EP - 299
JO - FEMS Immunology and Medical Microbiology
JF - FEMS Immunology and Medical Microbiology
SN - 0928-8244
IS - 4
ER -