The interaction of Staphylococcus epidermidis slime with human neutrophils (PMN) was examined by using isolated slime and allowing bacteria to elaborate slime and other extracellular products in situ. S. epidermidis slime was found to contain a chemoattractant. Incubation of PMN with 50 ,ug or more of slime per ml inhibited subsequent chemotaxis of the PMN to n-formyl-methionyl-leucyl-phenylalanine by 27% and to zymosanactivated serum by 44 to 67% with increasing slime concentrations. S. epidermidis slime stimulated little degranulation of untreated PMN. After pretreatment of PMN with 5 ,ug of cytochalasin b per ml, slime predominantly induced release of specific granule contents (33.8% lactoferrin release by 250 ,ug of slime per ml versus 10% myeloperoxidase release by 250 ,ug of slime per ml). By a surface phagocytosis assay, PMN uptake of radiolabeled S. epidermidis which were incubated for 18 h on a plastic surface for slime expression was less than that for S. epidermidis adhered to the plastic for 2 h or grown in unsupplemented nutrient broth. These results suggest that S. epidermidis slime interaction with PMN may be potentially detrimental to host defense and may contribute to the ability of this organism to persist on surfaces of foreign bodies in the vascular or central nervous system.
1 1 29 CHILDHOOD: NATURAL HISTORY OF BAcTEREMIA AND ANTI-GENEMIA. Leonard J . La Scolea, J r . , Santiago V. Kosales, Pearay L. Ogra, SUNY a t Buffalo, Children's Hospital of Buffalo, Department of P e d i a t r i c s , Buffalo, New York.Groups of children, up t o 7% years of age, with meningitis, e p i g l o t t i t i s o r s e p t i c a r t h r i t i s due t o HIB were t e s t e d f o r t h e presence and l e v e l s of bacteremia, capsular polyribophosphate (PRP) antigenemia and development of HIB s p e c i f i c antibody i n serum following onset of a c u t e i l l n e s s . The q u a n t i t a t i v e d i r e c t p l a t i n g method and i n d i r e c t ELISA were used t o determine t h e numb e r of organisms, PRP, and immunoglobulin c l a s s of BIB s p e c i f i c antibody. Bacteremia and antigenemia were detected i n a l l pat i e n t s immediately a f t e r onset of i l l n e s s . Although bacteremia c l e a r e d promptly a f t e r a n t i b i o t i c therapy, PRP could be detected i n serum up t o 96 days a f t e r onset of i l l n e s s . The presence of a low magnitude bacteremia (<300 organismslml) c o r r e l a t e d t o a maximum concentration of 10 ng/ml of PRP. On t h e o t h e r hand, b a c t e r i a l counts of l x 1 0~/ m l c o r r e l a t e d t o >I000 n g / d of PRP. Despite t h i s c o r r e l a t i o n , p e r s i s t e n c e of PRP antigenemia appeared t o b e independent of a ) magnitude of antigenemia observed during t h e a c u t e phase, b) development of antibody, o r c) p a t i e n t ' s age a t time of i l l n e s s . However, serum antibody response was observed i n convalescent samples only i n s u b j e c t s who exhibited peak PRP concentrations < I 0 ng/ml (p=0.006). These f i n d i n g s sugg e s t a d i r e c t c o r r e l a t i o n between t h e magnitudes of bacteremia and antigenemia and t h a t a n t i g e n may p e r s i s t f o r long periods even i n t h e presence of antibody and the l e v e l of antigenemia s i g n i f i c a n t l y influences t h e convalescent antibody response. REGULATION OF INTERFERON RECEPTOR EXPRESSION ON1130 HUMAN LYMPHOCYTES. Allan S. Lau, Greg E. Hannigan, Melvin H. Freedman and Bryan R.G. Williams. Spon. by R. Gold). Research I n s t i t u t e , H o s p i t a l f o r Sick Children, Toronto, Ontario.I n t e r f e r o n s (IEN) e l i c i t a n t i v i r a l and a n t i n e o p l a s t i c a c t i v i ti e s by binding t o s p e c i f i c r e c e p t o r s on the c e l l s u r f a c e . The binding of IFN t o human lymphocytes was studied using IFNa'j (Schering-Plough) l a b e l l e d t o high s p e c i f i c a c t i v i t y with 2 5~. P e r i p h e r a l Blood Lymphocytes CPBL) from 8 a d u l t x a l u n t e e r s and t o n s i l l a r B c e l l s from 4 c h i l d r e n , who underwent e l e c t i v e tonsillectomy, were s t u d i e d . S p e c i f i c 1 2 5~-~~~a 2 binding isotherms were generated on t h e s e c e l l s . When c e l l s were preincubated i n v i t r o w i t h low c o n c e n t r a t i s of unlabelled IFNcr2 f o r 20h, s...
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