OPSONIC ANTIBODIES TO STAPHYLOCOCCUS-EPIDERMIDIS - IN-VITRO AND IN-VIVO STUDIES USING HUMAN INTRAVENOUS IMMUNE GLOBULIN

Staphylococcus epidermidis is a major cause of nosocomial infections, including sepsis in premature infants. Intravenous immune globulin (IV IG) has been used to prevent neonatal sepsis, but efficacy has varied in different clinical trials. The role of IgG antibody in immunity to S. epidermidis was studied using an opsonophagocytic assay and a lipid -emulsion-induced lethal model of neonatal S. epidermidis sepsis. Opso nic antibody to S. epidermidis varied between IVIG preparations and be tween lots: Lots with greater than or equal to 90% opsonic activity pr omoted bacterial clearance from blood and significantly enhanced survi val when compared with lots with less than or equal to 50% opsonic act ivity. Absorption of IVIG with S. epidermidis removed in vitro opsonic and in vivo protective activity. These studies suggest that opsonic a ntibody may play an important role in S. epidermidis immunity in immun ocompromised patients, such as premature infants. Standard IVIG, howev er, may not provide therapy effective in preventing S. epidermidis inf ections, as many IVIG lots contain insufficient levels of opsonic S. e pidermidis antibody.