EFFICACY OF VARIOUS MONOCLONAL ANTIBODIES (Ab) AGAINST E. COLI (EC)

Abstract

The morbidity and mortality associated with neonatal EC infections have remained significant despite advances in antimicrobial chemotherapy. To investigate the feasibility of immunotherapeutic approaches, we evaluated 3 different murine monoclonal IgM Ab against a K1 EC strain in the newborn rat model: (1) Ab to group B meningococcal carbohydrate (K1 Ab), (2) Ab to the LPS of the same K1 EC(LPS Ab), and (3) Ab to lipid A. At 5 days of age, each litter was divided into 4 groups. Each group received intraperitoneally one of the above or murine IgM monoclonal Ab to the LPS of P.aeruginosa (control) in a dose of 50 ul/10 gm and subcutaneously EC (LD100). Blood and CSF specimens were obtained daily and mortality recorded for 5 days. Results are summarized as protective efficacy against death. K1 and LPS Ab provided 100% protection neat and at 10-1. All control animals died. These studies indicate that monoclonal Ab to K1 polysaccharide and Ab to the LPS of EC are highly protective against K1 EC and combinations of these two further enhance the efficacy.