Antibacterial activity of a human monoclonal antibody to haemophilus influenzae type B capsular polysaccharide.

Human splenic lymphocytes were fused with a new mutant human myeloma cell line (HFB-1) to produce hybridomas that secrete human monoclonal antibodies. A cloned hybridoma line was selected that secretes IgG antibodies reactive with Haemophilus influenzae type b polyribosylribitolphosphate (PRP) capsular polysaccharide. This human monoclonal antibody was active in an in-vitro neutrophil-mediated bactericidal assay, and provided significant protection in an animal model of H. influenzae type b disease. Human monoclonal antibody to H. influenzae type b may have prophylactic value in man, particularly in infants who do not produce protective antibody after active immunisation with PRP.