Immunoprotection of rats against Haemophilus influenzae type B disease mediated by monoclonal antibody against a haemophilus outer-membrane protein.

Infant rats passively immunised with a murine monoclonal antibody against a cell-surface-exposed outer-membrane protein of Haemophilus influenzae by b (Hib) were protected against systemic Hib disease induced by intraperitoneal injection of virulent Hib cells. The immunoprotection mediated by this monoclonal antibody was specific for Hib strains carrying the protein antigenic determinant that it recognised; the antibody gave no protection against disease when passively immunised animals were challenged with a heterologous Hib strain. The immunoprotection given by an antibody against a Hib outer-membrane protein suggests that Hib outer-membrane proteins have potential for development as Hib vaccines.