“…Phase I strains of Bordetella pertussis produce two distinct hemagglutinins (3, 15,16). The lymphocytosis-promoting factor hemagglutinin (LPF) appears as spherical structures 6 nm in diameter by electron microscopy (4,15,22), has a relatively low hemagglutinating activity, and induces a variety of biological responses, including leukocytosis and lymphocytosis, histamine sensitization, lethality, mitogenicity, adjuvant effects, and potentiation of insulin secretion (3,15,16,22,24). Munoz and Bergman refer to LPF as pertussigen (26), and it is now clear, based on biological activities (24), antigenic properties (7,21), and chemical and physical properties (15,16,22) that LPF is also identical to the islet-activating protein also isolated from B. pertussis (32,33).…”