Production of Hypersensitivity in the Neonatal Mouse¹

When the neonatal mouse is injected intravenously with a single dose of antigen, followed next day by an intravenous injection of Bordetella pertussis phase I vaccine, the following events take place: a) blast cells and foci of mitotic activity are seen in the spleen and thymus, and antibody-producing cells are detectable by the Jerne plaque technique by the 4th day of age; b) marked anaphylactic sensitivity does not become evident until the 5th week, and then persists at a maximum to the 10th week of age; and c) the anaphylactic sensitivity is not correlated with 19S or 7S antibody, precipitating antibody or antigen-binding capacity of the serum.