Abstract
Mice infested at birth with the mouse mite Myocoptes musculinus developed positive skin tests to mite antigens at the age of 5 weeks. Serum IgE antibodies directed against mite antigens were first detected at 6 weeks of age and high levels of IgE were present as long as 1 year later. Similar kinetics of IgE formation were observed in mice infested as adults. Mast cell degranulation by mite extract was demonstrated in connective tissue obtained from the skin of mite infested mice.