OVA peptide 323-339 represents a T and B cell epitope of OVA, which is important in the generation and development of immediate hypersensitivity responses in BALB/c mice. Daily aerosolization of OVA 323-339 for 20 minutes over a period of 10 days has been as effective in the stimulation of a serum anti-OVA IgE antibody response as sensitization to native OVA by the same route. After sensitization to native OVA, the majority of the IgE anti-OVA response is directed against OVA peptide 323-339.