Abstract
Summary
Injection of 15 μg of a haptenazoprotein, such as p-aminobenzoic acid diazotized to hen egg albumin, in Freund's adjuvant, into footpads of guinea pigs produces delayed hypersensitivity in 5 days and circulating antibody in 10-11 days after sensitization. Injection of 1 μg of such conjugate in saline produces delayed hypersensitivity but no detectable circulating antibody. Specificity of delayed hypersensitivity is oriented toward the protein; that of circulating antibody, toward the hapten. When a primary dose of 1 μg in saline of protein, azoprotein or heterologous hapten-homologous protein is followed by a secondary dose of hapten-homologous protein, antibody response to the hapten is accelerated. A primary sensitizing dose of hapten, such as p-aminobenzoic acid (PABA) + protein such as hen egg albumin (HEA), followed by a secondary dose of the same hapten attached to heterologous protein, does not result in accelerated response to the hapten. These phenomena are explained if delayed hypersensitivity is considered an early step in antibody synthesis.
Technical assistance of Jane Nishio, Aspascia Cobure, and Leroy F. Peel is gratefully acknowledged.
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