Bovine myelin basic protein: immunochemical specificity examined by the macrophage migration inhibition test

Guinea pigs were injected with saline or with one of the following antigens incorporated into Freund's complete adjuvant: Bovine myelin basic protein (MBP), lysozyme, carboxymethylated lysozyme, or a crude commercial calf thymus histone preparation. Examination of the migration of peritoneal cells from these animals in the presence (50 microgram/ml) or the absence of the antigens revealed, at most, a slight one-way form of cross-reactivity between MBP on the one hand and the histone preparation--and possibly also lysozyme--on the other. This was observed only with cells from animals injected with the two last-mentioned antigens. Cells from animals sensitized with either histone or lysozyme mixed with poly AU instead of Freund's complete adjuvant were also slightly inhibited in their migration by the bovine MBP. Cells from animals injected with complete Freund's adjuvant alone or with the purified protein derivative of tuberculin (PPD) in poly AU did not react to MBP. Thus, in contrast to the high degree of internal cross-reactivity shown previously MBP shows a low degree of cross-reactivity with either ordered or unordered forms of some unrelated basic proteins.