Kinetics of the humoral and cellular immune response of guinea pigs after injection of the synthetic adjuvant N-acetylmuramyl L-alanyl-D-isoglutamine: comparison with Freund complete adjuvant.

We studied the time course of humoral and cellular immunity of guinea pigs injected with the synthetic adjuvant N-acetylmuramyl L-alanyl-D-isoglutamine (MDP Pasteur, 10 microgram) in Freund incomplete adjuvant; the kinetics were compared with those obtained with Freund complete adjuvant (50 microgram of whole Mycobacterium butyricum). The antibody response to ovalbumin was faster and higher with MDP, but dropped sooner to a low level; the secondary response was, however, again higher for MDP than for Freund complete adjuvant. Cellular immunity, as measured by delayed hypersensitivity, and migration inhibition factor production werepositive for both adjuvants. The same response was followed in animals injected with MDPA, the nonamidated analog of MDP; the same kinetics as for Freund incomplete adjuvant were obtained for the primary response, but the secondary response was stronger and gave a positive delayed hypersensitivity reaction.