Abstract
We developed an efficient method for production of experimental polyarthritis. Native collagen (type II) from human costal cartilage was emulsified with incomplete Freund's adjuvant (IFA) containing the synthetic adjuvant, N-acetylmuramyl-L-alanyl-D-isoglutamine (MDP), and injected into one hind footpad of the PVG/c rat. This method reproducibly induced severe arthritis with high incidence, whereas the collagen alone in IFA produced mild arthritis with low incidence. MDP alone in IFA was shown to be minimally arthritogenic under identical conditions.
MDP and its adjuvant-active analogs stimulated macrophages to produce a soluble factor (T cell activating factor, TFA) which was shown to be efficient in antigeninduced MIF production of immune lymphocytes as well as mitogen-induced proliferation of T lymphocytes. The in vitro system developed in this study should contribute to the understanding of the target cells for adjuvant activity of MDP. Moreover, the Mφ factor produced by stimulation with MDP may be advantageous for characterization of the factor, since MDP of low molecular weight appeared to be easily removed from the culture sup.
