| Abstract: | It was shown previously, that an antiserum directed against highly purified fractions of migration inhibitory factor inhibits delayed hypersensitivity reactions in vivo and in vitro. Using radiolabeling techniques we determined that the anti-lymphokine serum reacted primarily with three lymphocyte activation products (m.w. 60,000, 45,000, and 30,000) all of which had a similar isoelectric point of 5.2. The cellular origin of this material was investigated. It was found that activated B cells, B leukemia cells (L2C), and growing fibroblasts produced material of a similar m.w. as analyzed on SDS-PAGE. No cross-reaction was found with radiolabeled products of activated murine and human lymph node cells and of SV 40-infected African green monkey kidney cells. The isoelectric point of the reactive material from B cells, leukemia cells, and fibroblasts was determined at 5.2. In addition to material with pI 5.2, lymph node cells also produced material with pI 3.5 to 4.5, which focused at pH 5.0 to 5.4. After neuraminidase treatment macrophage migration inhibitory activity in fibroblast culture supernatants could be absorbed specifically to insolubilized anti-lymphokine antibody. These findings suggests that lymphoid and nonlymphoid cells are capable of producing molecules whose physicochemical and functional properties appear to be identical. |
