Cell-free culture supernatant fluids rich in macrophage-activating factor (MAF) activity were obtained from mitogen-stimulated human peripheral blood mononuclear leukocytes (MNL). The MAF preparations were incubated with human peripheral blood monocytes, rat alveolar macrophages (AM), and mouse peritoneal exudate macrophages (PEM). Only human monocytes were rendered tumorilytic against the huma...

Macrophage-activating factor (MAF) was obtained from cultures of normal F344 rat lymphocytes incubated with insoluble concanavalin A. The MAF rendered macrophages from normal C57BL/6 mice cytotoxic against the syngeneic B16 melanoma and the allogeneic AC 15091. At the same time, normal syngeneic or allogeneic embryo cells were unharmed, even in the presence of susceptible tumor cells. Optimal M...

This report describes a murine amniotic fluid (MAF) immunosuppressive factor that has properties similar to transforming growth factor beta (TGF-beta). The MAF factor exhibits TGF-beta-like activity in stimulating soft agar colony formation by AKR-2B cells and inhibiting thymidine uptake by Mv1Lu cells. We demonstrate that both the immunosuppressive and TGF-beta-like activities of the MAF facto...

Lens development is regulated by a variety of transcription factors with distinct properties. The lens-specific transcription factor, L-Maf, is essential for lens formation and induces lens-specific markers, such as the crystallin genes. In this study, we analyzed the mechanism by which L-Maf regulates delta-crystallin expression. Misexpression of L-Maf in the head ectoderm of lens placode-form...

The small Maf transcription factor proteins bind to Maf Recognition Elements (MAREs) by dimerizing with CNC proteins or themselves. We undertook experiments to clarify the functional relationship between the small Mafs and their partners in vivo. Embryos expressing abundant transgene-derived MafK died of severe anemia, while lines expressing lower levels of small Maf lived to adulthood. Megakar...

It is not clear why the development of protective Th2 cells is poor in type 1 diabetes (T1D). c-Maf transactivates the IL-4 gene promoting Th2 cell development; therefore, abnormalities in c-Maf may contribute to reduced IL-4 production by CD4 cells from nonobese diabetic (NOD) mice. In this study we demonstrate that despite normal expression, c-Maf binds poorly to the IL-4 promoter (IL-4p) in ...

IL-27 has recently been identified as a differentiation factor for the generation of IL-10-producing regulatory type 1 (Tr1) T cells. However, how IL-27 induces the expansion of Tr1 cells has not been elucidated. In this study we demonstrate that IL-27 drives the expansion and differentiation of IL-10-producing murine Tr1 cells by inducing three key elements: the transcription factor c-Maf, the...

Activation of mouse peritoneal exudate macrophages, as evidenced by destruction of the intracellular protozoan parasite Leishmania enriettii, was obtained by incubation with supernates from concanavalin A (Con A)-stimulated syngeneic spleen cells. Parasites were not destroyed in macrophages exposed to control media. Supernate-induced activation was independent of the presence of Con A. The acti...

Human peripheral blood mononuclear cells from normal donors obtained by separation on a Percoll gradient were incubated with free or liposome-entrapped lymphokines produced from concanavalin A-stimulated lymphocytes and then were tested for cytotoxic activity against tumor cells. The treated monocytes lysed tumorigenic melanoma and glioblastoma target cells, but had no effect on three types of ...