Dendritic cell activating factor produced by mouse macrophage hybridoma

Enhancement of antigen-presenting function of dendritic cells with culture supernatants of mouse peritoneal macrophages stimulated with certain particulate substances

The production from murine resident peritoneal macrophages (M phi) of a soluble factor, which was capable of enhancing the antigen-presenting (AP) function of dendritic cells (DC), was examined. The supernatants of peritoneal M phi (M phi sup) were prepared by culturing peritoneal M phi with particles, i.e., zymosan A, latex, and sheep red blood cells (SRBC), or antigen-antibody (Ag-Ab) complexes such as keyhole limpet hemocyanin (KLH)-anti-KLH, ovalbumin (OVA)-anti-OVA, and SRBC-anti-SRBC complexes. When exposed to M phi sup during antigen pulsing DC induced a marked antigen-specific T cell proliferation, relative to DC treated with the supernatants from M phi cultured without stimuli (control sup). On the other hand, M phi sup-treated splenic M phi stimulated antigen-specific T cell activation to almost the same extent as did splenic M phi treated with control sup. These results indicated that peritoneal M phi elaborated a soluble factor which preferentially enhanced the AP capacity of DC when stimulated with particles or Ag-Ab complexes. Analytical gel filtration of M phi sup revealed that the factor had an apparent molecular weight of 27,000 daltons which was distinct from interleukin 1.