B-cell-derived interleukin-1 (IL-1)-like factor. II. Sources, effects, and biochemical properties.

A variety of types of human B-cell lines were evaluated for their ability to produce interleukin 1 (IL-1)-like factors. All of the eight Epstein-Barr virus (EBV)-transformed B lymphocyte lines, three of four of the EBV+ lymphoma lines, only three of seven of the EBV- lymphoma lines, and none of the three tested myeloma lines secreted some IL-1 activity. The IL-1-like factor produced by the cell lines was detected on the basis of its thymocyte comitogenic and/or fibroblast proliferative activities. Injections of partially purified IL-1-like factor from one of the EBV-transformed B-lymphocyte lines also induced the appearance of an acute phase protein (haptoglobin) in the serum of C3H/HeJ mice. These biological activities are identical with those of monocyte-derived IL-1. Thymocyte comitogenic activity and fibroblast proliferation activity from one of the EBV-B cell line-derived IL-1-like activities were not dissociable by biochemical procedures, including HPLC gel filtration and HPLC anion-exchange chromatography. However, the IL-1-like factor from one of the EBV-B lymphocyte cell lines was larger in size (25 kDa) and more acidic (pI 5.5) than monocyte-derived IL-1.