CHARACTERIZATION OF LYMPHOCYTE-ACTIVATING FACTOR (LAF) PRODUCED BY A MACROPHAGE CELL LINE, P388D1 .2. BIOCHEMICAL CHARACTERIZATION OF LAF INDUCED BY ACTIVATED T-CELLS AND LPS

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  • 1 January 1978
    • journal article
    • research article
    • Vol. 120  (5) , 1504-1508
Abstract
Unstimulated [mouse macrophage] P388D1 cells, as well as P388D1 cells stimulated with PHA[phytohemagglutinin]-activated guinea pig T [thymus-derived] lymphocytes or LPS [lipopolysaccharide], produced a lymphocyte activating factor (LAF). In order to have a chemical basis for comparing this LAF with the LAF produced by normal macrophages, several biochemical characteristics of the P388D1-derived LAF were analyzed. Sephadex G-75 chromatography of concentrated LAF-containing supernatants from cultures of unstimulated and T cell stimulated P388D1 cells demonstrated that the cell line LAF had a MW of approximately 16,000. On DEAE cellulose, the T cell-induced LAF fractionated into at least 3 major peaks and 1 minor peak. By using hydroxylapatite chromatography, 2 of the major peaks of LAF activity were separated from residual contaminating Lowry positive material. LPS-stimulated P388D1 also produced LAF with a MW of 16,000. However, the LPS-induced LAF appeared to lack 1 of the DEAE peaks of LAF activity observed with the T cell-derived LAF. In contrast to LPS, T cells may induce the synthesis and/or release of an additional LAF component or enzymatically modify 1 or more of the LAF species that are produced in response to both stimulants. The P388D1-derived LAF appears to be similar in size and charge to the LAF produced by normal macrophages.