Signal requirements for the acquisition of tumoricidal competence by chicken peritoneal macrophages

The present study was conducted to determine the tumoricidal potential of chicken macrophages. Sephadex-elicited peritoneal macrophages from 6-wk-old Cornell K-strain White Leghorn females (B15B15) were used as effector cells against three different 51Cr-labeled tumor cell targets: LSCC-RP9 (B15B2), MDCC-CU14 (B19, C2), and MDCC-CU25 (B17B17). Quantification of tumoricidal activity was done in a 16-h, Cr-release assay. Macrophages collected at 12, 24, and 42 h post-Sephadex stimulation failed to kill any of the tumor cell targets. However, macrophages treated with concanavalin A stimulated splenic cell supernatants (lymphokines, LK) and lipopolysaccharide (LPS) were able to kill all three tumor cell targets in coculture experiments. Cell-free supernatants collected from LPS and LK alone or combination-treated macrophages demonstrated cytolytic activity for both RP9 and CU25 tumor cell targets. The results of the study, therefore, suggest that chicken macrophages acquire tumoricidal competence if treated with macrophage activation signals such as LK, or LPS or both.