Characterization of macrophage cell line A640-BB-2: A640-BB-2 resembles peritoneal exudate macrophages in cell morphology, tumor cell recognition, responsiveness to immunomodulator OK-432 and lysosomal enzyme activity.

Characteristics of mouse macrophage (MP) cell lines A640-BB-2, J774.1 and P388D1 and mouse peritoneal exudate MPs were studied and compared in cell morphology, ability to recognize tumor cells in the presence and absence of OK-432 known to activate MPs, and in lysosomal enzyme activity. In A640-BB-2 cells and exudate MPs, cell surfaces showed a few ridge-like processes and microvilli; spontaneous cytotoxicity was moderate against tumor target L929, and little or absent against targets SV3T3, B-16 and U937; and lysosomal enzyme activity of nonspecific esterase, acid phosphatase, and beta-glucuronidase was high. After culture in the presence of OK-432, A640-BB-2 cells and exudate MPs showed more extensive spreading with larger surface areas and with increased numbers of ridge-like processes and microvilli, and their cytotoxicity against target L929 became more extensive. The stable soluble factor did not participate in the mechanism of cytotoxicity against target L929 mediated by A640-BB-2 cells and exudate MPs. J774.1 and P388D1 cells were different from exudate MPs in cell morphology and ability to recognize tumor cells when cultured either with or without OK-432, and in lysosomal enzyme activity. A640-BB-2 cells seem to be useful in studying MP-tumor cell interaction and MP activation, and in detecting the trace biological activating factor of MPs.