Journal of Neuroimmunology, 13 (1986) 109-113 109 Elsevier JNI 00436 Short Communication Effect of Macrophage Activators on the Phagocytosis of Mycobacteria by Schwann Cells Hamid Band * and G.P. Talwar Deparment of Pharmacology. A ll-lndia Institute of Medical Sciences, and National Institute of Immunology, New Delhi-llO029 (India) (Received 31 March, 1986) (Revised, received7 July, 1986) (Accepted 7 July, 1986) Summary Concanavalin A-induced lymphokines decreased the phagocytosis of t4C- acetate-labelled Mycobacterium w by 33B rat Schwannoma cells while increasing the phagocytosis by macrophages. This suggests that Schwann cells are responsive to lymphokines. Phorbol myristate acetate decreased the phagocytosis in Schwannoma cells but increased that in macrophages. Schwann cells, thus, respond to stimulants of macrophage phagocytosis in a manner opposite to that of macrophages. Key words: Schwann cells- Phagocytosis- Lymphokines- Macrophage activators - Mycobacteria The preferred target cells for Mycobacterium leprae, the causative agent of human leprosy, are the phagocytic cells of the monocytic lineage and the Schwann cells of the peripheral nerve (Bjune et al. 1983). The latter feature of M. leprae is responsi- ble for the unique property of this organism to cause peripheral nerve damage (Antia 1982). We have previously shown that the uptake of mycobacteria by a clonal rat Schwannoma cell line, 33B, is a useful system to study certain aspects of mycobacteria-Schwann cell interaction in vitro. Like normal Schwann cells and macrophages, these cells avidly phagocytose mycobacteria (Band et al. 1986a). Moreover, the mechanism of phagocytosis by Schwannoma cells showed a close * Present address: Division of Immunogenetics, Dana Farber Cancer Institute, and Department of Pathology, Harvard Medical School, 44 Binney Street, Boston, MA 02115, U.S.A. 0165-5728/86/$03.50 ,~21986 Elsevier Science Publishers B.V. (Biomedical Division)