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Nitric oxide production by peritoneal macrophages of Mycobacterium bovis BCG‐infected or non‐infected mice: regulatory roles of T lymphocytes and cytokines
Author(s) -
Saito Shinji,
Nakano Masayasu
Publication year - 1996
Publication title -
journal of leukocyte biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.819
H-Index - 191
eISSN - 1938-3673
pISSN - 0741-5400
DOI - 10.1002/jlb.59.6.908
Subject(s) - immune system , biology , macrophage , interleukin 12 , mycobacterium bovis , tumor necrosis factor alpha , antigen , immunology , microbiology and biotechnology , interferon gamma , cytokine , cytotoxic t cell , in vitro , mycobacterium tuberculosis , medicine , tuberculosis , biochemistry , pathology
Infection with Mycobacterium bovis bacillus Calmette‐Guerin (BCG) confers mice with strong abilities to produce nitric oxide (NO) and cytokines. Because the peritoneal macrophages taken from the mice immunized with live or heat‐killed BCG can produce NO without any accessory cells and stimulants, it is difficult to clarify the immune regulation on NO production by manipulating the macrophages. Therefore, we investigated the participation of immune T cells and cytokines in NO production by using in vitro co‐cultures of macrophages from non‐immune mice with T cells prepared from BCG‐infected mice in the presence or absence of a mycobacterial antigen, purified protein derivative (PPD). Although the non‐immune thioglycollate (TGB)‐elicited macrophages could not produce any detectable NO in the presence of PPD, supplementation of the macrophage cultures with CD4 + T cells prepared from BCG‐infected mice enabled the macrophages to produce NO. Immunocytostaining showed that the macrophages, but not the immune T cells, expressed inducible NO synthase (iNOS), indicating that they were NO producers. PPD could only induce NO production if there was cell‐cell contact of the CD4 + T cells in the immune cells and antigen‐presenting macrophages were required for the NO production in response to PPD; this interaction led to the production of soluble mediators that induced NO production by the TGB macrophages. NO production by the co‐cultured cells was abrogated by adding either anti‐interferon‐γ(IFN‐γ) or anti‐tumor necrosis factor α (TNF‐α) antibody. Furthermore, the roles of immune T cells and PPD could be replaced by adding recombinant IFN‐γ together with TNF‐α to the macrophage cultures, but neither alone was sufficient to induce NO production by the macrophages. Our present data indicate that TNF‐α produced by PPD‐stimulated macrophages and IFN‐γ produced by cell‐cell interaction of BCG‐immune T cells and antigen‐engulfed macrophages together activate the macrophages to produce NO.