Immunosuppressive macrophages induced in Mycobacterium avium complex infection induced in mice
Tomioka, H.; Saito, H.
Kekkaku 67(1): 47-54
1992
ISSN/ISBN: 0022-9776 PMID: 1542208 Document Number: 401309
Profiles of generation and characteristic of splenic macrophages (M phi s), which suppress the ConA mitogenic response of splenic T cells, induced in mice during the course of Mycobacterium avium complex infections were investigated. In MAC-infected mice, reduction of ConA mitogenesis of spleen cells (SPCs) was seen after week 2 and the reduced state thereafter durated as long as at least for 8 weeks. Splenic M phi s with a potent suppressive activity against SPC mitogenesis were transiently induced around 2 weeks after infection. Splenic M phi s of BALB/c (MAC-susceptible) mice had similar but somewhat weaker suppressor activity, as compared to those of CBA/JN (MAC-resistant) mice. The suppressor activity of BALB/c M phi s durated much longer than did CBA/JN M phi s. MAC-induced splenic M phi s were markedly elevated in chemiluminescence and this coincided with increase in immunosuppressive activity. These M phi s inhibited the generation of IL-2-reactive T cell populations in response to ConA-signals, without showing any inhibitory effect against IL-2 producing ability of target T cells. Because immunosuppressive M phi s having the same characteristics were also induced in BALB/c athymic nude mice, thereby indicating that mature T cells are not prerequisite for induction of the present suppressor M phi s in MAC-infected host mice. Prostaglandins (PGs), nitric oxide radical (NO.) and free long chain fatty acids are thought to play certain role in the expression of suppressor action of MAC-induced M phi s, because of the following reasons.