Accessory Cell Function of Dendritic Cells from Lymph Nodes containing <i>Mycobacterium leprae</i> Induced Granulomas

Abstract

Dendritic cells were enriched from guinea pig auricular lymph nodes containing Mycobacterium leprae induced granulomas by immunomagnetic depletion of other cells. These cells were strongly positive for major histocompatibility complex class II antigens and labelled with an antidendritic cell monoclonal antibody, but not with an antimacrophage antibody. Interdigitating dendritic cells were identified in the granulomatous lymph node by staining with the antidendritic cell antibody and by transmission electron microscopy. When cultured in vitro with purified T lymphocytes, these cells acted as accessory cells for both purified protein derivative and concanavalin A induced proliferation. Although previous studies have shown that macrophages from these lymph nodes do not act as accessory cells, the present results indicate that dendritic cells from M. leprae granuloma containing lymph nodes may act as antigen-presenting cells.

Ovine mononuclear phagocytes in situ: identification by monoclonal antibodies and involvement in experimental pyogranulomas

“…The importance of macrophage surrounding a suppurative center in such lesions agrees wi results of earlier studies (14,16,19,33,52) and emphasize the denominations of pyogranuloma or suppurative granu Joma used to designate these lesions (21,38). Obviously, thi does not exclude the participation of other cells such eosinophils stained by MAb OMl, which have been de scribed in granulomas induced by parasites (22), or dendriti cells (41,55).…”

Mycobacterium lepraeInfection in Monocyte-Derived Dendritic Cells and Its Influence on Antigen-Presenting Function

“…Similar results were observed in this study, as DCs were quite efficient in the induction of T-cell responses against M. avium and BCG. In leprosy, although CD1 ϩ CD83 ϩ monocyte-derived DCs have been found in a localized tuberculoid-form leprosy lesion, in which cellular immune reactions are observed (39,50), the role of DCs against M. leprae infection has not been fully clarified.…”

Expression of B7-1 costimulatory molecules in patients with multibacillary leprosy and reactional states

“…Expression of such costimulatory molecules by DCs plays an important role in the generation of an efficient T‐cell response 9 . In this context, the ability of DCs to act as potent APCs for induction of T‐cell response to antigens is widely described both in vitro 4,18–20 and in vivo 21,22 . Based on these observations, the lack of B7‐1 expression in lesions from patients with MB‐L cannot be explained by an intrinsic defect of the B7‐1 system of the patients studied.…”