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Mechanism of UVB‐Induced Suppression of the Immune Response to Mycobacterium bovis Bacillus Calmette‐Guerin: Role of Cytokines on Macrophage Function
Author(s) -
Jeevan Amminikutty,
Ullrich Stephen E.,
Gracia Maria De,
Shah Rupa,
Sun Yan
Publication year - 1996
Publication title -
photochemistry and photobiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.818
H-Index - 131
eISSN - 1751-1097
pISSN - 0031-8655
DOI - 10.1111/j.1751-1097.1996.tb02455.x
Subject(s) - immune system , tumor necrosis factor alpha , immunology , microbiology and biotechnology , cytokine , biology , macrophage , mycobacterium bovis , antibody , chemistry , in vitro , mycobacterium tuberculosis , medicine , pathology , tuberculosis , biochemistry
Abstract Previously we demonstrated that treatment of mice with either UVB radiation or supernatants derived from UVB‐irradiated PAM 212 keratinocytes decreased the induction of the delayed‐type hypersensitivity (DTH) response to Mycobacterium bovis bacillus Calmette‐Guerin (BCG), impaired the clearance of bacteria from their lymphoid organs and also altered macrophage functions. In order to characterize the cytokines involved in these phenomena, UV‐irradiated mice were injected with antibodies to interleukin‐10 (IL‐10), transforming growth factor‐β1 (TGF‐β1), or tumor necrosis factor‐α (TNF‐α). Injection of UVB‐irradiated mice with anti‐IL‐10 immediately after UV irradiation restored the DTH response and reversed the UV‐induced inhibition of bacterial clearance. Injection of UV‐irradiated mice with anti‐TGF‐β only partially restored the DTH response although it allowed a better clearance of BCG than injection of mice with the control antibody. In contrast, injection of anti‐TNF‐α did not affect the UVB‐induced suppression of DTH or impaired bacterial clearance. Similarly, the ability of macrophages to phagocytose BCG and kill the intracellular organisms was restored to almost normal levels after injecting UV‐irradiated mice with antibodies specific for IL‐10 or TGF‐β. Injection of mice with either recombinant IL‐10 or TGF‐β mimicked the effect of whole‐body UV irradiation on immune function. These results suggest that IL‐10 has a major role in UV‐induced suppression of both DTH to BCG and impairment in the clearance of bacteria and that TGF‐β has a more significant role in blocking bacterial clearance. Furthermore, these cytokines seem to modulate immune responses by altering macrophage functions in UVB‐irradiated mice.