IL-32 expression in the airway epithelial cells of patients with Mycobacterium avium complex lung disease.
Lung disease due to Mycobacterium avium complex (MAC) organisms is increasing. A greater understanding of the host immune response to MAC organisms will provide a foundation to develop novel therapies for these recalcitrant infections. IL-32 is a newly described pro-inflammatory cytokine that enhances host immunity against various microbial pathogens. Cytokines that induce IL-32 such as interferon-gamma, IL-18, IL-12 and tumor necrosis factor-alpha are of considerable importance to mycobacterial immunity. We performed immunohistochemistry and morphometric analysis to quantify IL-32 expression in the lungs of 11 patients with MAC lung disease and 10 controls with normal lung tissues. After normalizing for basement membrane length, there was a profound increase in IL-32 expression in the airway epithelial cells of the MAC-infected lungs compared with controls. Following normalization for alveolar surface area, there was a trend toward increased IL-32 expression in type II alveolar cells and alveolar macrophages in the lungs of MAC patients. Human airway epithelial cells (BEAS-2B) infected with M. avium produced IL-32 by a nuclear factor-kappa B-dependent mechanism. In both BEAS-2B cells and human monocyte-derived macrophages, exogenous IL-32γ significantly reduced the growth of intracellular M. avium. This finding was corroborated by an increase in the number of intracellular M. avium recovered from THP-1 monocytes silenced for endogenous IL-32 expression. The anti-mycobacterial effect of IL-32 may be due, in part, to increased apoptosis of infected cells. These findings indicate that IL-32 facilitates host defense against MAC organisms but may also contribute to the airway inflammation associated with MAC pulmonary disease.
Department of Medicine, Denver Veterans Affairs Medical Center, Denver, CO 80220, USA. baix@njhealth.org
Xiyuan
X
Bai
Alida R
AR
Ovrutsky
Marinka
M
Kartalija
Kathryn
K
Chmura
Amanda
A
Kamali
Jennifer R
JR
Honda
Rebecca E
RE
Oberley-Deegan
Charles A
CA
Dinarello
James D
JD
Crapo
Ling-Yi
LY
Chang
Edward D
ED
Chan
D000368:Aged; D016022:Case-Control Studies; D002478:Cells, Cultured; D004847:Epithelial Cells / Q000187:drug effects / Q000276:immunology* / Q000382:microbiology; D005260:Female; D015870:Gene Expression; D006801:Humans; D007150:Immunohistochemistry; D007371:Interferon-gamma / Q000276:immunology; D018664:Interleukin-12 / Q000276:immunology; D020382:Interleukin-18 / Q000276:immunology; D007378:Interleukins / Q000235:genetics / Q000276:immunology* / Q000494:pharmacology; D008264:Macrophages / Q000187:drug effects / Q000276:immunology* / Q000382:microbiology; D016676:Macrophages, Alveolar / Q000187:drug effects / Q000276:immunology* / Q000382:microbiology; D008875:Middle Aged; D009000:Monocytes / Q000187:drug effects / Q000276:immunology* / Q000382:microbiology; D015269:Mycobacterium avium Complex / Q000187:drug effects / Q000254:growth & development / Q000276:immunology*; D015270:Mycobacterium avium-intracellulare Infection / Q000188:drug therapy / Q000276:immunology* / Q000378:metabolism / Q000382:microbiology; D016328:NF-kappa B / Q000276:immunology; D012137:Respiratory System / Q000187:drug effects / Q000276:immunology* / Q000378:metabolism / Q000382:microbiology; D014409:Tumor Necrosis Factor-alpha / Q000276:immunology; D014481:United States
C496971:IL32 protein, human; D020382:Interleukin-18; D007378:Interleukins; D016328:NF-kappa B; D014409:Tumor Necrosis Factor-alpha; D018664:Interleukin-12; D007371:Interferon-gamma