Clin. exp. Immunol. (1992) 87, 279-286
Enhancement of the antigen-presenting function of monocytes by cholesterol: possible relevance to inflammatory mechanisms in extrinsic allergic alveolitis and atherosclerosis D. A. HUGHES, P. J. TOWNSEND & P. L. HASLAM Cell Biology Group, Department of Cardiothoracic Surgery, National Heart and Lung Institute, London, UK
(Acceptedfor publication 27 September 1991)
SUMMARY Extrinsic allergic alveolitis (EAA) (synonym: hypersensitivity pneumonitis) is a hypersensitivity lung disease characterized by lymphocytic infiltrates in the pulmonary interstitial tissues. We have previously reported that the numbers of lymphocytes in bronchoalveolar lavage (BAL) samples in this disease correlate with levels ofcholesterol and neutral lipid-laden 'foamy' macrophages. We have also reported that the macrophages express an increased density of MHC class II antigens (in particular HLA-DQ) which are known to be essential for antigen recognition by T lymphocytes. The aim of the present study was to explore whether cholesterol is capable of enhancing the antigenpresenting function of mononuclear phagocytes by modulating the expression of HLA-D region products. Incubation of purified monocytes from healthy volunteers with cholesterol in serum-free medium induced a significant increase in both the percentages of monocytes expressing HLA-DQ (P < 0 02) and in the intensity of expression of the three HLA-D sub-region products, HLA-DQ, -DP and -DR (P
Enhancement of the antigen-presenting function of monocytes by cholesterol: possible relevance to inflammatory mechanisms in extrinsic allergic alveolitis and atherosclerosis D. A. HUGHES, P. J. TOWNSEND & P. L. HASLAM Cell Biology Group, Department of Cardiothoracic Surgery, National Heart and Lung Institute, London, UK
(Acceptedfor publication 27 September 1991)
SUMMARY Extrinsic allergic alveolitis (EAA) (synonym: hypersensitivity pneumonitis) is a hypersensitivity lung disease characterized by lymphocytic infiltrates in the pulmonary interstitial tissues. We have previously reported that the numbers of lymphocytes in bronchoalveolar lavage (BAL) samples in this disease correlate with levels ofcholesterol and neutral lipid-laden 'foamy' macrophages. We have also reported that the macrophages express an increased density of MHC class II antigens (in particular HLA-DQ) which are known to be essential for antigen recognition by T lymphocytes. The aim of the present study was to explore whether cholesterol is capable of enhancing the antigenpresenting function of mononuclear phagocytes by modulating the expression of HLA-D region products. Incubation of purified monocytes from healthy volunteers with cholesterol in serum-free medium induced a significant increase in both the percentages of monocytes expressing HLA-DQ (P < 0 02) and in the intensity of expression of the three HLA-D sub-region products, HLA-DQ, -DP and -DR (P
