Effect of isolation techniques, in vitro culture and IFN gamma treatment on the constitutive expression of MHC Class I and Class II molecules on goatneutrophils

Previous studies on the ability of human neutrophils to synthesize cytokine s and express MHC Class I and inducible Class II molecules have suggested a possible role of these cells as accessory or antigen presenting cells (APC ). There is no information available to date concerning this aspect in rumi nants. Therefore, as the first step of these investigations, we have studie d the cell surface expression of MHC molecules on goat neutrophils. We show that goat neutrophils can be distinguished from eosinophils with monoclona l antibody (MoAb) ILA-24 which recognizes cattle monocytes and neutrophils. Goat neutrophils constitutively express MHC Class II molecules. However, c ell surface expression of MHC Class I and Class II molecules is dramaticall y reduced on neutrophils purified by density gradient centrifugation in com parison to neutrophils obtained from whole blood after lysis of erythrocyte s. Also, the level of expression of MHC Class I antigens is seasonal and do nor-dependent and rapidly decreases after in vitro culture despite negligib le necrosis and apoptosis of neutrophils. Although treatment with IFN gamma partially prevents the loss of MHC Class I molecules on neutrophils, it fa ils to induce MHC Class II antigens. Implications of these results for furt her studies on the potential role of neutrophils as APC are discussed. (C) 1999 Elsevier Science B.V. All rights reserved.