α1-Acid Glycoprotein Possesses in Vitro Pro- and Antiinflammatory Activities

We studied the effects of α1-acid glycoprotein on tumor necrosis factor-α (TNF-α) and interleukin-10 (IL-10) production and lymphocyte response to phytohemagglutinin in cultured peripheral blood mononuclear leukocytes from 6 healthy donors. We observed 2 opposite responses to α1-acid glycoprotein: first, stimulation of TNF-α and IL-10 production and inhibition of lymphocyte proliferation, and second, suppression of cytokine production and stimulation of lymphocyte proliferation. In cell cultures isolated from 4 of 6 donors, the TNF-α/IL-10 ratio remained unchanged after addition of native α1-acid glycoprotein, but some fractions isolated by chromatography on concanavalin A-Sepharose changed this parameter. These changes were most pronounced after treatment with fraction C enriched with molecules with incomplete (biantennary) carbohydrate chains. The mechanisms of α1-acid glycoprotein-induced effects on peripheral blood mononuclear leukocytes are discussed.