Relationship of Pregnancy-Associated Alpha2-Glycoprotein (alpha2PAG) to Peripheral Blood Leucocytes

Abstract

The high molecular weight plasma glycoprotein pregnancy-associated alpha₂-glycoprotein (α₂-PAG) can be demonstrated on the surface of blood leucocytes and is synthesized by oestrogen-stimulated cells in culture. By the use of an indirect immunofluorescence technique, pretreatment of leucocytes with anli-α₂-PAG IgG revealed α₂-PAG on C3 rosette-forming cells and monocytes but not on E rosettes. Lymphocytes treated with anti-α₂-PAG showed markedly diminished ability to form Fc rosettes. A percentage ranging from 15% to 20% of leucocytes from normal adults of both sexes, pregnant and oestrogen-treated females were positive for α₂-PAG but no obvious correlation was observed between the incidence of α-PAG bearing cells and plasma levels of the protein.