Binding of alpha 2HS glycoprotein in peripheral blood monocytes.

The binding of 125I-alpha 2HS glycoprotein to peripheral blood monocytes was investigated at 4 degrees C. Equilibrium was attained after 60 min incubation with little internalization of radiolabeled protein. Binding was partially dependent on Ca++. Scatchard plot analysis revealed a dissociation constant of 10(-4) M with 10(6) sites/cell. The low binding affinity between alpha 2HS glycoprotein and peripheral blood monocytes may be offset by the relatively high serum concentration of this protein in the expression of its phagocytic enhancing properties.