SIALOPROTEINEMIA - LACK OF CORRELATION WITH INHIBITION OF INVITRO LYMPHOBLASTOSIS INDUCED BY PHYTOHEMAGGLUTININ OR ALLOANTIGEN

Abstract

Elevation of serum bound sialic acid concentration in different disease states fails to correlate significantly with suppressive serum actions in mixed allogeneic lymphocyte cultures or phytohemagglutinin cultures. Heat decomplemented serum from patients with abnormal levels of bound sialic acid was added to parallel cultures containing similar blood lymphocyte populations derived from normal humans. Wide fluctuations of the rate of incorporation of 3H-thymidine into nucleoprotein indicated presence of suppressive elements other than sialoprotein in the added serum components. Serum with rising sialyl concentration derived from patients with cancer showed slight tendency to augment mixed lymphocyte and phytohemagglutinin responses. The previously documented nonspecific suppressive action of serum sialoprotein on human host lymphoblastic response to [Vibrio cholerae] neuraminidase treated cancer cells represents a mechanism unique to that culture system rather than a manifestation of a general immunoregulatory function of serum sialoprotein.