Serum la Levels During Tumor Growth in Mice and Humans

Abstract

Antigen stimulation in mice such as occurs with the rejection of an allogeneic tumor graft caused a substantial rise in serum glycolipid la levels. However, mice bearing a measurable syngeneic tumor had no detectable la antigens in their sera; this observation was made in several different strains of inbred mice with 5 different tumors. In each instance the serum la level fell as the tumor grew progressively, reached zero at about the time the tumor was visible, and remained at this zero level until the mouse died. Similar results were found in humans: Tumor-bearing patients had markedly suppressed serum la levels. The mechanism of the fall in serum la glycolipid levels is not known, but the measurement of the serum la glycolipid content appears to reflect the level of activation of the immune system, and the suppression of serum glycolipid la levels found in tumorbearing mice and patients may have important clinical implications.