Detection of a retrovirus-related glycoprotein in immune complexes from patients with hematopoietic disorders.

Human sera from normal and leukemic individuals were found to contain various amounts of an antigen with determinants related to p15E and reverse transcriptase of retroviruses. Using a specific monoclonal antibody and the immuno-affinity purified antigen, we surveyed a series of sera and plasmas from normal individuals and hematological patients by competition radioimmunoassays and binding assays directed against this specific protein. It was detected in all the samples at various levels. The level of this 74-kd glycoprotein appeared to be related to a stimulation of the hematopoietic system. No free antibodies were found that could recognized the labelled purified antigen. Only immune complexes prepared from the blood of some hematological patients contained the specific antigen, but complexes prepared from the blood of normal individuals did not.