Effector lymphocyte response to homologous tumor antigens in various stages of malignant disease as monitored by leukocyte adherence inhibition - cell mediated immunity (LAI-CMI)

Leukocyte adherence inhibition-cell mediated immunity (LAI-CMI) studies were performed on leukocytes obtained from patients with various stages of breast cancer, colon carcinoma and lung cancer in order to monitor cell mediated immunity during tumor progression. In the presence of autologous serum, all patients with localized tumors showed positive LAI-CMI indexes (> 20%), while significant reduction of homologous tumor antigen recognition as measured by the LAI-CMI responses was observed in nearly all patients with Stage IV breast cancer, Duke C colon cancer and Stage III lung cancer. On substituting autologous serum with normal AB serum, leukocytes from patients with large tumor burdens responded to homologous tumor antigens. These results indicate the existence of organ-specific serum factor(s) which may mask the receptor sites on effector cells for tumor recognition. Patients with such serum blocking factor(s) showed significant increase of IgG immune complexes IgM, IgA and alpha-2-macroglobulins. Application of a protein A affinity column purification resulted in a major reduction of IgG and other immune globulins but not of alpha-2-macroglobulin. The blocking effects of autologous serum, however, were not completely abrogated by fitration on the protein A column, thus suggesting that SBF may be heterogeneous in nature and may occur in other serum protein fractions beside the immune globulins.