Inhibition of antibody-dependent cellular cytotoxicity (ADCC) by normal and pathological sera from patients with advanced lung cancer.

An improved ADCC assay for the detection of cancer-associated serum blocking factors is described. Inhibition of ADCC by sera was performed without preincubation and washing of effector cells. Effects of individual susceptibility of normal effector cells to serum inhibitors and of the background inhibition by normal sera were also avoided. Based on their inhibitory effect on ADCC, normal and tumour sera from lung cancer patients could be distinguished with 81.4 to 100% accuracy, according to effector cell donors and to concentrations of the sera tested.