Arming of Normal Leukocytes with Sera from Patients with Adenocarcinoma of the Prostate

A tumor-associated antigen-induced leukocyte adherence inhibition assay was used to evaluate the effect of serum from patients with adenocarcinoma of the prostate on the antitumor reactivity of normal leukocytes. Peripheral blood leukocytes from 53 normal (control) subjects were armed with serum from 22 patients with localized (Stage A) and metastatic (Stage D) prostatic cancer and reacted with allogenic extract of malignant prostate as specific tumor-associated antigen. Leukocytes pretreated with serum from patients with Stage A cancer show significantly stronger responses to malignant prostate than do those pretreated with serum from patients with Stage D cancer, which induced little or no response. This may be attributed to an “arming factor” present in the sera of patients with an initial stage of prostatic cancer which appears to be capable of sensitizing normal leukocytes and making them specifically reactive to tumor extract. The specificity of arming with individual and pooled patient's sera was delineated by the use of extracts from other genitourinary tumors.