Corynebacterium parvum: antibodies measured with the enzyme-linked immunosorbent assay (ELISA) in normal human sera and sera from cancer patients undergoing treatment.

An enzyme-linked immunosorbent assay (ELISA) was developed to monitor the antibody response to Corynebacterium parvum during cancer immunotherapy. Firstly, in sera from 176 clinically healthy individuals not treated with C. parvum, elevated ELISA extinction values were observed from the age of 11 years onwards for both sexes; these high values were probably due to preexisting antibodies to C. parvum or related organisms. Consequently, in order to evaluate C. parvum antibody levels after treatment it was essential to compare post- with pre-treatment sera. Next, a series of sera from 20 male patients with inoperable squamous cell carcinoma of the bronchus were tested. They originated from three different groups. The first group received both chemotherapy (cyclophosphamide) and immunotherapy (C. parvum), the second group cyclophosphamide alone and the third group neither of these agents. Compared to pre-treatment values, an increase in extinction values was already observed as from day 12 of C. parvum treatment; cyclophosphamide did not influence the extinction values. Antibody production per se did not seem to be correlated with an anti-tumour effect. The sensitivity of ELISA was similar to a previously described latex agglutination test.