Leukocyte migration inhibition of tumor antigen and purified protein derivative reactivity in guinea pigs sensitized to line 10 hepatocarcinoma and BCG.

Agarose microdroplet leukocyte migration inhibition (LMI) assays were performed to measure reactivity against line 10 hepatocarcinoma antigens and purified protein derivative (PPD) with the use of peripheral blood leukocytes from line 10 and/or BCG-sensitized syngeneic guinea pigs. The assay was quite sensitive and detected leukocyte migration inhibition with concentrations as low as 12.6 ng protein/ml of the crude sonicate of the line 10 tumor and 0.1 pg PPD. Specificity was shown by lack of reactivity in leukocytes of line 10 and/or BCG-sensitized animals with antigen preparations of L2C leukemia cells or normal syngeneic liver. Furthermore, leukocytes from normal control guinea pigs failed to react with any antigen. The results also suggested antigen cross-reactivity between line 10 tumor and BCG. Leukocytes from guinea pigs sensitized to only BCG became LMI reactive to the line 10 sonicate as well as PPD. No reactivity was observed with leukocytes of the animals in simultaneous tests with a sonicate of guinea pig L2C leukemia cells. The results demonstrated the usefulness of this microassay in detection of LMI reactivity with low antigen concentrations and small volumes of whole blood.