Different efficacy of various blocking reagents to eliminate interferences by human antimouse antibodies with a two-site immunoassay
Clin.Biochem., 29 (2):
145-148 (1996)Abstract
OBJECTIVE: The efficacy of three reagents to eliminate interferences with the cancer antigen 125 (CA-125) assay Enzymun CA-125 II by human antimouse antibodies (HAMA) formed by patients after injection of the murine anti-CA-125 antibody OC125 is compared. METHODS: Apparent CA-125 concentrations of 14 serum samples obtained from 6 patients after multiple injections of 1 mg radiolabeled OC125 F(ab')2 fragments were measured with the Enzymun CA-125 II before and after preincubation, either with nonspecific mouse IgG, with the polymerized mouse IgG MAK-33, or with the commercially available HAMA-blocking reagent IIR. RESULTS: In all samples with HAMA concentrations ranging from 341 to 46900 microg/L, false-positive CA-125 values were measured with the Enzymun CA-125 II, which could be reduced by preincubation with the HAMA-blocking reagents. However, although after preincubation with 2 g/L IIR for all samples the CA-125 concentrations measured were reduced to values within the normal range