HYBRIDOMA SCREENING USING AN AMPLIFIED FLUORESCENCE MICROASSAY TO QUANTIFY IMMUNOGLOBULIN CONCENTRATION

The early identification of antibody-secreting hybridomas significantl y reduces the time and resources devoted to unproductive colonies, To quantify the immunoglobulin concentration in hybridoma supernatants wi thin 2 weeks of fusion, we used immunomagnetic microspheres to capture immunoglobulin in the hybridoma culture supernatant, The captured imm unoglobulin was detected using a goat anti-mouse second antibody liked to beta-galactosidase. With data transformation to correct for the no nlinear accumulation of the fluorescent reaction product, the enzymati c hydrolysis of fluorescein digalactoside permitted the reliable detec tion of less than 10 pg of immunoglobulin per milliliter, To determine the value of quantifying immunoglobulin concentration within 2 weeks of fusion, the amplified fluorescence microassay was applied to the ev aluation of 3 consecutive fusions and more than 1200 growing hybridoma colonies, Using antibody concentrations greater than 10 ng/ml as a th reshold for routine subculture, the selection of hybridoma colonies ba sed on antibody secretion was threefold more efficient than selection based on colony growth alone, These results suggest the utility of the early determination of immunoglobulin concentration in the selection of hybridoma colonies.