Isolation of Rare Isotype Switch Variants in Hybridoma Cell Lines Using an Agarose Gel Microdrop-Based Protein Secretion Assay

Abstract

Using gel microdrop (GMD) encapsulation technology and fluorescence-activated cell storing (FACS), we have developed a rapid, sensitive, and reliable method for discriminating and recovering rare isotypic switch variants in hybridoma cell lines. Using the GMD-based IgSwitch^™ assay, a novel approach for isolating subpopulations of IgG-secreting hybridoma cells present at a frequency of ∼1-10 in 10⁶, we successfully isolated spontaneous and in vitro-induced isotypic switch variants in less than half the time required for conventional sublining. The effectiveness and specificity of the assay are demonstrated.