A comparative analysis of the phenotypic characteristics of available fusion partners for the construction of human hybridomas.

Of several human fusion partners available for the production of monoclonal antibodies, only SKO-007 and RPMI 8226 have phenotypic features characteristic for myeloma cells. Cells from both lines exhibited abundant rough endoplasmic reticulum (RER) with a prominent Golgi apparatus, few free ribosomes, condensed nuclear chromatin, and absence of the Epstein-Barr virus determined nuclear antigen (EBNA). However, following prolonged passage of these lines, the amount of immunoglobulin (Ig) production has declined. The other cell lines, GM 1500 6TG-A11, KR-4, B6, HS-Sultan, and Raji possessed the phenotypic characteristics of B-lymphoblastoid cell lines (LCLs) and B-lymphomas including surface Ig expression, sparse RER, free polyribosomes, a poorly developed Golgi apparatus and strong EBNA expression. Accordingly, they secreted little (nanograms) or no Ig. However, hybrids constructed with two LCLs secrete very large amounts of Ig despite their expressed morphologic similarity to the parental lines. These data indicate that morphology can still be used as an important consideration in choosing a human fusion partner but other parameters such as fusion frequency, cloning efficiencies, and growth rates may be equally important.