High Frequency of Loss of Human Kappa Light Chain Expression in Mouse-Human Heterohybridomas

Abstract

The expression of human immunoglobulin (Ig) chains in human-mouse heterohybridomas was investigated on the days after cell fusion. Heterohybridomas were made by fusion of mediastinal lymphocytes from lung carcinoma patients and murine (BALB/c) myeloma P3U1. Most (more than 76%) of heterohybridomas easily lost the light chain rather than the heavy chain expression in the early stages after cell fusion. Frequency of loss of κ-chain expression was predominant, whereas the expression of heavy chain and λ-chain was rather stable in comparison with that of κ-chain. These were also confirmed at the clonal level, demonstrating that only λ-chain but not κ-chain producers were successfully enriched. In fact some heterohybridomas producing human Ig of λ-chain type established were found to be quite stable for more than 2 years without any recloning procedures.