I am a beginner to clone the monoclonal antibody. The sequence analysis results showed that all the clones of kappa chain Variabe region were the aberrant Vk mRNA which could not be translated into a fully functional IgG protein due to the presence of a four necleotide deletion at the VJ joining site. I searched in the PubMed and tried several methods, but it did not work. Because the RNA available is limited, I need a good method to clone the functional kappa chain. Could anyone give me some advice? Thanks a lot.