Why are there more antibodies with kappa light chains than lambda light chains?

Question

What will be an ideal response

Answer 1

Germline DNA contains the complete DNA genome of an individual. The first event in converting a pro-B cell with
Germline DNA to a pre-B cell is the rearrangement of DNA on one of the chromosome 14's coding for the
immunoglobulin heavy chain. In the rearrangement, one V gene, one D gene, and one J gene are selected, and
intervening DNA is spliced out. If the rearrangement is productive, the cell becomes a pre-B cell. Pre-B cells
rearrange the DNA coding for the light immunoglobulin chain, and if that rearrangement is productive, then the
cell becomes an immature B cell. To rearrange light chain DNA, the cell first attempts to rearrange kappa chain
DNA on chromosome 2. If the rearrangement on the first chromosome 2 fails, then it is attempted on the second
chromosome 2. If that fails, then the two chromosome 22's coding for lambda light chain are attempted. Thus, since
the first attempt is always for kappa light chain and lambda light chain is never attempted if the kappa
rearrangement is successful, ultimately more antibodies contain kappa light chains.