Final answer:
Mature B-1 cells show limited diversity in their V region due to less genetic rearrangement compared to conventional B-2 cells. Their V region diversity is restricted, which reflects their role in innate-like immune responses rather than the extensive antigen recognition typical of B-2 cells.
Step-by-step explanation:
Mature B-1 cells show limited diversity in their V region. This is because B-1 cells are a specialized subset of B cells that exhibit less V(D)J recombination compared to conventional B-2 cells. The variable region (V region) of B-1 cell receptors is less diverse due to this reduced genetic rearrangement. During the maturation process of germ-line B cells, an enzyme called DNA recombinase randomly excises V and J segments from the light chain gene. The DNA is then spliced at the mRNA level, which results in further gene rearrangement. This process can create over 106 potential VJ combinations, but despite this large number, B-1 cells tend to utilize a more limited subset of V regions, which leads to their reduced diversity in antigen recognition.
The V, D, and J gene segments contribute to the genetic diversity necessary for the production of millions of receptors, each with unique antigen-binding sites. This diversity is crucial for the immune system to recognize and eliminate a vast array of antigens. However, B-1 cells, which are thought to play a role in innate-like immune responses, have a restricted repertoire, which is adequate for their specialized function but is not as extensive as that of B-2 cells.