Final answer:
B cell epitopes are 8-22 amino acids in length and are found externally on antigens. They are specifically recognized by B-cell receptors, which bind to these epitopes through their Fab antigen-binding regions to initiate immune response.
Step-by-step explanation:
B cell epitopes are typically 8-22 amino acids long and are located on the external part of antigens. These epitopes are the specific parts of antigens that are recognized and bound by the antigen-binding sites of B-cell receptors (BCRs).
BCRs are membrane-bound monomeric forms of IgD and IgM that bind specific antigen epitopes with their Fab antigen-binding regions. The diversity in the BCRs is due to the genetic rearrangement of V, D, and J segments, allowing a vast array of antigen specificities to be recognized by the immune system. B cells are integral to the humoral arm of the immune response, with each B cell producing upwards of 100,000 BCRs, each with identical epitope specificity, allowing them to bind to the external regions of pathogens and initiate the activation process of the adaptive immune response.