Final answer:
The incorrect statement about B-1 cells is that they express CD25 on their surface. B-1 cells have less N nucleotide diversity in their VDJ junctions and do not express CD25; this marker is more pertinent to T cells.
Step-by-step explanation:
The incorrect statement regarding B-1 cells is that they express CD25 on their surface. B-1 cells are a subset of B cells that are indeed characterized by their ability to exhibit polyspecificity (a), and they do arise during fetal development (b), contributing to the early immune response. They are known for less N nucleotide diversity at their VDJ junctions compared to conventional B cells due to their production mainly in the fetal liver, where the terminal deoxynucleotidyl transferase enzyme is less active (d). However, the expression of CD25, which is the alpha chain of the IL-2 receptor, is primarily associated with the regulation of T cells, not with B-1 cells. B-1 cells differ from conventional B-2 cells in several ways, including their locations, functions, and developmental origin.
In reviewing this question, it is essential to note that B-1 cells are part of the adaptive immune system and mature in the fetal liver, having unique characteristics that distinguish them from conventional B-2 cells, which mature in the bone marrow.