Final answer:
The incorrectly matched counterpart in the development of B cells compared to T cells is Pax-5: FoxP3, as Pax-5 is crucial for B cell development, and FoxP3 is associated with regulatory T cells, not naive T cell development.
Step-by-step explanation:
The correctly matched counterparts in development of B cells and T cells are VpreBλ5 to pTα and Igα/Igβ to CD3, since these pairs represent analogous components between B cells and T cells in their development. However, the incorrectly matched counterpart from the options provided is Pax-5: FoxP3. Pax-5 is a transcription factor involved in B cell development, whereas FoxP3 is a transcription factor most closely associated with the regulation of regulatory T cells (Tregs), not a direct counterpart in the development of naive T cells. In B cells, light-chain gene rearrangements produce multiple κ and λ light chains, while in T cells, multiple α-chain gene rearrangements contribute to TCR diversity, correctly reflecting the counterparts in antigen receptor gene rearrangement processes.