Final answer:
T-cells only recognize peptide antigens presented on MHC molecules by APCs, while B-cells can recognize all bio-organic molecules directly and are responsible for producing antibodies.
Step-by-step explanation:
The correct answer to the question is a. T-cells, B-cells. T-cells only recognize peptide antigens presented on MHC (Major Histocompatibility Complex) molecules by antigen-presenting cells (APCs), while B-cells can recognize all four bio-organic molecules, including proteins, carbohydrates, lipids, and nucleic acids. T-cells require antigen processing before recognition, whereas B-cells can bind with intact antigens directly without the need for MHC involvement.
B-cells differentiate in the bone marrow and are capable of recognizing a vast array of antigenic structures directly due to the diversity of their receptors. In contrast, T-cells recognize antigens with highly specific T-cell receptors and are educated in the thymus to only bind foreign antigens presented by MHC molecules, which is essential for their role in immune response.
Both T and B cells are crucial for the adaptive immune response, recognizing specific antigens via their receptors; however, the mechanisms of antigen recognition between these two cell types differ significantly.