Final answer:
T lymphocytes and B lymphocytes differ in their antigen recognition and roles in the immune response. T cells require antigen presentation with MHC molecules, whereas B cells can directly bind to intact antigens. B cells are involved in humoral immunity through antibody production, while T cells mediate cellular immunity.
Step-by-step explanation:
The student has inquired about the difference between T lymphocytes and B lymphocytes. T cells primarily bind to antigens that have already been processed and presented by Antigen-Presenting Cells (APCs) in complex with Major Histocompatibility Complex (MHC) molecules. On the other hand, B cells can bind intact antigens directly without the need for processing by APCs, as they themselves can function as APCs. After activation, B cells differentiate into plasma cells that produce antibodies, which are crucial for humoral immunity. Conversely, T cells are primarily involved in cell-mediated immunity, where they may directly attack infected or foreign cells.
Certain bacterial carbohydrates and lipids can directly activate B cells without the need for T cell help. Both B cells and T cells are morphologically similar but differ in the sites where they mature—B cells in the red bone marrow and T cells in the thymus. They also have unique functions in the adaptive immune response. While B cells are responsible for antibody production, T cells are known for their role in directly targeting pathogens and infected cells. Memory cells, which are long-lived forms of B and T cells, also develop after exposure to pathogens to provide a quicker response upon subsequent encounters.
Therefore, when explaining how T lymphocytes and B lymphocytes differ, it is important to note their distinct antigen recognition pathways and their unique roles in the immune response.