A Level Biology Practice Exam

Which of the following statements about T lymphocytes is correct?

1. They mature in the thymus but do not fight infections

2. They directly produce antibodies

3. They stimulate B lymphocytes and kill pathogens

4. They can only function in isolation

The correct answer is: They stimulate B lymphocytes and kill pathogens

T lymphocytes play a crucial role in the adaptive immune response. They mature in the thymus, where they undergo selection processes to ensure that they can recognize antigens presented by other cells while remaining tolerant to self-antigens. This immunological training prepares them to contribute to the immune system effectively. The statement about T lymphocytes stimulating B lymphocytes and killing pathogens highlights the two primary functions of different types of T cells. Helper T cells activate B lymphocytes, leading them to produce antibodies. Meanwhile, cytotoxic T cells directly kill infected or cancerous cells by recognizing specific antigens presented by these cells. This understanding distinguishes T cell functionality from other aspects of the immune response, such as the direct production of antibodies, which is exclusively the role of B lymphocytes. T lymphocytes do not function effectively in isolation; they work in conjunction with other immune cells, illustrating the collaborative nature of the immune system. Therefore, the correct statement accurately captures the multifaceted role of T lymphocytes in both stimulating B cells and combating pathogens.