What are the two types of immunocytes?

• A. T-lymphocytes and E-lymphocytes
• B. B-lymphocytes and plasma cells
• C. B-lymphocytes and T-lymphocytes
• D. Natural killer cells and macrophages

Answer: (C)

The correct answer identifies the two primary types of immunocytes as B-lymphocytes and T-lymphocytes. These cells are critical components of the adaptive immune system. B-lymphocytes are primarily responsible for producing antibodies that bind to antigens, leading to the neutralization or destruction of pathogens. They play a significant role in humoral immunity. T-lymphocytes, on the other hand, are crucial for cell-mediated immunity; they can directly kill infected host cells, activate other immune cells, and regulate immune responses.

In contrast, while plasma cells are indeed related to B-lymphocytes, they are differentiated forms of B cells that produce antibodies rather than the two primary types of immunocytes. Natural killer cells and macrophages, mentioned in another option, belong to the innate immune system and do not represent the same category of adaptive immune cells as B and T-lymphocytes. This differentiation is essential in understanding immune responses and the roles various cells play within those responses.