Question

Cell-mediated immunity in the human body is carried out by

• A. Erythrocytes
• B. T-lymphocytes
• C. B-lymhocytes
• D. Thrombocytes

Answer 1

The Correct Option is B

Cell-mediated immunity is an essential part of the immune response that involves the activation of certain immune cells to fight off pathogens, particularly viruses and cancer cells. Let's break down the question and explain why T-lymphocytes are the correct answer:

1. Understanding Cell-Mediated Immunity:
   • Cell-mediated immunity is primarily concerned with the defense against pathogens that live inside cells, such as viruses and some types of bacteria.
   • T-lymphocytes, or T-cells, are the key players in this type of immunity. They do not produce antibodies; instead, they act directly against infected cells and pathogens.
2. Role of T-Lymphocytes:
   • T-lymphocytes originate from bone marrow and mature in the thymus, which is why they are called "T" cells.
   • They recognize infected cells via receptors on their surface and directly kill them or help coordinate the immune response.
   • Two important types of T-cells involved in cell-mediated immunity are cytotoxic T-cells (which kill infected cells) and helper T-cells (which activate other immune cells).
3. Why Other Options Are Incorrect:
   • Erythrocytes: These are red blood cells responsible for carrying oxygen, not immunity.
   • B-Lymphocytes: These cells are involved in humoral immunity and produce antibodies, not directly involved in cell-mediated immunity.
   • Thrombocytes: Also known as platelets, they are involved in blood clotting, not immunity.
4. Conclusion: Given that the primary function of cell-mediated immunity is carried out by T-lymphocytes, they are the correct choice for this question. They ensure the body can respond to intracellular threats effectively.