Question

Helper T-lymphocytes perform following functions EXCEPT ______.

• A. Stimulation of B-lymphocytes
• B. Proliferation of other T-cells
• C. Attraction of macrophages
• D. Secretion of cell killing substances like perforins

Hint:

Helper T-cells regulate immunity, while cytotoxic T-cells kill infected cells using perforins.

Answer 1

The Correct Option is D

Step 1: Understanding helper T-lymphocytes.
Helper T-cells (CD4\textsuperscript{+}) play a central role in regulating immune responses. They do not directly kill infected or abnormal cells but coordinate immune activities through cytokine secretion.
Step 2: Functions of helper T-cells.
Helper T-cells stimulate B-lymphocytes to produce antibodies.
They promote proliferation and activation of other T-cells.
They secrete cytokines that attract and activate macrophages.
Step 3: Identifying the exception.
Secretion of cell-killing substances like perforins is a function of cytotoxic T-lymphocytes (CD8\textsuperscript{+}), not helper T-cells.
Step 4: Conclusion.
Helper T-lymphocytes do not secrete perforins; hence option (D) is correct.