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Question: Which of the following are not a type of T-lymphocyte? A. Helper B. Suppressor C. Cytotoxic ...

Which of the following are not a type of T-lymphocyte?
A. Helper
B. Suppressor
C. Cytotoxic
D. Repressor

Explanation

Solution

Firstly we need to know about the T-lymphocyte. T-lymphocytes are a very important part of our immune system. These cells develop from stem cells in the bone marrow. They help to protect our body from infections and may help fight cancer as well. They are also called T-cell and Thymocyte. A blood stem cell goes through a number of steps to become a RBC or a platelet or a WBC.

Complete answer:
Repressor is not a type of T-lymphocyte. A repressor is a type of protein that has a negative consequence on gene expression.
So, Option D ‘Repressor’ is the correct answer.

Option A – Helper: A type of immune cell that rouses killer T cells, B cells and macrophages to make immune answers. A helper T cell is a type of WBC and a type of lymphocyte. They are also called CD-positive T lymphocytes.
So, Helper is the name of T-lymphocyte. Thus the Option A ‘Helper’ is not the correct answer.
Option B – Suppressor: A type of immune cell that blocks the activities of some other types of lymphocytes to keep the immune system from becoming over-active. In the treatment of cancer the Suppressor T cells are being studied.
So, Suppressor is the name of T-lymphocyte. Thus the Option B ‘Suppressor’ is not the correct answer.
Option C – Cytotoxic: A cytotoxic T cell is a T lymphocyte or a type of WBC that kills cancer cells or cells that are infected (mainly with viruses) or cells that are damaged in other ways.
So, Cytotoxic is the name of T-lymphocyte. Thus the Option C ‘Cytotoxic’ is not the correct answer.

Note:
The cytotoxic T cells are also known as TC or cytotoxic T lymphocytes or CTL or T-killer cell or cytolytic T cell or CD8+ T-cell or killer T cell.
All T cells originate from haematopoietic stem cells (HSC) which exist in the bone marrow. In some cases the source might be the fatal liver during embryonic development.
T cells can be distinguished from other lymphocytes by the presence of a T-cell receptor (TCR) on their surface.