This set of Life Sciences Multiple Choice Questions & Answers (MCQs) focuses on “T-Cells”.
1. Which of the tracing is NOT the role of T-cell receptor complex?
a) α and β chain
b) CD3
c) CD19
d) CD40L
View Answer
Explanation: CD19 is a co-receptor of B-cell receptor complex while T-cell receptor complex consists of antigen recognizing α and β chains, expressed on the surface of T-cell in noncovalent association with CD3 molecule. CD40L and CD28 are co-stimulatory molecules.
2. Coreceptor CD3 is used to bind antigen.
a) True
b) False
View Answer
Explanation: CD3 is present with antigen recognizing α and β chain of TCR; these molecules do not bind with antigen instead of transduce signals after the activation.
3. Name the syndrome occurs in children due to deficiency of the thymus.
a) Acromegaly
b) Gigantism
c) Cushing syndrome
d) DiGeorge syndrome
View Answer
Explanation: Thymus is required for the development of T-cells. Children which are born without thymus undergo adverse effects of not having matured T-cells; this syndrome is known as DiGeorge syndrome.
4. Which of the following steps is NOT involved in the activation of T-cell?
a) Double positive cell converts to single positive T-cell
b) Foreign peptide bound to MHC provide signals
c) CD28 of TCR interacts with B7 of APC
d) CD23 has ITAM, which transducer signals
View Answer
Explanation: The conversion of double positive cells to a single positive cell is thymic selection process in which T-cell mature with the interaction of MHC and develops the tolerance to self-antigen.
5. Name the cytokines which act as a T-cell growth factor?
a) IL-3
b) IL-2
c) IL-4
d) IL-5
View Answer
Explanation: Cytokines released by T-helper cells and have several functions like IL-2 act as T-cell growth factor while IL-4 and IL-5 help in B-cell activation, IL-3 involved in hematopoiesis and secreted by both TH1 and TH2 subset of T-helper cell.
6. Cytokinin which acts as a growth factor of B-cell is________
a) IFNγ
b) IL-10
c) IL-13
d) TNFβ
View Answer
Explanation: IL-13 is secreted by TH2 and act as B-cell growth factor while IL-10 inhibits macrophages, while IFNγ and TNFβ secreted by TH1 and used to activate macrophages and inflammatory responses.
7. Mark the correct role of cytosolic T-cells.
a) Help in B-cell activation
b) Produce cytotoxin
c) Proliferate T-cell
d) Kill the target cell
View Answer
Explanation: Cytotoxic T-cell (CTL) once activated it initiate killing of target cells by attaching to it. After interaction with a target cell, it undergoes conjugate formation with the help of calcium. The killing action is performed by cytotoxic substances contained in granules of T-cells.
8. Name the major constituents of cytotoxic T-lymphocyte?
a) Lysozyme
b) Lymph
c) Protein
d) Perforin and granzyme
View Answer
Explanation: Perforin and granzyme are the cytotoxic substances present in granules of CTL. Perforin involves in the formation of pores on the target cell while granzyme performs apoptosis by direct activation of apoptosis.
Sanfoundry Global Education & Learning Series – Life Sciences.
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