This set of Immunology Multiple Choice Questions & Answers (MCQs) focuses on “B-Cell Receptor and T-Cell Receptor Expression – Set 2”.
1. T cell receptors recognize the antigen bound to __________
a) B cells
b) MHCs
c) T cells
d) Antibodies
View Answer
Explanation: T cell receptors recognize the antigens that are presented as peptides which are bound to MHCs, Major Histocompatibility Complexes. These are present on both B cells and T cells.
2. The affinity of the binding between TCR and antigen is low and it is degenerate. True/False?
a) True
b) False
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Explanation: The above statement is true because many TCRs recognize the same antigen and many antigens are recognized by the same TCR which lacks both specificity affinity.
3. Where does the development and organization of TCR take place?
a) Bone marrow
b) Thymus
c) Spleen
d) Lymphatic tissue
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Explanation: The organization and the development of a T cell and its T cell receptor takes place in Thymus. Before activation these T cells are called thymocytes.
4. Which of the following is associated with T cell Receptor?
a) CD3
b) CD24
c) CD59
d) CD79
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Explanation: 95% of the T cell receptor complexes are composed of a TCR-alpha, a TCR-beta, a zeta chain and CD3. CD3 helps in activating both Tc and Th cells.
5. Earlier, TCR is known as the “holy Grail of Immunology”.
a) True
b) False
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Explanation: Yes, the structure of TCR is known as the “Holy Grail of Immunology” because of its critical part played in the immune responses. The name came after the capture of T cell interaction with peptide-MHC complex using X-ray crystallography.
6. Which of the following in a TCR is most responsible for recognizing the processed antigen?
a) CDR1
b) CDR2
c) CDR3
d) CDR4
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Explanation: Among all the hypervariable regions in a T cell receptor, CDR3 is the most responsible in recognizing and binding to the antigen that is processed by APCs.
7. The N-terminal of the antigenic peptide interacts with which part of the TCR?
a) CDR1 of alpha chain
b) CDR1 of beta chain
c) CDR2 of alpha chain
d) CDR2 of beta chain
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Explanation: When all the CDRs are responsible for antigen recognition, CDR1 of alpha chain specifically interacts with N-terminal of the antigenic peptide.
8. The C-terminal of the antigenic peptide interacts with which part of the TCR?
a) CDR1 of alpha chain
b) CDR1 of beta chain
c) CDR2 of alpha chain
d) CDR2 of beta chain
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Explanation: The CDR1 of beta chain in a T cell receptor (TCR) interacts with the C-terminal of the antigenic peptide. The interaction will be at an angle of 45° in order to ensure the proper interaction.
9. Which of the following in a TCR recognizes MHCs?
a) CDR1
b) CDR2
c) CDR3
d) CDR4
View Answer
Explanation: Among all the CDRs of a T cell Receptor, the major histocompatibility complexes (MHCs) are recognized by the CDR2. As a result a TCR Vβ CDR2 loop forms which is the basic requirement for any interaction to happen.
10. Which of the following interacts with superantigens?
a) CDR1 of beta chain
b) CDR2 of beta chain
c) CDR3 of beta chain
d) CDR4 of beta chain
View Answer
Explanation: CDR4 of the beta chain in a T cell receptor does not participate in antigen recognition, instead it interacts with the superantigens, the antigens which interact with both MHCs and the TCRs simultaneously.
Sanfoundry Global Education & Learning Series – Immunology.
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