This set of Immunology Multiple Choice Questions & Answers (MCQs) focuses on “Immune Response to Cancer”.
1. Which type of immune system(s) respond to cancer/tumour cells?
a) Innate Immunity
b) Adaptive and Innate Immunity
c) Adaptive Immunity
d) Innate and Responsive Immunity
View Answer
Explanation: The immune system is comprised of both Innate as well as adaptive immune system. Both these systems are responsible for their actions against cancer/tumour cells. Adaptive immune system plays a very important and primary role against tumour cells as it is composed of specialised cells for direct elimination of the toxic cells. On the other hand, even if innate immunity is short lived, it is still able to identify self and non-self-pathogens and can supress the action of toxic pathogens of the tumour environment.
2. Which cells are the key players in regulating cell-mediated innate immune response in order to kill pathogenic cells?
a) Phagocytes
b) NK cells and phagocytes
c) NK cells and leukocytes
d) B cells and phagocytes
View Answer
Explanation: The key players in cell-mediated innate immune responses are NK cells and phagocytes which help in killing the pathogenic cells. They help in providing protection by immediately responding to the host’s needs. They engulf those cells which are capable of expressing nonself-antigens or the self-antigens that undergo alterations. All in all they provide immense protection by associating with MHC class I proteins to kill the pathogens that invade the regularity of immune system.
3. Which immunomodulatory enzyme is associated with mechanisms pf cancer escape and expansion?
a) Tryptophan
b) IDO
c) Kynurenine
d) APCs
View Answer
Explanation: One of the major factors that promotes immune escape and tumour growth in cancer cells is activation of the enzyme indoleamine 2,3-dioxygenase (IDO). It is also termed as immunomodulatory enzyme which is produced by some macrophages and other immunoregulatory cells. IDO catalyses tryptophan (Trp) through the generation of Kynurenine (Kyn). This entirely is said to be the cancer escape mechanism.
4. In the elimination phase of cancer immunoediting, nascent tumour cells recognition takes place.
a) True
b) False
View Answer
Explanation: Cancer immunoediting is a process which comprises of three major phases. These phases are as follows: elimination, equilibrium and escape phase. It is true that in the first phase, i.e., in the elimination phase, nascent tumour cells get recognized in order to undergo elimination. This phase is known as the principle phase as it helps the affected tissues to revert back to their normal state.
5. What does TAAs stand for which is present on the tumour cells?
a) Trimeric autotransporter adhesin
b) Trimeric adaptive adhesin
c) Trimeric autoadaptive activator
d) Trimeric autotransporter activator
View Answer
Explanation: TAAs stands for Trimeric Autotransporter Adhesin and it is a protein which comprises of short amino acids peptide segments. It can be derived from any intracellular protein. They are present on the tumour causing cells. T cells recognise these TAAs through their TCRs with respect to either MHC-I or MHC-II on the surface of tumour cells or APCs respectively. The processing of TAAs takes place by two pathways altogether.
6. Which enzymes do NK cells secrete to kill cancer cells?
a) Perforin and Granzyme
b) Perforin and HLA
c) Granzyme and HLA
d) HLA and MHC I associated proteins
View Answer
Explanation: NK cells play a very important role in regulating as well as protecting the cell-mediated innate immune responses against cancerous cells. They secrete perforin and granzyme to induce apoptosis of the cells that have abnormal or altered MHC class I expression if the cell has been compromised or a pathogen is expressed, Perforin and Grsanzyme together work in order to induce target-cell apoptosis by cooperating with one another.
7. The T cell activation for their action against tumour antigens requires which of the following conditions?
a) It requires two signal process
b) It requires association of Granzyme
c) It requires interaction between TCR and Granzyme
d) It requires three signal process
View Answer
Explanation: T cell activation requires two major signals. These signals are termed as signal 1 and signal 2. T cell activation is delivered with the first signal by carrying out the interaction between TCR and peptide antigens that are associated with MHC molecules. On the other hand, the second signal is delivered for the activation process by various co-stimulatory mechanisms like binding between CD28 and T cells.
8. NK cells need to interact with which receptor in order to kill cancer cells?
a) Antigen presenting receptors
b) Killer-activating receptors
c) T cell receptors
d) NK cells killing receptors
View Answer
Explanation: When normal cells are invaded by any pathogen, they result in causing the cells to become malignant. During the course of malignant transformation of a normal cell to a malignant cell, cancer cells may lose the MHC-I molecule on its cell membrane. This loss triggers the NK cells to carry forward the interaction with these cells. This interaction takes place by KAR i.e., Killer-activating receptors which further leads to activate killing processes.
9. Which types of cells are recruited in periphery by tumour cells?
a) NK cells
b) Cytotoxic T cells
c) Regulatory T cells
d) CD28 cells
View Answer
Explanation: According to the researchers, Regulatory T cells are thought to be recruited in the periphery by the tumour cells themselves. These cells (also termed as Treg cells) functionally suppress immune responses by influencing the activity of another cell type and can occur either by cell-to-cell contact or by the elaboration of immune-regulatory cytokines IL-10 and TGF-β. The immune system suppression by regulatory T cells is one of the most crucial tumour immune evasion mechanisms. This can be a very serious condition as it can even cause complications during cancer immunotherapy.
10. Which pathway causes the tumour cells to release the degraded and unfolded intracellular protein within the complex named proteosome?
a) TAAs processing: exogenous pathway
b) TAAs processing: intracellular pathway
c) TAAs processing: extracellular pathway
d) TAAs processing: endogenous pathway
View Answer
Explanation: TAAs processing consists of 2 pathways: endogenous and exogenous. In the endogenous pathway, degradation of unfolded proteins takes place with the help of tumour cells. This degradation gives rise to short peptides. The next step is followed by transportation through several pathways in the endoplasmic reticulum. These fragments are then loaded onto the MHC-I. The final MHC-I/peptide complexes are then transported to the tumour cell surface through the Golgi apparatus for presentation to CD8+ T cells.
Sanfoundry Global Education & Learning Series – Immunology.
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