1. Which of the following is not part of the mononuclear phagocyte system?
a) Mesangial cells
b) Endothelial cells
c) Kupffer cells
d) Macrophage
Explanation: Endothelial cells are not part of the mononuclear phagocyte system. The macrophages which line the medullary sinuses are part of the mononuclear phagocyte system. Mesangial cells of the kidney, Kupffer cells of the liver, etc. perform phagocytosis and kill the bacteria.
2. Which of the following cells form NET and perform phagocytosis?
a) Lymphocytes
b) Neutrophils
c) Basophils
d) Eosinophils
Explanation: Neutrophils are the granulocytes present in leukocytes that form NET (Neutrophil Extracellular Trap) and trap the microbes and kill them. Neutrophils are the first cells to arrive at the site of inflammation and form NET and perform phagocytosis.
3. Which of the following is not an APC cell?
a) Monocytes
b) Keratinocytes
c) Macrophages
d) Dendritic cells
Explanation: Keratinocytes are not the antigen-presenting cells (APCs). APCs are the cells that present antigens to B cells and T cells. Dendritic cells (DCs), monocytes, macrophages, B cells, etc. are antigen-presenting cells (APCs).
4. Which of the following is an abundant class of antibody in the serum?
a) IgE
b) IgD
c) IgA
d) IgG
Explanation: IgG is the most abundant antibody present in serum i.e. 80%. IgG plays an important role in the neutralization of toxins, providing immunity to newborns, etc.
5. IgM antibody exists as a pentamer.
a) True
b) False
Explanation: IgM antibody exists as a pentamer molecule with five IgM monomers linked at their C-termini. It protects against many viral and bacterial infections and is found in all body fluids.
6. Cytokines coordinate the immune system.
a) True
b) False
Explanation: Cytokines coordinate the immune system and are soluble proteins that are secreted by the specific cells of the immune system. Cytokines include interferons and interleukins which help to regulate the immune system.
7. Which of the following is not the type of viral infection?
a) Null
b) Meningitis
c) Latent
d) Persistent
Explanation: Meningitis is a type of bacterial infection. The interactions between viral and cells can be classified into acutely cytopathogenic, persistent, null, latent, abortive, transforming infections.
8. Which of the following infection is also called as lytic infection?
a) Null
b) Cytopathogenic
c) Latent
d) Abortive
Explanation: Cytopathogenic infections are also called lytic infections as the cell dies due to lysis. But lytic is not the accurate term, as in some infection cells die without being lysed, that is, by apoptosis or programmed cell death.
9. Which of the following virus promotes cell death by apoptosis?
a) Vaccinia virus
b) Myxoma virus
c) HSV
d) Rubella virus
Explanation: Rubella virus, which belongs to the family Togaviridae, expresses proteins that promote the cell death by apoptosis. Vaccinia virus, myxoma virus, herpes simplex virus, etc. are the viruses that inhibit the cell death by apoptosis.
10. Which of the following infection results in the continuous production of viruses?
a) Persistent
b) Abortive
c) Null
d) Transforming
Explanation: Persistent infections are the infections that cause or result in the continuous production of infectious viruses. This is achieved either by the survival of the infected cells or by a situation in which a minority of cells are initially infected and the spread of the virus is limited.