Tag: active and passive immunity

Questions Related to active and passive immunity

T-cells respond to pathogens by producing 

bio-chemistry immunity and blood groups active and passive immunity acquired immunity innate and acquired immunity

  1. Killer T-cells

  2. Helper T-cells

  3. Supressor T-cells and memory cells

  4. Killer T-cells, helper T-cells and supressor T-cells

Show answer
Correct Option: D
Explanation:

T cell is a type of WBC that plays a central role in cell-mediated immunity. They are called T cells because they mature in the thymus from thymocytes. T cells kill the pathogen by producing - 

  • T-helper cells - It causes maturation of B cells into plasma cells and memory B cells, and activation of cytotoxic T cells and macrophages.
  • Killer T-cells - They destroy virus-infected cells and tumour cells, and are also implicated in transplant rejection.
  • Suppressor T-cells - They are crucial for the maintenance of immunological tolerance. Their major role is to stop T cell-mediated immunity toward the end of an immune reaction.
So, the correct answer is 'Killer T-cells, helper T-cells and suppressor T-cells'.

What is true about T-lymphocytes in mammals : -

bio-chemistry immunity and blood groups active and passive immunity acquired immunity innate and acquired immunity

  1. There are three main types-cytotoxic T-cells, helper T-cells and suppressor T-cells

  2. These originate in lymphoid tissues

  3. They scavenge damaged cells and cellular debris

  4. These are produced in thyroid

Show answer
Correct Option: A
Explanation:
T cells account for about 80% of all lymphocytes. They are named T cells because they mature in the thymus, a gland found in the chest. There are three types of T cell lymphocytes:
  • Cytotoxic T cell
  •  Suppressor T cell
  •  Helper T cell
Helper T cells are arguably the most important cells in adaptive immunity, as they are required for almost all adaptive immune responses. They not only help activate B cells to secrete antibodies and macrophages to destroy ingested microbes, but they also help activate cytotoxic T cells to kill infected target cells. A cytotoxic T cell is a T lymphocyte (a type of white blood cell) that kills cancer cells, cells that are infected (particularly with viruses), or cells that are damaged in other ways. The regulatory T cells formerly known as suppressor T cells are a subpopulation of T cells that modulate the immune system, maintain tolerance to self-antigens, and prevent autoimmune disease.

So, the correct answer is 'There are three main types-cytotoxic T-cells, helper T-cells, and suppressor T-cells'.

The cells which have CD - 8 markers on the cell membrane are

bio-chemistry immunity and blood groups active and passive immunity acquired immunity innate and acquired immunity

  1. B-lymphocytes

  2. Natural killer cells

  3. T-cytotoxic cells

  4. T-helper cells

Show answer
Correct Option: C
Explanation:
  • A cytotoxic T cell (also known as TC, cytotoxic T lymphocyte, CTL, T-killer cell, cytolytic T cell, CD8+ T-cell or killer T cell) is a T lymphocyte (a type of white blood cell) that kills cancer cells, cells that are infected (particularly with viruses), or cells that are damaged in other ways..
  • They have CD - 8 markers on the cell membrane.
  •  When cytotoxic T cells recognize (bind to) their target, they produce more FasL at their surface. This binds with the Fas on the surface of the target cell leading to its death by apoptosis. Hence The cells which have CD - 8 markers on the cell membrane are T-cytotoxic cells.
  • So, the correct answer is 'T-cytotoxic cells'.

Which antibodies activate B Lymphocyte

bio-chemistry immunity and blood groups active and passive immunity acquired immunity innate and acquired immunity

  1. IgA

  2. IgD

  3. IgE

  4. IgM

Show answer
Correct Option: A
Explanation:

The humoral immune response is governed by the antibodies that are secreted by the activated B cells. These are activated by Immunoglobulins A(IgA).

So, the correct option is ‘IgA’.

What are the chemicals secreted by damaged mast cell of connective tissue?

bio-chemistry immunity and blood groups active and passive immunity acquired immunity innate and acquired immunity

  1. Pepsin and renin

  2. Lysozyme and somatostatin

  3. Melanin and coherin

  4. Histamine and heparin

Show answer
Correct Option: D
Explanation:
  • A mast cell is a resident cell of connective tissue that contains many granules rich in histamine and heparin.
  • Mast cells are allergy cells responsible for immediate allergic reactions. They cause allergic symptoms by releasing Histamine and heparin.
  • Hence the chemicals secreted by damaged mast cell of connective tissue are Histamine and heparin.
  • So, the correct answer is 'Histamine and heparin'.

Which Antibodies is produced in primary immune response?

bio-chemistry immunity and blood groups active and passive immunity acquired immunity innate and acquired immunity

  1. $IgA$

  2. $IgE$

  3. $IgM$

  4. $IgG$

Show answer
Correct Option: A

Which of the following cells is incorrectly paired with its function ?

bio-chemistry immunity and blood groups active and passive immunity acquired immunity innate and acquired immunity

  1. Plasma cell-produces antibodies Helper T-cell-lyses foreign cells

  2. Helper T-cell-lyses foreign cells

  3. Memory cell-rapidly proliferates into clones of effector cells when it encounters antigen

  4. Macrophage-engulfs bacteria and viruses

Show answer
Correct Option: B
Explanation:

A- B cells differentiate into plasma cells that produce antibody molecules closely modeled after the receptors of the precursor B cell. Once released into the blood and lymph, these antibody molecules bind to the target antigen (foreign substance) and initiate its neutralization or destruction.

B- Helper T cells are arguably the most important cells in adaptive immunity, as they are required for almost all adaptive immune responses. They not only help activate B cells to secrete antibodies and macrophages to destroy ingested microbes, but they also help activate cytotoxic T cells to kill infected target cells.
C-  B lymphocytes are the cells of the immune system that make antibodies to invading pathogens like viruses. They form memory cells that remember the same pathogen for faster antibody production in future infections.
D- The macrophage is a large white blood cell that is an integral part of our immune system. Its job is to locate microscopic foreign bodies and 'eat' them. Macrophages use the process of phagocytosis to engulf particles and then digest them.

So, the correct option is 'Option B'.

Antigenic determinants bind to which of the following portions of an antibody?

bio-chemistry immunity and blood groups active and passive immunity acquired immunity innate and acquired immunity

  1. Variable regions

  2. Constant region

  3. Only light chains

  4. Only heavy chains

Show answer
Correct Option: A
Explanation:

The specific region on an antigen that an antibody recognizes and binds to is called the epitope, or antigenic determinant. An epitope is usually 5-8 amino acids long on the surface of the protein. Proteins are three dimensionally folded structures, and an epitope may only be recognized in its form as it exists in solution, or its native form. The antigen binding portion of an antibody varies extensively among secreted antibodies, and this length of sequence is known as the variable region. The variable region construction during antibody production in the B cell is what enables antibodies to be generated against an infinite variety of antigens. The other biological properties of the antibody and its role in signaling to other immune cells are determined by the constant regions of the heavy chains.


So, the correct option is 'Variable regions'.

Which of the following molecule is incorrectly paired with its action ?

bio-chemistry immunity and blood groups active and passive immunity acquired immunity innate and acquired immunity

  1. Interleukin I-stimulates division of helper T-cells

  2. Interferon-helps neighbouring cells to resist viral infection

  3. Histamine-fights allergic reactions

  4. Lysozyme-attacks bacterial cell walls

Show answer
Correct Option: C
Explanation:

A- IL-1α is produced mainly by activated macrophages, as well as neutrophils, epithelial cells, and endothelial cells. It possesses metabolic, physiological, haematopoietic activities, and plays one of the central roles in the regulation of the immune responses. It binds to the interleukin-1 receptor.

B- Interferons (IFNs) are a group of signaling proteins made and released by host cells in response to the presence of several viruses. In a typical scenario, a virus-infected cell will release interferons causing nearby cells to heighten their anti-viral defenses.
C- When they leave the mast cells, histamines boost blood flow in the area of your body the allergen affected. This causes inflammation, which lets other chemicals from your immune system step in to do repair work.
D- Lysozyme is capable of breaking the chemical bonds in the outer cell wall of the bacteria. Bacterial cell walls contain a layer of peptidoglycan, which is the specific site that lysozyme targets. The peptidoglycan layer contains alternating molecules called N-acetylglucosamine and N-acetylmuramic acid. 

So, the correct option is 'Option C'.

Find the correct statement with respect to HLA system. 

bio-chemistry immunity and blood groups active and passive immunity acquired immunity innate and acquired immunity

  1. Each individual inherit one pair of haplotype from each parent.

  2. Siblings will have identical haplotype.

  3. MHC - 1 protein present on all cells including erythrocytes.

  4. Macrophages, B-cells, dendritic cells have MHC - II protein on its surface.

Show answer
Correct Option: A
Explanation:

a) HLA system is also called as human leukocyte antigen system. It is a gene complex which encodes for the major histocompatibility complex (MHC) in humans. HLA haplotype is the set of histocompatibility genes that are on the same chromosome and are inherited together. Each individual inherits one pair of HLA haplotypes from each parent. 

b) Each parent has 2 HLA haplotypes on the chromosomes. Hence, there are 1 in 4 chance siblings will have identical haplotype. 
c) MHC I protein is present on all nucleated cells. Since erythrocytes are enucleated, they do not have MHC I proteins on them. 
MHC II protein is present on surface of marcophages, monocytes and dendritic cells. These are responsible for antigen presentation to T cells.
Thus, the correct answer is 'Each individual inherit one pair of the haplotype from each parent.'