Biology

Human Immunity and Blood

2,096 Questions

Human immunity and blood questions cover the physiological mechanisms protecting the body against diseases and the components of blood. Topics include blood groups, cell mediated immunity, monoclonal antibodies, and blood coagulation. These biology topics frequently appear in general science sections of competitive exams.

Blood groupsCell mediated immunityMonoclonal antibodiesBlood coagulationCancer immunology

Human Immunity and Blood Questions

Multiple choice

What are the chemicals produced by macrophages during infection?

  1. Lymphokines

  2. Heparin

  3. Cytokines

  4. Hydrogen peroxide

  5. Histamine
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Cytokines are small proteins which allow cells of the immune system to communicate with one another via cytokine receptors expressed at the cell surface. Interleukin 6 is a pro-inflammatory cytokine and is produced by macrophages in response to infection and tissue injury. IL-6 exerts its effects on multiple cell types and can act systemically.

Multiple choice

A young lady is suffering from Pernicious anaemia, which is an autoimmune disorder in which the body fails to make sufficient RBCs. Which of the following antibodies is/are of most use for the diagnosis of pernicious anaemia in such people?

  1. Anti-parietal cells

  2. Anti-thyroid peroxidase

  3. Anti-nuclear

  4. Anti-IgG Fc

  5. Anti-TSH receptor
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Parietal cell antibodies detected by immunofluorescence in stomach sections are important markers of inflammatory atrophic gastritis and subsequent pernicious anaemia.

Multiple choice

Serum is a clear liquid that can be separated from clotted blood. Specific antibodies are readily detectable in serum following primary contact with antigen after

  1. 10 min

  2. 1 h

  3. 5–7 days

  4. 3–5 weeks

  5. a second contact with antigen
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

5 days or more are required for B-cell proliferation, differentiation into plasma cells, and the secretion of a large enough amount of antibody for it to be readily detected systemically.

Multiple choice

Immunological unresponsiveness to self antigens is known as

  1. tolerance

  2. tolerogen

  3. memory

  4. acquired immunity

  5. ADCC
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Tolerance is a specific immunological non-responsiveness. Whilst tolerance can be induced to any antigen, the mechanism is thought to have evolved as a means of preventing the maturation of pathogenic self-reactive lymphocytes.

Multiple choice

Which of following statements characterises the NZB model of autoimmune haemolytic anaemia in human beings?

  1. There are no T-cell regulatory abnormalities.

  2. Disease is unaffected by neonatal thymectomy.

  3. The red cell autoantibodies cause disease.

  4. CD5 + B-cells are not involved in pathogenesis.

  5. Thyroid autoantibodies are prevalent.
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Transfection with rearranged genes encoding a red cell autoantibody causes early disease in normal animals.

Multiple choice

Cryptic T-cell epitopes

  1. dominate the normal immune response

  2. negatively select T-cells

  3. are unable to bind in the MHC groove

  4. can be derived by antigen processing

  5. are presented by MHC class I, but not MHC class II molecules
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

In order to be T-cell epitopes, i.e. peptides, they must be derived by antigen processing. Qualitative and/or quantitative alterations in processing can lead to greatly increased production of cryptic peptides and thus, may trigger autoimmune disease.

Multiple choice

Autoantigen selection of responding B-cells is indicated by which of the following?

  1. Germ line configuration of the antibody

  2. High affinity of antibody

  3. Expression of a public idiotype

  4. A monoclonal antibody response

  5. A response to many different autoantigens
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

The mutation of the antibody variable region genes in B-cells in the germinal centre produces a range of antibody affinities, and those B-cells bearing higher affinity antibody will be favourably selected for further stimulation by antigen.