Biology

Human Immunity and Blood

2,051 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

The most defining feature of a regulatory T-cell is

  1. expression of CD4

  2. expression of Foxp3

  3. production of IL-10

  4. that it can be induced by TGF

  5. expression of CD25
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Expression of Foxp3 transcription factor is the best 'marker' that correlates with regulatory T-cell activity.

Multiple choice

The systemic lupus erythematosus (SLE) is characterised by

  1. a type III hypersensitivity

  2. an autoimmune disease

  3. a disease that often affects the skin

  4. a disease that often affects the kidneys

  5. a disease in which characteristically anti-DNA auto antibodies are present
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Although patients with SLE often develop an immune complex mediated glomerulonephritis, this is not the single best defining feature. Patients with SLE very characteristically possess anti-nuclear antibodies (ANA), including antibodies against DNA.

Multiple choice

Which of these statements concerning platelets is not true?

  1. They extrude their nucleus as they pass through the spleen.

  2. The megakaryocyte matures by endomitotic synchronous replication so that the number of nuclear lobes increases within the cell.

  3. Thrombopoietin is the major regulator of platelet production, and is produced by the liver and kidneys.

  4. The platelet lifespan is 7-10 days.

  5. The platelets provide phospholipid for the initiation of the coagulation process.
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

This is an incorrect statement as the platelets bud off from megakaryocytes, and never have a nucleus.

Multiple choice

Which of the following transfusions is likely to cause intravascular haemolysis?

  1. Group O blood to group A recipient

  2. Group B blood to group O recipient

  3. Group O blood to group AB recipient

  4. Rh positive blood to a Rh negative donor

  5. Rh negative blood to a Rh positive donor
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

When group B blood is transfused to group O recipient, it will cause intravascular haemolysis as the recipient has anti-B antibodies.

Multiple choice

Which among the following statements regarding haemostasis is not true?

  1. Platelet activation stimulates production of thromboxane A2 (TXA2) by cyclooxygenase (COX).

  2. Aggregation of platelets is stimulated by ADP via P2Y receptors.

  3. Primary haemostasis initially involves vasodailation.

  4. Fibrin is broken down by plasmin.

  5. Binding of thrombin to thrombomodulin prevents cleavage of fibrinogen.
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Primary haemostasis initially involves vasoconstriction in response to vascular damage which limits blood loss, and platelet adhesion and activation due to exposure and binding to subendothelial matrix.

Multiple choice

Agglutinin is an antibody which aggregates a particulate antigen on BBCs. Wheat germ agglutinin binds strongly to

  1. surface lipoproteins on resting T-cells

  2. surface glycoproteins on resting T-cells

  3. surface glycoproteins on resting B-cells

  4. surface glycoproteins on activated T- and B-cells

  5. surface lipoproteins on activated T- and B-cells
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Within 24 h of stimulation by lymphocyte polyclonal activators, high concentrations of binding sites for this lectin appear on the surface of the cell.

Multiple choice

The Rh (Rhesus) blood group is related to

  1. A Antigen

  2. B Antigen

  3. O Antigen

  4. AB Antigen

  5. D antigen
Reveal answer Fill a bubble to check yourself
E Correct answer
Explanation

The Rh (Rhesus) blood group is related to D antigen on red cells, present in 85% of the population (Rh+).Antibody to D antigen can be raised in Rh individuals by transfusion of Rh+ blood or when red cells from a Rh+ fetus enter the circulation of a Rh mother. This can cause haemolytic disease of the newborn .