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

The activation of which of the following is responsible for early ethanol-induced liver injury in human beings?

  1. Mesothelium

  2. Stellate cells

  3. Kupffer cells

  4. Hepatocytes

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

Kupffer cell activation is responsible for early ethanol-induced liver injury, common in chronic alcoholics. Chronic alcoholism and liver injury deal with a two hit system. The second hit is characterised by an activation of the Toll-like receptor 4 (TLR4) and CD14, receptors on the Kupffer cell that internalise endotoxin (lipopolysaccharide or LPS).

Multiple choice

Intrinsic factor (IF) is a protein produced by the parietal cells of the stomach. Which of the following statements about intrinsic factor autoantibodies is true?

  1. They are found in less than 40% of patients with pernicious anaemia.

  2. They are found in about 25% of patients with iron-deficiency anaemia.

  3. They are more frequently found in serum than gastric juice.

  4. They are more often binding (type II) than blocking (type I).

  5. They are helpful in the diagnosis of pernicious anaemia.
Reveal answer Fill a bubble to check yourself
E Correct answer
Explanation

Intrinsic factor antibodies are specific and rarely occur in the absence of latent or overt pernicious anaemia, although a low serum B12 level and a positive gastric parietal cell antibody allows a presumptive diagnosis of PA to be made.

Multiple choice

The intraepithelial lymphocytes are situated in the epithelium of the intestine and are regarded as an essential part of the immune system. Which of the following characteristically is NOT expressed by the main populations of intraepithelial lymphocytes?

  1. CD 19

  2. CD 103

  3. The γδ form T-cell receptor [TCR]

  4. αβ form of the T-cell receptor [TCR]

  5. CD8
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Intraepithelial lymphocytes are T cells of various types, not B cells. CD19 is a B cell marker.

Multiple choice

An antigen is a substance that causes the immune system to produce antibodies against itself. Which type of cells are known to be involved in the initial presentation of antigen to T lymphocytes?

  1. Dendritic cells

  2. Plasma cells

  3. Neutrophil polymorphonuclear leucocytes

  4. Erythrocytes

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

Dendritic cells are professional antigen processing cells. They have a number of receptors that enhance the uptake of antigens, and they specialise in converting these antigens into MHC-peptide complexes that can be recognised by lymphocytes.

Multiple choice

Lymphocytes are an important part of the immune system. Which of the following specialised cell types are involved in the entry of lymphocytes into the lymph nodes?

  1. M-cells

  2. Mesangial cells

  3. PALS

  4. HEV endothelial cells

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

The high-walled endothelium of the post-capillary venules (HEV) in lymph nodes express vascular addressins which are recognised by homing receptors on lymphocytes passing through the afferent lymphatics and which mediate entry of the lymphocytes into the lymph nodes.

Multiple choice

Which among the following tingible bodies are present inside the germinal center macrophages of the immune system?

  1. DNA fragments

  2. Phagocytosed foreign antigen

  3. A sign of macrophage apoptosis

  4. Bacterial cell wall components resistant to degradation

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

There is very extensive apoptotic cell death amongst light zone centrocytes and the resultant DNA fragments are visible as 'tingible bodies' within the macrophages which have phagocytosed the apoptotic lymphocytes.

Multiple choice

Immunoglobulin E (IgE) is a type of antibody that is present in minute amounts in the body but plays a major role in allergic diseases. Which of the following types of cells produce IgE?

  1. Mast cells

  2. Eosinophils

  3. Basophils

  4. Plasma cells

  5. T lymphocytes
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

A plasma cell is a mature B lymphocyte that is specialised for antibody (immunoglobulin) production. Plasma cells are rarely found in the peripheral blood. They comprise 0.2% to 2.8% of the bone marrow white cell count. These cells produce immunoglobulins of all isotypes, including IgE.

Multiple choice

Monocytes and macrophages are critical effectors and regulators of inflammation and the innate immune response of the body. Which of the following cells are not thought to be of monocyte-macrophage lineage?

  1. Neutrophils

  2. Follicular dendritic cells of lymph nodes

  3. Kupffer cells in liver

  4. Histiocytes in tissues

  5. Monocytes in blood
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

These are of the myeloid lineage which separates from the monocyte-macrophage lineage after the pluripotent stem cell stage.

Multiple choice

The lymphoid tissues in the adult immune system serve as primary and secondary depots of cells being involved in the immune response. Which of the following lymphoid tissues is unencapsulated?

  1. Thymus

  2. Lymph node

  3. Spleen

  4. Tonsil

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

The respiratory, alimentary and genitourinary tracts are guarded immunologically by subepithelial accumulations of lymphoid tissues which are not constrained by a connective tissue capsule. These may occur as diffuse collections of lymphocytes, plasma cells and phagocytes throughout the body and the lamina propria of the intestinal wall, or as more clearly organised tissue with well-formed follicles as found in the Peyer's patches.

Multiple choice

Phagocytosis is a process by which certain living cells ingest or engulf other cells or particles. Which of the following cell types are phagocytic in nature?

  1. Hepatocytes

  2. Lymphocytes

  3. Monocytes

  4. Erythrocytes

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

Phagocytosis is the process of uptake of microbes and particles followed by digestion and destruction of this material. Monocytes can perform phagocytosis using intermediary (opsonising) proteins such as antibodies or complement that coat the pathogen, as well as by binding to the microbe directly via pattern-recognition receptors that recognise pathogens.