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

Type IV hypersensitivity is a cell-mediated immune reaction. Which of the following is true regarding the type IV hypersensitivity?

  1. Specific antibodies are directed against cellular targets.

  2. Complement is involved.

  3. Mast cells play a central role in the effector component.

  4. Th1 cells play a central role in the effector component.

  5. Histology is typically granulomatous.
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

T cells are involved; the principle effector cells are Th1, secreting interferon-gamma and TNF, resulting in activation of macrophages. Th17 cells may also play a role.

Multiple choice

Which of the following statements is true regarding the removal of cells by apoptosis?  

  1. Auto-antigens are frequently methylated and this results directly in autoimmune sensitisation.

  2. C5 plays a central role in cellular clearance.

  3. Apoptosis can also be mediated by T cells using FAS:FAS ligand interactions.

  4. Nuclear material is expanded beneath a blebbed membrane.

  5. Macrophages secrete the pro-inflammatory cytokines IL-10 and TGFβ in response to cellular ingestion.
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

FAS ligand (CD178) is expressed on activated T cells; the interaction with FAS, a protein on many cell types triggers enzymes to degrade the target cell DNA.

Multiple choice

Which of the following concerning diseases involving immunological mechanisms of type II hypersensitivity is CORRECT?    

  1. Type II hypersensitivity involves circulating or tissue-bound immune complexes.

  2. Inflammation occurs within minutes.

  3. May alter the cell metabolism through receptor dysfunction.

  4. Are responsible for lupus nephritis.

  5. Are largely Th1 cytokine dependent.
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Grave's disease results from the binding of specific antibodies to cell-bound antigen, TSH receptor. Activates this receptor and stimulates the thyroid cell to produce thyroid hormone as a result.

Multiple choice

Which of the following is not included in the serological findings in patients with systemic lupus erythematosus (SLE)?

  1. Raised serum IgG levels

  2. Antibodies to double-stranded DNA

  3. Decreased C3 and C4 levels

  4. A positive lupus anticoagulant

  5. Antibodies to cyclic citrullinated peptide (anti-CCP antibodies)
Reveal answer Fill a bubble to check yourself
E Correct answer
Explanation

Anti-CCP antibodies are found in >96% of patients with RA and not in other inflammatory conditions, making this assay specific for RA and therefore useful in clinical practice.

Multiple choice

Th cells are a type of T cell that play an important role in the immune system. Which of the following statements about Th responses is FALSE?  

  1. Th2 cells produce cytokines that favour the production of IgE.

  2. Th1 cells can be found in atopic eczema lesions.

  3. Th2 cells characteristically express the foxp3 gene product.

  4. Th2 cells produce IL-4.

  5. Th1 cells are associated with the transcription factor T-bet.
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Foxp3 is a protein involved in immune system responses. It is associated with regulatory T cells.

Multiple choice

Which of the following statements is NOT thought to be involved in asthma?  

  1. Activation of Th1cells.

  2. Epithelial cell activation occurs.

  3. Upregulation of VCAM-1 results in infiltration of eosinophils.

  4. Adrenaline is always used to reverse bronchoconstriction in mild asthmatics.

  5. Blocking activation of mast cells with a monoclonal antibody to IgE can give clinical benefit.
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Adrenaline is only used in status asthmaticus and never in mild asthma.

Multiple choice

Which of the following statements relating to ‘rheumatoid factor’ is true?

  1. Rheumatoid factor is a poor prognostic factor when found in patients with rheumatoid arthritis.

  2. The finding of rheumatoid factor in a given patient's blood is diagnostic of rheumatoid arthritis.

  3. Rheumatoid factor is an IgE molecule.

  4. Rheumatoid factor can form immune complexes with IgE.

  5. Rheumatoid factors are always found transiently in the blood of patients who have recently suffered from an infection.
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Rheumatoid factor does indicate a poor prognosis when found in RA patients, correlating with extra-articular (non-joint) complications of RA such as nodules, lung disease and vasculitis as well as with severely affected joints.

Multiple choice

RA is a disease of joint destruction; which of the following scenarios is most pertinent to the immunopathogenesis?

  1. Macrophage activation by rheumatoid factor.

  2. The triggering factor is Campylobacter jejuni.

  3. CD4 T cells produce TNF-α cytokine that activates macrophages.

  4. The acute phase response that accompanies active RA disease suggests that persistent infection is a factor.

  5. MHC association with HLA B27 is important in Europeans and RA is restricted to this group of individuals.
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

In RA, CD4 T cells produce cytokines including Tumour Necrosis Factor [TNF], which activates macrophages to produce tissue destroying enzymes and remodelling cytokines which deform the affected joints. Anti-TNF therapies provide potent therapies for many but not all patients with RA.

Multiple choice

Cryoglobulins are immune complexes that precipitate at low temperatures. Which one of the following is the correct statement about cryoglobulins?    

  1. Samples for cryoglobulin detection must be stored on ice before they reach the laboratory.

  2. Type III cryoglobulins are associated with hepatitis C infection.

  3. Type I cryoglobulins are monoclonal proteins typically of IgA or IgD class.

  4. Cryoglobulins are always monoclonal immunoglobulins.

  5. Cryoglobulins precipitates from the blood serum in extremely hot and arid conditions.
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Type III cryoglobulins are formed through mixed complexes of polyclonal antibodies with antigen, usually in the form of large complexes; there is a strong association with hepatitis C.

Multiple choice

In a thymectomized organism, which of the following is irradiated and reconstituted with bone marrow cells?

  1. The T-lymphocyte population is not restored.

  2. The B-lymphocyte population is not restored.

  3. All lymphocyte populations are restored.

  4. None of the lymphocyte populations are restored.

  5. Rapid death inevitably follows.
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Immature lymphocytes which are destined to become T-cells travel from the bone marrow to the thymus where they differentiate to immunocompetence and are educated to recognize peptides derived from foreign antigens presented by self MHC molecules. Thus in a thymectomized animal, this process cannot take place.