Immune system disorders

• What does HIV do?

  Infects and destroys T-Helper cells.
• How does HIV develop into AIDS.

  Destruction of T-Helper cells results in a loss of B and Cytotoxic T-cell mediated immunity as they require activation from T-helper cells.
• What is the clinical presentation of AIDS.

  Reaccurent oportunistic infections.
• Example of an opportunistic infection.

  Pneumonia.
• Which glycoprotein binds to CD4 and what is its name.

  GP120, Docking.
• Which glycoprotein binds to CXCR4 and what is its name.

  GP41, transmembrane.
• What is the role of reverse transcripatse in HIV.

  Reversibely transcribes Viral RNA to DNA for insertion into Host's DNA.
• What type of virus is HIV.

  Retrovirus.
• What are the 3 molecules detected for HIV testing.

  Antibodies, Viral RNA and T-Helper cell numbers.
• What type of test identifies HIV antibodies.

  Seroconversion.
• When is Viral RNA used for HIV diagnosis.

  During the window period.
• What is the purpose of FACS/flow cytomertry testing.

  Disease monitoring of T-helper numbers.
• What is the Windown Period.

  2-8 weeks post-infection prior to antibody production.
• Describe Viral RNA detection test.

  
  

  1. cDNA production using RT and DNA polymerase
  2. PCR to amplify DNA [95, 68, 72]
  3. Gel electropheresis to compare DNA bands with controls
• Describe how T-helper cell count is determined.

  
  

  1. Mix blood and flourescently labelled CD4 antibody
  2. Stream through flow cell
  3. Detect flourescent light
• Is >500 CD4+/ul Healthy or not.

  Healthy.
• Is <200 CD4+/ul Healthy or not.

  AIDS.
• Is 200-500 CD4+/ul healthy or not.

  Abnormal.
• Name the 3 seroconversion tests.

  
  

  1. Latex particle agglutination
  2. ELISA
  3. Immunochromatography
• Describe Latex particle agglutination

  
  

  1. Latex particle covered in HIV antigen
  2. Add sample
  3. Visible agglutination [cloudy]
• Describe the immunochromatography test

  1. Add sample
  2. Control line binds to antigen
  3. Test line binds to Antigen-antibody complex

  A) Sample port

  B) Control line

  C) HIV test line

  
• Is multiple myeloma an autoimmune disease

  no
• Describe the ELISA for HIV

  1. HIV antigen bound to well
  2. Wash
  3. Add serum
  4. Wash
  5. Add enzyme labelled anti-human antibody [Alkaline phosphatase]
  6. Wash
  7. Add chromogenic substrate [BCIP
• What is the colour change in a HIV elisa

  Colourless to purple
• What is the clinical presentation of Multiple myeloma

  Anaemia.

  Tachycardia.

  Recurrent infections.

  Fragile bones.
• What causes fragile bones in multiple myeloma

  Osteoclasts activity is increased by the malignant plasma cells, causing them to dissolve bone.
• Define multiple myeloma

  It is a cancerous proliferation of a single clone of an immunoglobulin producing plasma cell in the bone marrow.
• What is the pathology of multiple myeloma

  There is a large amount of paraprotein
• What type of molecule is paraprotein

  An immunoglobulin
• How is multiple myeloma diagnosed

  Cellulose acetate electrophoresis is conducted on a serum sample to see if there is an increased presence of paraprotein.

  A urine sample can be analysed for the light chains of the paraprotein antibody.
• What are the bence jones proteins

  These are the light chain of the paraprotein antibody. This is used as a detection method using a urine sample for multiple myeloma.
• What pH is used in cellulose acetate electrophoresis

  6.8
• Why do proteins migrate to the anode in cellulose acetate electrophoresis.

  At pH 8.6 the overall charge of the amino acids is negative as the amino and carboxyl groups are deprotonated.
• How are the bands in cellulose acetate visualised

  You immerse it in trichloroacetic acid. This protonates the amino and carboxyl groups.

  Then add ponceau s which is a stain. This binds to the positively charged proteins.
• What is the condition when the immune system attacks its own cells

  Autoimmunity
• What type of condition is pernicious anemia

  Autoimmune
• What is the pathology of pernicious anaemia

  Autoantibodies are produced against the gastric parietal cells. This results in less intrinsic factor being produced and less vitamin B12 absorption.

  Vitamin B12 is required for DNA synthesis and red blood cell production which is what causes the anemia.
• What technique is used to diagnose pernicious anaemia

  Indirect immuno-fluorescence
• Describe the process of indirect immuno-fluorescence

  Gastric parietal cells are fixed to a glass microscope slide.

  Add patient serum.

  Add fluorescently labelled anti-human antibodies.

  Examine with a microscope and UV light.
• Is the heavy immunoglobulin chain species specific

  Yes