Immunodeficiency & HIV

• What can the immune system be divided into?

  Innate-the one that we are born with & our first response (e.g. phagocytes, complement, etc.)

  Adaptive/acquired-changes throughout life (e.g. T cells, B cells, etc.)

  central role of the immune system is to protect against microbial pathogens
• What does immunodeficiency result in & what is an indication of immunodeficiency?

  -Immunodeficiency results in increased susceptibility to infection by specific classes or types of microbes

  
  

  -Repeated or unusual infections is an indication of immunodeficiency
• What is primary & secondary immunodeficiency?

  Primary immunodeficiency:

  -Genetically determined

  -or result of developmental anomalies

  -Inherited, congenital, and rare

  
  

  Secondary immunodeficiency:

  -Acquired & caused by disease or an immunosuppressive treatment

  -More common
• What can primary immunodeficiencies be a result of?

  It can be genetic so:-autosomal-X-linked (sex chromosome)-gene deletions, rearrangements, polymorphisms (SNPs)

  Or

  it can be biochemical or metabolic so:-adenosine deaminase deficiency (affects T cells),-purine nucleoside phosphorylase deficiency (affects T cells)-developmental arrest (affects B cells, T cells, phagocytes)
• What are some examples of complement deficiencies?

  
• What are some examples of phagocytosis deficiencies?

  
• What are some examples of humoral/antibody deficiencies?

  
• What are some examples of T cell deficiencies?

  
• What are some clinical features of immunodeficiencies?

  Chronic and recurrent infections

  Unusual microbial agents

  Incomplete responses to treatment

  Skin lesions, warts

  Diarrhoea

  Recurrent abscesses

  Autoimmunity

  Failure to thrive
• What are some examples of causes of secondary immunodeficiencies?

  Therapeutic drugs (cancer chemotherapy, radiation therapy, post-transplant immunosuppression)

  
  

  Infection (HIV/AIDS)

  
  

  Metabolic / chronic disorders (ex: diabetes)

  
  

  Malnutrition, aging

  
  

  Burns/trauma (loss of immunoglobulin via damaged skin)
• Describe the human immunodeficiency virus.

  -Causative AIDS agent

  
  

  Group VI of Baltimore virus classification (ssRNA virus with a DNA intermediate)

  
  

  Hallmarks of this virus is its ability to reverse transcribe (RNA-->DNA) & chromosomal integration

  
• What 3 main genes are in the proviral DNA of HIV?

  gag- codes for structural proteins

  
  

  pol- codes for viral enzymes

  
  

  env- codes for the viral protein

  
• What are the steps of the HIV life cycle & cell entry?

  1. receptor binding

  2. Membrane fusion + entry

  3.Uncoating +reverse transcription

  4.Nuclear uptake

  5.Integration

  6.Transcription

  7.RNA processing

  8.Nuclear export

  9.Translation

  10.assembly

  
• How do attachment factors differ from receptors?

  Attachment factors are not essential

  
• describe the course of infection : HIV to AIDS

  
• When is AIDS diagnosed?

  At CD4 less than 200 cells and/or presence of opportunistic infection

  
  

  Aids = CD4 T cell reduction

  
• What happens once an individual is diagnosed with AIDS?

  The host will not be able to mount a proper immune response against other infectious agents such as:

  
  

  parasites, bacteria, fungi, viruses
• Which malignancies are common in people with AIDS?

  Kaposi's sarcoma

  Non-Hodgkin's lymphoma (including Burkitt's lymphoma)

  Primary CNS lymphoma

  Invasive cervical cancer

  Increased rates of other cancers
• Summarise the content in this lecture.