Thursday, 22 January 2009

Retroviruses

Lentivirus (HIV)

HIV stands for human immunodeficiency virus. HIV destroys certain white blood cells called CD4+ T cells. These cells are critical to the normal function of the human immune system, which defends the body against illness. When HIV weakens the immune system, a person is more susceptible to developing a variety of cancers and becoming infected with viruses, bacteria and parasites.
  • envelope with glycoprotein peplomers

  • 2 copies of linear plus sense ssRNA, each 7 to 10kb
  • 3' polyadenylated tail and 5' cap

  • reverse transcriptase (genome doesn't serve as mRNA)


Primary infection

  • acute stage
  • flu-like symptoms
  • fever
  • skin rash
  • swollen lymph nodes
  • rate of replication
  • propensity to mutate
  • cytopathogenicity
  • host resistance (suppresion by CD8 T suppresor cells and presence of cytotoxic T-lymphocytes)

Asymptomatic stage

  • no apparent disease
  • fall in CD4 T lymphocytes (primary target cell)
  • fatigue
  • depression
  • weight loss
  • memory disorders

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