Tissue tropism

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Tissue tropism is the cells and tissues of a host which support growth of a particular virus or bacteria. Some bacteria and viruses have a broad tissue tropism and can infect many types of cells and tissues. Other viruses may infect primarily a single tissue. For example rabies virus affects primarily neuronal tissue.

Influencing factors[edit]

Factors influencing viral tissue tropism include:

The cellular receptors are the proteins found on a cell or viral surface. These receptors are like keys allowing the viral cell to fuse with a cell, or attach itself to a cell. The way that these proteins are acquired is through similar process to that of an infection cycle.

How 'tropic' tissue is acquired[edit]

HIV

Tissue tropism develops in the following stages:

  • Virus with GPX enters body (where GP - glycoprotein and X is the numeric value given to the GP)
  • Viral Cell 'targets' cell with a GPX receptors
  • Viral Cell fuses with the cell and inserts its contents into it
  • Reverse Transcription occurs
  • Viral DNA is incorporated with host DNA via Viral Enzyme
  • Production of RNA and Viral Protein
  • Viral particle is assembled
  • Viral particle buds out of the cell taking a chunk of the cell membrane with it acquiring a new tissue with all the receptors it needs to continue Tissue Tropism

Example: HIV has a gp120 which is precisely what the CD4 marker is on the surface of the macrophages and T cells, thus HIV can enter T cells and macrophages

References[edit]

  • Raven, Peter H.(2008). "Biology 8th Edition". New York, McGraw-Hill.