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I've seen this question about HPV and the reference therein. The link states "Human papillomavirus (HPV) is a DNA virus that presents tropism for epithelial cells, causing infections of the skin and mucous membranes. Replication of HPV occurs in the nuclei of squamous cells and its life cycle is directly related to the differentiation program of the host cell. "

Why does HPV infect squamous epithelial cells and not others, what are the major differences? And why can't that difference be used to provide medication?

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The answer usually lies in whether the cell of interest expresses the correct receptor.

Check this:

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2820467/

This excerpt from that review explains why:

"Although both the α6β4 and α6β1 heterodimer were capable of binding VLPs in vitro, only the former was supposed to function as a HPV receptor, which was concluded from the results that the α6 subunit associated preferentially with the β4 in epithelial cells [12], and the α6β4 complex was expressed exclusively in the basal cellular layer of the stratified squamous epithelium [13], which was presumably the only site of productive PV infection"

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  • $\begingroup$ Given the question, does this mean how receptors are only expressed in squamous cells? $\endgroup$
    – AliceD
    Feb 13, 2016 at 6:58
  • $\begingroup$ A receptor is usually a molecule that the cell uses for a particular function relevant to its extracellular context. In this case integrins mediate cell-cell and cell-matrix interactions with other cells and the extracellular matrix specific to squamous epithelial cells. $\endgroup$
    – nbafrank
    Feb 13, 2016 at 7:02
  • $\begingroup$ Just to clarify, whether a receptor is SOLELY expressed in one cell type is a reflection of its endogenous functions! $\endgroup$
    – nbafrank
    Feb 13, 2016 at 7:04
  • $\begingroup$ I understand all that. I'm just of the opinion the answer touches on the question, but doesn't answer it, given Why does HPV infect squamous epithelial cells and not others $\endgroup$
    – AliceD
    Feb 13, 2016 at 8:30
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    $\begingroup$ The mechanistic reason of why HPV infects ONLY squamous epithelial cells is because its receptor is expressed ONLY on squamous epithelial cells. From a virus advantage point of view, squamous epithelial cells are the outmost layer of epithelial cells, so perhaps the virus evolved that way because they are the first cells it reaches to from the outside. If it had let's say evolved to infect only a lower level epithelial layer then perhaps its virulence would be lower and would be @ risk of becoming extinct. Perhaps it has happened historically and we don't have record of it. $\endgroup$
    – nbafrank
    Feb 13, 2016 at 19:53

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