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The envelope glycoprotein of simian immunodeficiency virus contains an enterotoxin domain

C L Swaggerty1, A A Frolov, M J McArthur

  • 1Department of Pathobiology, Texas A&M University, College Station, Texas 77843-4467, USA.

Virology
|November 18, 2000
PubMed

Insights

The simian immunodeficiency virus (SIV) surface unit (SU) acts as a viral enterotoxin, causing diarrhea and fluid accumulation in mice. This discovery identifies a second viral enterotoxin, highlighting SIV

Area of Science:

  • Virology
  • Gastroenterology
  • Immunology

Background:

  • The simian immunodeficiency virus (SIV) is a pathogen with complex effects.
  • Viral enterotoxins contribute to gastrointestinal pathology in various infections.
  • The specific enteropathic mechanisms of SIV components remain incompletely understood.

Purpose of the Study:

  • To investigate the enteropathic potential of the SIV surface unit (SU) envelope glycoprotein.
  • To determine if SIV SU possesses enterotoxin-like activity.
  • To elucidate the cellular mechanisms underlying SIV SU-induced intestinal dysfunction.

Main Methods:

  • Administration of purified SIV SU to a mouse model (pups and adult intestinal loops).
  • Assessment of diarrheal response, fluid accumulation, and histological alterations.
  • Ussing chamber experiments to measure chloride secretion in intestinal mucosa.
  • Intracellular calcium and inositol 1,4,5-triphosphate (IP(3)) level measurements in HT-29 cells.

Main Results:

  • Intraperitoneal administration of SIV SU induced a dose-dependent diarrheal response in mouse pups.
  • Intestinal loops treated with SU showed fluid accumulation but no histological damage.
  • SU-treated intestinal mucosa exhibited induced chloride secretory currents.
  • SIV SU triggered a transient increase in intracellular calcium and IP(3) levels in HT-29 cells, indicating IP(3)-mediated calcium signaling.

Conclusions:

  • The SIV surface unit (SU) contains an enterotoxic domain.
  • SIV SU functions as a viral enterotoxin, causing diarrhea and fluid accumulation without overt tissue damage.
  • This finding identifies SIV SU as the second described viral enterotoxin, with implications for understanding SIV pathogenesis.

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