Variation in Virulence in HIV Pathogens

1
Variation in Virulence in HIV Pathogens

• Colleen Leonard

2
PBj14 isolate of simian immunodeficiency virus
from sooty mangabey monkeys

• Is the most acutely pathogenic primate lentivirus
• Causes fatal diseases within 8 days
• Lethal HIV variants may exist with properties
  similar to those of SIVsmm-PBj
• Spread and subsequent acute lethality of such a
  variant could be suppressed by previous infection
  with less acute variants.

3
Vaccine protection against HIV and related SIV

• This is proving to be a difficult task due to
• Infection with HIV or SIV is fatal most of the
  time despite a strong host immune response to the
  virus
• This ineffective natural immune response suggests
  a vaccine needs to have stringent protective
  immunity to achieve protection
• Live attenuated HIV-1 may be most potent vaccine
  for prevention of AIDS
• Safety concerns is key issue in development

4
Further evidence of differences in virulence in
HIV-1

• Six patients infected by a single infected blood
  donor remained clinically free of symptoms for up
  to 10 years
• Progression to AIDS was lower among 6 subjects
  than 101 other HIV infected transfusion
  recipients
• Findings suggest the 1st subjects were infected
  with a less virulent strain
• Identification of other similar groups can
  provide information on immunpathogensis of HIV-1
  disease that may help the development of a vaccine

5
Conclusion

• Variants of HIV and SIV can differ in virulence
  and the type of disease they produce
• the scope for viral variation in humans is
  enormous
• Novel HIV variants may emerge in the future