Oral SIV, SHIV, and HIV type 1 infection

Area of Science:

• Virology
• Immunology
• Infectious Diseases

Background:

• Simian immunodeficiency virus (SIV) and human immunodeficiency virus type 1 (HIV-1) are lentiviruses that cause immunodeficiency.
• Mucosal transmission is a key route for lentivirus infection.
• Understanding SIV oral transmission in macaques provides a model for HIV-1 transmission.

Purpose of the Study:

• To investigate the efficiency of SIV oral mucosal transmission in rhesus macaques.
• To determine if intact mucosal surfaces are a barrier to oral SIV infection.
• To assess the implications for HIV-1 transmission.

Main Methods:

• Oral inoculation of adult and neonatal rhesus macaques with various SIV and SHIV strains (cell-free and infected whole blood).
• Assessment of viremia and disease development post-inoculation.
• Comparison of oral versus rectal routes for SIV entry efficiency.

Main Results:

• SIV strains, including uncloned and molecularly cloned, successfully crossed intact oral mucosal surfaces in both adult and neonatal macaques.
• Oral inoculation with cell-free SIV and infected whole blood led to systemic infection and disease.
• Neonatal macaques were persistently infected after oral exposure to a chimeric SHIV strain.
• The oral route was more efficient than the rectal route for SIV entry in adult macaques after non-traumatic inoculation.

Conclusions:

• Intact oral mucosal surfaces are permissive to SIV infection.
• Oral exposure to various SIV strains, including T-cell tropic variants, can lead to systemic infection and disease.
• The efficiency of oral SIV transmission has significant implications for understanding HIV-1 transmission during oral-genital contact.