Infection of Macaca nemestrina neonates with HIV-1 via different routes of inoculation.
OBJECTIVE
Receptive anal intercourse but not orogenital sex has been identified as a major risk factor for transmission of HIV-1. Recent studies using simian immunodeficiency virus (SIV) in rhesus macaques have demonstrated relatively efficient infection following oral administration, indicating that modes of transmission may vary between HIV-1 and SIV. Here, we investigate whether HIV-1 infection of macaques via the oral route is more efficient than via the rectal route.


METHODS
Eleven Macaca nemestrina neonates were exposed to HIV-1 via different routes (four oral, two intravenous, and five rectal). One animal was orally inoculated with a sham inoculum and two control animals were not exposed.


METHODS
All animals were followed for virological signs of infection, and for pathogenesis associated with HIV-1 infection by general physical examinations, complete blood cell counts and lymphocyte subset analysis, and full necropsies.


RESULTS
Three out of five rectally exposed macaques and both of the intravenously inoculated animals became infected with HIV-1, whereas none of the orally exposed animals showed evidence of HIV-1 infection. Clinical observations following exposure included failure to thrive in the orally inoculated animals and low CD4/CD8 ratios in the rectally exposed macaques.


CONCLUSIONS
The finding that, contrary to what has been reported for SIV, transmission of HIV-1 via the oral route is not more efficient than via the rectal route, indicates important biological differences between HIV-1 and SIV, with direct implications for the spread of HIV and associated AIDS, and for development of anti-HIV-1 vaccines.
Bosch
M L
ML
Department of Pathobiology, University of Washington, Seattle 98195, USA.
Schmidt
A
A
Agy
M B
MB
Kimball
L E
LE
Morton
W R
WR
D000818:Animals; D000831:Animals, Newborn; D016516:CD4-CD8 Ratio; D015496:CD4-Positive T-Lymphocytes; D002460:Cell Line; D004195:Disease Models, Animal; D015658:HIV Infections / Q000276:immunology / Q000635:transmission* / Q000821:virology; D015497:HIV-1 / Q000502:physiology*; D006801:Humans; D016131:Lymphocyte Subsets; D008254:Macaca nemestrina; D009061:Mouth Mucosa; D012007:Rectum