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Session 46 Poster Presentations
DC-SIGN and Related Molecules
Session Day and Time: Thursday 1:30 - 3:30 pm
Room: Hall D


365
Variations of Dendritic Cells Subsets, NK Cells Proportions and Functions in the First Days of Rectal SIV Infection
K. Petitprez*1, S. Kahi1, A. Couedel-Courteille2, P. Lebon3, A. Hosmalin1, C. Butor1,2
1Cochin Inst, Paris, France; 2Paris 7 Univ, France; and 3St Vincent de Paul Hosp, Paris, France

Background: Dendritic cells (DC) are absolutely required to activate naive T-cells and play a role in antiviral innate immunity by secreting type I interferon (IFN). A cross-talk between DC and resting NK cells may also contribute to the innate defense during viral infections. Two (2) major populations of DC are found in the blood: myeloid CD11c+ DC, which secrete IL-12, and plasmacytoid CD123+ (IL-3-R) DC, which secrete IFN. We found that circulating DC numbers were dramatically decreased in HIV patients (pts) during primary infection (26-57 days post-infection, p.i.). Here we quantified DC, lymphocytes and NK cells populations in the very first days of rectal SIV infection in rhesus macaques.
Methods: Sixteen (16) rhesus monkeys infected by the rectal route with 10 or 100 AID50 SIVmac 251 were compared with 10 healthy animals. DC, lymphocytes, and NK cells populations were quantified in blood samples from 16 hrs to 11 days p.i. using flow cytometric analysis. Type I IFN and IL-12 were tested in the sera.
Results: The proportion of myeloid DC among peripheral blood mononuclear cells was significantly decreased as early as 24 hrs p.i. in the SIV infected monkeys compared to the healthy animals (p = 0.005). The proportion of plasmacytoid DC was also decreased between 16-48 hours p.i. (p = 0.03). In contrast, the proportion of NK cells characterized as CD3- / CD56+ events, was significantly increased as compared to NK cells from healthy macaques (p = 0.03). Concomitantly NK cell cytolytic activity against K562 cells was increased. IFN was found in the sera from day 7 p.i. and IL-12 concentration was significantly increased after day 3 p.i.
Conclusion: We demonstrate for the first time that peripheral blood DC are decreased and NK cell number and activity are increased in the first days of post rectal SIV infection, a good animal model for sexual transmission of HIV.