524-M.
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Phenotypic and Functional Characterization of Dendritic Cells Generated from Monocytes of HIV-Infected Patients in the Presence of GM-CSF and Interferon-alpha
C. Carbonneil1, L. Weiss Laurence*1, and 2
1INSERM U430 Hosp. Broussais and 2Univ. Pierre et Marie Curie, Paris, France
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Background: We previously demonstrated that DC differentiated from monocytes of HIV-seronegative individuals, in the presence of GM-CSF and IFN-alpha (GM/IFN DC) produced IL-12 and were capable of inducing CD8 response to HIV lipopeptides thus exhibiting functional characteristics of type 1 DC.
Methods: In the present study, we have characterized the phenotype and the function of DC generated from monocytes of HIV-infected patients under the same experimental conditions (GM-CSF:1000UI/mL and IFN-alpha: 500UI/mL for 7 days). GM/IFN DC were compared to control DC generated in the presence of GM-CSF and IL-4. Patients receiving HAART, exhibiting CD4 cell counts above 500/mm3 and plasma HIV-RNA < 50 copies/mL for at least 1 year, and thus potential candidates to therapeutic immunization, were included (n=6).
Results: GM/IFN cells from HIV-infected patients exhibited phenotypic characteristics of DC. Compared to DC generated in the presence of GM-CSF and IL-4, GM/IFN DC were shown to exhibit lower expression of CD1a, CD4, CXCR4, and DC-SIGN. However, CCR5 expression was rather increased. Functionally, those DC produced IL-12 and IL-10 following stimulation by SAC or CD40L, as DC from seronegative donors. In order to study the ability of these cells to induce specific immune responses, we are currently analyzing in ELISPOT assays, IFN-gamma production by CD8+ T lymphocytes after stimulation by GM/IFN DC pulsed with HLA class I relevant HIV lipopeptides.
Conclusions: Our results suggest that GM-CSF/IFN-alpha combination induces the differentiation of monocytes from HIV-infected patients into functional DC. This combination of 2 cytokines, already used in clinical practice, may represent a good option for optimizing immunization conditions for specific immune-based therapy in HIV infection and thus worthy to be assessed in in vivo models.
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