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BACKGROUND: Monocyte-derived-dendritic-cells (MDDC) are the major DC type used in vaccine-based clinical studies for a variety of cancers. In order to assess whether in vitro differentiated MDDC from cryopreserved PBMC of cancer patients are functionally distinct from those of healthy donors, we compared these cells for their expression of co-stimulatory and functional markers. In addition, the effect of cryopreservation of PBMC precursors on the quality of MDDC was also evaluated using samples from healthy donors. METHODS: Using flow cytometry, we compared normal donors and cancer patients MDDC grown in the presence of GM-CSF+IL-4 (immature MDDC), and GM-CSF+IL-4+TNFalpha+IL-1beta+IL-6+PGE-2 (mature MDDC) for (a) surface phenotype such as CD209, CD83 and CD86, (b) intracellular functional markers such as IL-12 and cyclooxygenase-2 (COX-2), (c) ability to secrete IL-8 and IL-12, and (d) ability to stimulate allogeneic and antigen-specific autologous T cells. RESULTS: Cryopreservation of precursors did affect MDDC marker expression, however, only two markers, CD86 and COX-2, were significantly affected. Mature MDDC from healthy donors and cancer patients up-regulated the expression of CD83, CD86, frequencies of IL-12+ and COX-2+ cells, and secretion of IL-8; and down-regulated CD209 expression relative to their immature counterparts. Compared to healthy donors, mature MDDC generated from cancer patients were equivalent in the expression of nearly all the markers studied and importantly, were equivalent in their ability to stimulate allogeneic and antigen-specific T cells in vitro. CONCLUSION: Our data show that cryopreservation of DC precursors does not significantly affect the majority of the MDDC markers, although the trends are towards reduced expression of co-stimulatory makers and cytokines. In addition, monocytes from cryopreserved PBMC of cancer patients can be fully differentiated into mature DC with phenotype and function equivalent to those derived from healthy donors.
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OBJECTIVES: To determine whether immunotherapy of chronic HIV-1 infection can prevent or attenuate viremia upon antiviral discontinuation. DESIGN: This was a Phase II randomized, partially double blinded, 2x2 factorial study of three steps of 12 wk/step. Step I involved four groups: (1) vaccine placebo, (2) vaccine (ALVAC, vCP1452), (3) placebo + interleukin 2 (IL-2), and (4) vaccine + IL-2. Step II involved a 12-wk diagnostic treatment interruption (DTI). Step III involved an extension of the DTI for an additional 12 wk. SETTING: The Weill-Cornell General Clinical Research Center. PARTICIPANTS: Chronically infected HIV-1 positive adults with undetectable HIV-1 levels and > 400 CD4+ T cells/microl. INTERVENTIONS: An HIV canarypox vaccine (vCP1452) and vaccine placebo, administered every 4 wk for four doses, and low-dose IL-2 administered daily for 12-24 wk. OUTCOME MEASURES: Primary endpoints: (1) Proportion of participants with undetectable plasma HIV RNA during trial Step II, (2) mean log10 HIV RNA copies/ml ([HIV]) from weeks 21-25, and (3) proportion of individuals eligible for trial Step III. RESULTS: 44 participants were randomized, but 16 withdrew or were withdrawn before completing Step II. As all participants underwent viral relapse in Step II, the study was terminated after 28 participants completed Step II. Among the four groups, there was no difference in mean [HIV] or the proportion of individuals with < log10 4.48 HIV; no difference between the mean [HIV] of the two groups that received ALVAC (n = 17) versus placebo (n = 11); and no significant difference between the mean [HIV] of the two groups that received IL-2 (n = 11) versus placebo (n = 17). CONCLUSIONS: Neither ALVAC (vCP1452) nor low-dose daily IL-2 nor their combination prevented the relapse of viremia upon discontinuation of antiviral therapy.
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We have developed a flow cytometric method for the detection of intracellular cyclooxygenases (COX) in human whole blood monocytes and a COX-2 inducible human cell line. COX-2 is induced by endotoxin activation of whole blood monocytes or by the addition of fetal bovine serum (FBS) to a serum-deprived human fibroblastoid cell line, CCD-1070Sk. Cells are permeabilized with FACS Lysing Solution (FLS) containing saponin (Sap), stained intracellularly with COX-2 and COX-1 monoclonal antibodies (mAbs) and analyzed flow cytometrically. Intracellular COX-2 is specifically detected in endotoxin-stimulated CD14(+) monocytes in whole blood and in the inducible cell line. The specificity of COX-2 and COX-1 binding is demonstrated by competitive inhibition studies in cells and binding studies on protein-conjugated beads. In addition, a two-color reagent combination is described which simultaneously detects COX-2 and COX-1. We conclude that specific, intracellular COX-1 and COX-2 expression can be readily identified by flow cytometry in whole blood monocytes and cultured cells. The relative rapidity, ease of use and small sample volume required by this assay makes it a suitable methodology for studying COX expression in both preclinical and clinical research settings.
