After selleck compound 30 min of incubation at room temperature, the cells were washed and IL-10 secretion was assessed by flow cytometry. The PBMC isolated from 20 ml heparinized blood were resuspended in 2 ml RPMI-1640 and 800 μl of this suspension were then depleted for monocytes in two steps, involving the addition of 25 μl anti-CD14-coated Dynabeads (Dynal A/S, Oslo, Norway) at 4°, placement in a magnetic particle concentrator (at 4°) for 1 min (Dynal A/S), removal of the free cell suspension
in cold RPMI-1640 and repetition of the whole procedure. T-cell depletion of a further 800 μl of the cell suspension was performed in a similar manner, but with only a single depletion step using 50 μl anti-CD3-coated Dynabeads (Dynal A/S). A 25-μl sample of each preparation, as well as of the remaining untreated cells, was transferred to TruCount tubes (BD Bioscience) and labelled with PE-anti-CD4 and PerCP-anti-CD14 for quantification of the individual cell populations by flow cytometry. Following the depletion procedures, the cell preparations were plated out in microtitre plates,
at 2.5 × 105 cells per well, in RPMI-1640 containing 30% autologous serum. For testing the significance of the normally distributed proliferative response to the various antigens the Student’s paired t-test was applied. The donors exhibited heterogeneous cytokine responses to TG so non-parametric statistics were used learn more for presentation of the data displayed in Fig. 2. However, division of the donor panel into high-TG and low-TG responders rendered the data normally distributed, so non-paired two-sample
t-tests were applied when comparing the effect of antigen stimulation on the Florfenicol cytokine production by different antigens (as depicted in Fig. 3). P-values of < 0·05 were considered significant. The software employed was prism® (GraphPad, San Diego, CA). First, we wished to establish whether the proliferation kinetics of TG-reactive CD4+ T cells resembled those of a primary, or a secondary, immune response. Using the internal marker CFSE to track cell division, CD4+ T-cell proliferation, upon challenge with KLH, was first observed at day 7 (mean ± SEM = 7 ± 4% dividing cells) rising to a level of 27 ± 5% dividing cells at day 9 (Fig. 1). The TT induced more rapid proliferation, being first observable on day 5 (11 ± 3%), peaking at day 7 (26 ± 5%) and subsequently declining (19 ± 7% at day 9), presumably as the result of activation-induced apoptosis.14 The TG-elicited CD4+ T-cell proliferation resembled the TT-induced response, in that cell division was observed at day 5 (15 ± 3%), peaked at day 7 (49 ± 6%), and subsequently declined to 39 ± 6% by day 9 (Fig. 1). The number of dividing T cells in the non-stimulated cell samples never exceeded 4%.