IgA expression correlated with the suppressive capacity in the IgG-negative fractions of EN.

Abstract

<p>Freshly isolated granulocytes from healthy blood donors (n = 9) were stimulated with IL-3 (2 ng/ml), anti-IgE (25 ng/ml) and Brugia antigen extracts (10 μg/ml) alone or in the presence of 5 μg/ml of IgG negative fractions of EN. Cells were stained with anti-CD63 and HLADR antibodies. Activated granulocytes were characterized as CD63+/HLADR- cells and the percentage of inhibition was calculated using the control without plasma as 100% of activation (0% of inhibition). The percentage of inhibition was then correlated with the expression of IgE, IgM and IgA determined by Luminex assay. Each dot represents the plot of the expression of IgE (A), IgM (B) or IgA (C) to the corresponding value of the inhibition. Thereafter, the percentage of activated granulocytes (CD63+/HLADR- cells) was determined after 18 hours of incubation (D) in the presence of IgE/IL-3 alone (dark bar) or in combination with either bulk plasma from EN (EN), IgA negative fractions (EN) IgA- or IgA positive fractions (EN) IgA+. Bars represent means ± SEM of the percentage of activated granulocyte CD63⁺/HLADR^- cells. Statistical comparison was based on Spearman’s rank correlation (A-C) or Kruskal-Wallis one-way ANOVA followed by Dunn post-hoc test (D). The indicated p-values refer to the significance level among all groups and asterisks indicate the level of significance, determined by Dunn’s multiple comparisons test; *: p<0.05; **: p<0.01. Graphs are representative of 3 independent experiments.</p