T-cell line proliferation.

Proliferative responses of Birch pollen (BP)-specific TCLs from BP-allergic donors stimulated with decreasing amounts of LPS-contaminated Bet v 1.0101, mock-Bet v 1.0101 and nitro-Bet v 1.0101 (protein) and stimulated with decreasing amounts of three different LPS-free immunodominant epitopes (peptides) of Bet v 1.0101 containing a tyrosine, in native form or nitrated. The SI was calculated as the ratio between counts per minute (cpm) in stimulated cultures and cpm of the medium control. Each symbol represents a single donor (n = 5), the mean is indicated with a horizontal bar and the SD is represented by the vertical bar. Statistical significance was calculated with One-Way Anova and the Tukey's test per concentration (untreated, mock-nitrated and nitrated protein): P = .2506 for 5 µg/ml protein; P = .1354 for 2.5 µg/ml protein; P = .0815 for 1.25 µg/ml protein and P = .0618 for 0.625 µg/ml protein. Statistical significance was calculated with the t-test for the untreated and nitrated peptide per concentration. No values below P = .0824 could be measured.