Reactivity and sensitivity of mast cell degranulation and
Prostaglandin D2 synthesis increase with increasing
affinity of IgE for allergen.
Mast cell reactivity was threefold higher with high affinity IgE clones
(65%; IQR = 47 – 80) than with low affinity clones (20%; IQR = 12 –
25, p=0.0081) (figure 1A). Mast cell sensitivity (EC50)
decreased 12.850-fold from 0.07 pg/ml (IQR = 0.02 – 7.2) Der p 2
allergen with high affinity clones to 900 pg/ml (IQR = 0.3 – 1.1) Der p
2 allergen when low affinity clones were used for sensitization
(p=0.0395). Release of prostaglandin D2 assessed at 0, 3, 6 and 24 hours
by EIA developed with significance for time (p<0.007) and
affinity (p=0.0437) compared with baseline (n=3, Figure 1B). The release
of PGD2 and its metabolites PGJ2,
delta-12-PGJ2 and
15-deoxy-delta-12,14-PGJ2 was validated by mass
spectrometry in a separate cell line (Figure 1, c-f). Four-fold more
PGD2 was synthesized with high affinity IgE than with
low affinity IgE activation after 3 (p=0.0024) and 6 (p=0.0188) hours
(n=4).