Yb. Dayan et al., PODOCARPUS-GRACILIOR AND CALLITRIS-VERRUCOSA - NEWLY IDENTIFIED ALLERGENS THAT CROSS-REACT WITH CUPRESSUS-SEMPERVIRENS, Clinical and experimental allergy, 25(5), 1995, pp. 456-460
Thirty-six symptomatic patients, with positive skin reactions to Cupre
ssus sempervirens pollen extract were skin-tested with pollen extracts
of Podocarpus gracilior and Callitris verrucosa, of these 17 (47%) ha
d positive responses to P. gracilior, nine (25%) to C. verrucosa, and
six (17%) to both. None of the non-atopic healthy controls had positiv
e reactions to either of the extracts. Radioallergosorbent test (RAST)
-inhibition studies were performed with pooled sera from three patient
s. Fifty per cent inhibition was obtained with 11 mu g protein of C. s
empervirens, 54 mu g of P. gracilior, and 71 mu g of C. verrucosa; how
ever, when pollen extract of Olea europaea, an unrelated allergen, was
tested, 265 mu g protein were needed to obtain 50% inhibition. One-di
mension sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS
-PAGE) analysis of pollen extracts from the three species revealed tha
t they had several very similar protein bands. Using Western blot anal
ysis, several closely related IgE binding proteins were identified in
the three species. It was concluded that the pollen grains of P. graci
lior and of C. verrucosa are potentially allergenic. The presence of c
ommon allergenic proteins indicate partial crossreactivity with C. sem
pervirens.