1999 Volume 65 Issue 4 Pages 592-595
Allergens from five species of shellfishes (oyster Crassostrea gigas, scallop Patinopecten yessoensis, short-neck clam Tapes japonica, turban shell Turbo cornutus, and whelk Neptunea arthritica) were immunologically compared by competitive ELISA inhibition analyses. The cross-reactivity was recognized between shellfish allergens and Crag 1, the oyster allergen, suggesting that, irrespective of species, the major allergen in shellfishes is tropomyosin. When four synthesized overlapping peptides (P-1, LNRRIQLLEEDM; P-2, RIQLLEEDMERS; P-3, LLEEDMERSEER; P-4, EDMERSEERLQT), which comprehend a part of the sequence of K21 d (IgE-binding epitope proposed for Crag 1, IQLLEEDMERSEER), were subjected to competitive ELISA inhibition experiments, only P-3 inhibited the binding of Crag I to specific IgE antibodies in the sensitized serum. Comparison of the sequence of K21d with those of the four synthesized peptides revealed that both N- and C- terminal regions of K21d are essential for the binding to specific IgE antibodies. In addition, P-3 inhibited the binding of specific IgE antibodies to scallop and whelk allergens as well as oyster allergens, but substantially not to those from the other two species. It was thus concluded that shellfish allergens do not always have IgE-binding epitopes in the same regions, although they are all thought to be tropomyosins.
