Western Australian Research Institute for Child Health, Perth.
Sequence information has been obtained from 5 cDNA clones encoding the major house dust mite allergen Der p I, including one which codes for the full length preproenzyme form of the molecule. All translated sequences were unique with 1-3 differences between each clone. 4/5 of the substitutions found were to residues found in Der f I and two positions had a substitution in more than one clone. The polymorphisms included residues already described to be in T cell epitopes, so as well as being necessary to consider them in the construction of synthetic allergens, the substitutions will be important for the interpretation of experimental and genetic studies.