from Helicobacter pylori; induced by contact with epithelium; iceA1 has significant sequence homology of about 56% to nlaIIIR, encoding an endonuclease in Neisseria lactamica, but the similarity at the protein level is limited; ICEA1 is speculated to be associated with peptic ulcer disease and may have endonuclease activity; has been sequenced; GenBank AF459446