Sequencing Analysis of cDNA Clones Encoding the American Cockroach Cr-PI Allergens

Abstract

This study presents the nuclcotide and deduced amino acid sequences of lour cDNA clones expressing the American cockroach (ACR) Cr-PI allergens rccogm/cd both human alopic IgE antibodies and anti-Cr-PI monoclonal antibodies. Clones C12, C20, C13 and C28 encode proteins of 685, 635, 465, and 392 umino acids with 1, 2. 2 and no potential N-glycosylalion sites, respectively. The predicted molecular weights for C12, C20, C13 and C28 cloned proteins arc 79, 76, 56 and 47 kDa with PI of 6.3, 6.8, 7.3 and 6.6, respectively. In contrast to the CI2 gene, the C20, C13 and C28 genes lack sequences coding for a signal pcptidc, and a high degree of identity (68-95%), including several overlapped predicted antigcnic sites, was found among these allergens. Rccombmant allergens of C12, C13, C20 and C28 showed 45.8%', 20.8'7r, 41.77,- and 83.37, skin rcacti\ ilies, respectively on 24 ACR-scnsitivc patients. Unexpectedly, while no sequence similarities were found to other known allergens, these aromatic amino acid-rich allergens were found to have a striking sequence identity to insect storage proteins (20-37%), insect juvenile hormoncsupprcssible proteins (29-367,) and arthropod hcmocyanins (29-357,). Results suggested that these major ACR allergens are ancestral related to these insect hcmolymph proteins and represent a nesv group of proteins in hcmocyanin supcrfamily. These data will now facilitate epitope mapping studies, and the recombinam allergens mav be valuable for diagnostic and therapeutic purposes.