IgE-binding epitope analysis of Bla g 5,the german cockroach allergen

Cockroach infestations have been linked with allergic diseases such as asthma in humans. bla g 5,sigma class glutathione s-transferase (gst),is the major cockroach allergen which has the highest ige response value of all cockroach allergens. although several cockroach allergens have been identified and cloned,information regarding their b ell and t cell ige-binding epitopes is limited. in order to analyze the ige binding epitopes of bla g 5,full-length and five peptide fragments (a,1-100 amino acid residue; b,91-201; ba,1-125; bb,1-150; bc,1-175) were expressed. twelve (37.5%) of 32 sera from cockroach-sensitized subjects showed positive ige reactivity to the recombinant bla g 5 (rbla g 5). six strong positive sera were selected for the epitope study. recombinant proteins not containing 176-201 amino acid residues were unable to react to sera from cockroach sensitized individuals,suggesting that this region contains the ige-binding epitope. despite strong ige reactivity to rbla g 5,the pooled serum from 5 cockroach-sensitized patients did not show ige reactivity to all synthetic peptides consisting of 15 residues covering 161-201 amino acids. these results suggest the possibility that bla g 5 may have a conformational epitope in the c-terminal region. gst is the important target for the development of vaccines and drugs against allergic diseases because of high cross-reactivity among insect species. this study will aid recombinant allergen research for immunotherapy of cockroach allergens and other insect allergens. © 2010 bentham science publishers ltd.