title: Evolutionary immune response to conserved domains in parasites and aeroallergens.
abstract: The immune response based on immunoglobulin E (IgE) evolved as a defense against specific parasitic infections. In the absence of active helminthic infections, the immune system has redirected its IgE epitopes toward innocuous environmental antigens. Helminths and aeroallergens have  a similar stereotypical IgE response to unique antigens that can not be explained by chance alone. This study was designed to evaluate potential homology between conserved protein domains embedded in parasitic organisms and aeroallergens. Search and retrieval systems for nucleotide and protein  sequences (Entrez, BLAST, and National Center for Biotechnology Information) were searched to identify conserved domains between allergens and certain parasites. A total score was developed that correlated positively with homology between compared sequences. Over 2000 domains were examined.  We found matches with a high total score (>100) that signified a strong positive correlation between sequences in allergens (n = 30) and parasites (n = 13). Multiple shared conserved domains were identified between parasites and allergens. Parasite-allergen combinations with the  most significant homology (greatest total score) were Plasmodium falciparum enolase and Hev b9 (total score, 612), Schistosoma mansoni albumin and Fel d 2 (total score, 991), Ascaris lumbricoides tropomyosin and Ani s3 (total score, 531), and Wuchereria bancrofti  trypsin and Blo t3 (138). Homologous conserved domains exist in specific parasites and allergens, consistent with the theory that the human IgE-eosinophil immune response to common allergens is a direct consequence of stimulation by parasitic organisms.
authors: Department of Medicine, Overlook Hospital, Summit, NJ, USA.
authors: Brett Phillip
authors: BP
authors: Bielory
authors: Timothy
authors: T
authors: Mainardi
authors: Menachem
authors: M
authors: Rottem
mesh_terms: D000485:Allergens / Q000737:chemistry / Q000235:genetics / Q000276:immunology*; D000818:Animals; D000947:Antigens, Helminth / Q000737:chemistry / Q000235:genetics / Q000276:immunology*; D052179:Antigens, Plant / Q000235:genetics / Q000276:immunology; D005075:Biological Evolution; D002415:Cats; D019295:Computational Biology; D017124:Conserved Sequence / Q000235:genetics / Q000276:immunology; D003429:Cross Reactions; D000939:Epitopes / Q000737:chemistry / Q000235:genetics / Q000276:immunology; D006373:Helminthiasis / Q000276:immunology*; D006376:Helminths / Q000276:immunology; D006801:Humans; D006967:Hypersensitivity / Q000276:immunology*; D007109:Immunity; D007073:Immunoglobulin E / Q000276:immunology; D019476:Insect Proteins / Q000235:genetics / Q000276:immunology; D018448:Models, Immunological; D052638:Particulate Matter / Q000276:immunology; D010751:Phosphopyruvate Hydratase / Q000235:genetics / Q000276:immunology; D010944:Plants / Q000276:immunology; D010963:Plasmodium falciparum / Q000276:immunology; D017434:Protein Structure, Tertiary / Q000235:genetics; D017386:Sequence Homology, Amino Acid; D012709:Serum Albumin / Q000235:genetics / Q000276:immunology
chemical_list: D000485:Allergens; D000947:Antigens, Helminth; D052179:Antigens, Plant; D000939:Epitopes; C522889:Fel d 2 allergen, Felis domesticus; D019476:Insect Proteins; D052638:Particulate Matter; D012709:Serum Albumin; D007073:Immunoglobulin E; D010751:Phosphopyruvate Hydratase