title: Cockroach allergens and asthma in Brazil: identification of tropomyosin as a major allergen with potential cross-reactivity with mite and shrimp allergens.
abstract: BACKGROUND
  Cockroaches produce several proteins that induce IgE antibody responses. Although cockroaches are abundant in warm and humid areas, sensitization to cockroach allergens has not been investigated in Brazil.
  
  
  OBJECTIVE
  The aims of this study were to investigate the frequency of cockroach allergy among patients with asthma, rhinitis, or both in Brazil and to identify American cockroach allergens.
  
  
  METHODS
  Skin tests using cockroach extracts were performed on children and young adults with asthma, rhinitis, or both. A Periplaneta americana complementary (c)DNA library was screened by using IgE antibodies from Brazilian patients allergic to cockroaches. Reactivity of an mAb directed to Dermatophagoides pteronyssinus tropomyosin against cockroach tissue was examined by immunofluorescence.
  
  
  RESULTS
  Cockroach allergy was present in 55% and 79% of the patients, as determined by using skin prick tests alone or combined prick and intradermal tests, respectively. Five cDNA clones reacted with IgE antibody and contained the same sequence. A representative clone (1300 bp), pa 12, coded for a protein that reacted with 50% of the sera from patients allergic to cockroaches on plaque immunoassay and showed a high degree of homology to tropomyosins, particularly those from invertebrates. P americana tropomyosin showed 80%, 81%, and 82% sequence identity to tropomyosins from D pteronyssinus, D farinae, and shrimp, respectively, which have been previously defined as important allergens. An mAb directed against D pteronyssinus tropomyosin, which also recognizes shrimp tropomyosin, showed binding to cockroach striated muscle.
  
  
  CONCLUSIONS
  Our results support the recommendation that cockroach extracts should be routinely used for the evaluation of patients with asthma, rhinitis, or both in Brazil. The identification of P americana tropomyosin as an important allergen will make it possible to investigate cross-reactivity among cockroaches, mites, and food derived from invertebrates.
authors.affiliation: Department of Immunology, School of Medicine of Ribeirão Preto-USP, Ribeirão Preto, SP, Brazil.
authors.forename: A B
authors.initials: AB
authors.lastname: Santos
authors.forename: M D
authors.initials: MD
authors.lastname: Chapman
authors.forename: R C
authors.initials: RC
authors.lastname: Aalberse
authors.forename: L D
authors.initials: LD
authors.lastname: Vailes
authors.forename: V P
authors.initials: VP
authors.lastname: Ferriani
authors.forename: C
authors.initials: C
authors.lastname: Oliver
authors.forename: M C
authors.initials: MC
authors.lastname: Rizzo
authors.forename: C K
authors.initials: CK
authors.lastname: Naspitz
authors.forename: L K
authors.initials: LK
authors.lastname: Arruda
mesh_terms: D000293:Adolescent; D000485:Allergens / Q000737:chemistry / Q000276:immunology*; D000595:Amino Acid Sequence; D000818:Animals; D000917:Antibody Formation / Q000502:physiology; D000918:Antibody Specificity; D052179:Antigens, Plant; D001249:Asthma / Q000097:blood / Q000453:epidemiology / Q000276:immunology*; D001483:Base Sequence; D001938:Brazil / Q000453:epidemiology; D002648:Child; D002675:Child, Preschool; D003001:Cloning, Molecular; D003058:Cockroaches; D003429:Cross Reactions / Q000276:immunology; D018076:DNA, Complementary / Q000235:genetics; D033364:Decapoda / Q000276:immunology; D006801:Humans; D007114:Immunization; D015151:Immunoblotting; D007073:Immunoglobulin E / Q000097:blood / Q000276:immunology; D008925:Mites / Q000276:immunology; D008969:Molecular Sequence Data; D011852:Radioallergosorbent Test; D012220:Rhinitis / Q000097:blood / Q000276:immunology; D017386:Sequence Homology, Amino Acid; D012689:Sequence Homology, Nucleic Acid; D014335:Tropomyosin / Q000276:immunology*
chemical_list: D000485:Allergens; D052179:Antigens, Plant; D018076:DNA, Complementary; D014335:Tropomyosin; C105482:allergen Bla g 1; D007073:Immunoglobulin E