Immunological characterization of Echinococcus granulosus cyclophilin, an allergen reactive with IgE and IgG4 from patients with cystic echinococcosis

Clin Exp Immunol. 2002 Apr;128(1):124-30. doi: 10.1046/j.1365-2249.2002.01807.x.


By immunological screening of a cDNA library derived from protoscoleces of Echinococcus granulosus with IgE from patients with cystic echinococcosis (CE) and allergic manifestations, we isolated a protein identical to E. granulosus cyclophilin. The protein, named EA21, has close homology with Malassezia furfur cyclophilin allergen (Mal f 6) and with human cyclophilin. Using immunoblotting (IB) with a polyclonal antibody specific to EA21, we identified E. granulosus cyclophilin both in protoscoleces and in sheep hydatid fluid. Of the 58 sera from patients with CE, 29 (50%) were IgE positive to EA21, whereas, despite the high sequence homology, none were IgE positive to Mal f 6 or human cyclophilin. Only 26 of the 58 patients (45%) had IgG specific to EA21, whereas all patients (100%) had IgG specific to Mal f 6 and human cyclophilin. IB analysis showed that serum IgE-binding reactivity to EA21 differed significantly in patients with and without allergic reactions (20 of 25, 80% versus nine of 33, 27%; P < 10(-4)). Conversely, five of the 25 patients who had CE-related allergic manifestations (20%) and 21 of the 33 who did not (63%) had specific IgG4 (P = 10(-3)) and total IgG to EA21. EA21 induced a proliferative response in 15 of 19 (79%) patients' PBMC regardless of the allergic manifestations, but it induced no IL-4 production. Overall, these findings suggest that E. granulosus cyclophilin is a conserved, constitutive, parasite protein that does not cross-react with cyclophilins from other organisms and is involved in the allergic symptoms related to CE.

Publication types

  • Case Reports
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adolescent
  • Adult
  • Aged
  • Allergens / genetics
  • Allergens / immunology*
  • Amino Acid Sequence
  • Animals
  • Antibodies, Helminth / immunology*
  • Antigens, Helminth / genetics
  • Antigens, Helminth / immunology
  • Cells, Cultured
  • Cross Reactions
  • Cyclophilins / genetics
  • Cyclophilins / immunology*
  • Cysts / immunology
  • Echinococcosis / diagnosis
  • Echinococcosis / immunology*
  • Echinococcus / immunology*
  • Female
  • Humans
  • Hypersensitivity, Immediate / immunology
  • Hypersensitivity, Immediate / parasitology
  • Immunoglobulin E / immunology
  • Immunoglobulin G / immunology
  • Lymphocyte Activation
  • Male
  • Middle Aged
  • Molecular Sequence Data
  • Sequence Homology, Amino Acid


  • Allergens
  • Antibodies, Helminth
  • Antigens, Helminth
  • Immunoglobulin G
  • Immunoglobulin E
  • Cyclophilins