Immunological characterization of Echinococcus granulosus cyclophilin, an allergen reactive with IgE and IgG4 from patients with cystic echinococcosis.
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.
Ortona
E
E
Department of Immunology, Istituto Superiore di Sanità, Rome, Italy.
Vaccari
S
S
Margutti
P
P
Delunardo
F
F
Rigano
R
R
Profumo
E
E
Buttari
B
B
Rasool
O
O
Teggi
A
A
Siracusano
A
A
D000293:Adolescent; D000328:Adult; D000368:Aged; D000485:Allergens / Q000235:genetics / Q000276:immunology*; D000595:Amino Acid Sequence; D000818:Animals; D000909:Antibodies, Helminth / Q000276:immunology*; D000947:Antigens, Helminth / Q000235:genetics / Q000276:immunology; D002478:Cells, Cultured; D003429:Cross Reactions; D021983:Cyclophilins / Q000235:genetics / Q000276:immunology*; D003560:Cysts / Q000276:immunology; D004443:Echinococcosis / Q000175:diagnosis / Q000276:immunology*; D004446:Echinococcus / Q000276:immunology*; D005260:Female; D006801:Humans; D006969:Hypersensitivity, Immediate / Q000276:immunology / Q000469:parasitology; D007073:Immunoglobulin E / Q000276:immunology; D007074:Immunoglobulin G / Q000276:immunology; D008213:Lymphocyte Activation; D008297:Male; D008875:Middle Aged; D008969:Molecular Sequence Data; D017386:Sequence Homology, Amino Acid
D000485:Allergens; D000909:Antibodies, Helminth; D000947:Antigens, Helminth; D007074:Immunoglobulin G; D007073:Immunoglobulin E; D021983:Cyclophilins