Diagnostic evaluation of a synthetic peptide derived from a novel antigen B subunit as related to other available peptides and native antigens used for serology of cystic hydatidosis.
A synthetic peptide (GU4) derived from an antigen B (AgB) subunit was serologically compared with crude antigen (HCFA); immunopurified AgB and antigen 5 (Ag5), and two other synthetic peptides, for diagnosis of human cystic hydatidosis. GU4 was derived from the sequence of AgB/2, the novel AgB subunit described by us. The other two peptides: 65 (AgB mimotope) and 89-122 (Ag5 mimotope), were described by others. Antigens B and 5 showed higher diagnostic sensitivity than corresponding peptides. All sera reacting with peptides 89-122 and GU4 also reacted with 65. The latter provided three to four times higher sensitivity than the former two peptides, but 30% lower specificity. The diagnostic efficiency of AgB (82%) was higher than those of Ag5 (74%) and HCFA (71%). Interestingly, 89-122 only reacted with hydatid sera, some of which did not react with AgB. Considering positive those reacting with 89-122 or AgB, sensitivity increases from 77% (with AgB) to 82% (combined), while specificity is the same as with AgB (86%). Our results suggest that hydatid serology may be improved by: a) combining several defined antigens (including synthetic peptides), b) design of new E. granulosus-specific mimotopes, which react with the false negative sera (16/90; 18%).
Barbieri
M
M
Cátedra de Inmunología, Facultades de Química y Ciencias, Universidad de la República, Montevideo, Uruguay.
Fernández
V
V
González
G
G
Luaces
V M
VM
Nieto
A
A
D000818:Animals; D000909:Antibodies, Helminth / Q000097:blood; D000947:Antigens, Helminth / Q000276:immunology*; D004443:Echinococcosis / Q000175:diagnosis* / Q000276:immunology; D004446:Echinococcus / Q000276:immunology*; D006801:Humans; D010455:Peptides / Q000737:chemistry / Q000276:immunology
D000909:Antibodies, Helminth; D000947:Antigens, Helminth; D010455:Peptides