Detection of Human Toxoplasma-Specific Immunoglobulins A, M, and G with a Recombinant Toxoplasma gondii Rop2 Protein

MARTÍN VALENTINA; ARCAVI MIRIAM; SANTILLAN GRACIELA; AMENDOEIRA REGINA; DE SOUZA NEVES ELIZABETH; GRIEMBERG GLORIA; GUARNERA EDUDARDO; GARBERI JUAN; ANGEL SERGIO O

CLINICAL AND VACCINE IMMUNOLOGY

Año: 1998 vol. 5 p. 627 - 631

1556-6811

The Toxoplasma gondii rhoptry protein Rop2 was expressed in Escherichia coli as a fusion protein containing44 kDa of the 55-kDa mature Rop2, supplied with six histidyl residues at the N-terminal end (Rop2196?561).Humoral response during Toxoplasma infection of humans was analyzed by immunoglobulin G (IgG), IgA, andIgM enzyme-linked immunosorbent assay with Rop2196?561 as the antigen substrate. The analyzed sera weredivided according to T. gondii-specific serological tests (IgG, IgA, or IgM indirect immunofluorescence and IgAor IgM immunosorbent agglutination assay) as group A (IgG1 IgA2 IgM2; n 5 35), group B (IgG1 IgA1IgM1; n 5 21), group C (IgG1 IgA1 IgM2; n 5 5), and group D (IgG1 IgA2 IgM1; n 5 16). Twenty-sixT. gondii-seronegative sera from individuals with other infections were also included (group E). Anti-Rop2 IgGantibodies were detected in 82.8% of group A sera and in 97.6% of the sera with acute-phase markerimmunoglobulins (groups B, C, and D). The percentage of IgA antibody reactivity against Rop2196?561 was17.1% in group A, 50% in group D, and 80.8% in groups B and C. The percentage of IgM antibody reactivitywas 0% in groups A and C and 62% in groups B and D. Sera from group E failed to show IgA, IgM, or IgGantibody reactivity. Since T. gondii Rop2 elicits a strong humoral response from an early stage of infection, itis suggested that recombinant Rop2196?561 would be suitable for use in diagnostic systems, in combination withother T. gondii antigens, to detect specific IgG, IgA, and IgM antibodies.