ABSTRACT
Cytokines, such as interferons (IFN), underlie many immunological functions and are increasingly implicated in disease-related symptoms and pathology. In order to study the potential roles of IFN alpha and its antagonists in autoimmune phenomena, the sera from 89 patients (aged 15-95 years, 65 females) diagnosed as having myasthenia gravis (MG) (2 months to 34 years duration) were tested for the presence of natural anti-IFN alpha-2b auto-antibodies. Sera were screened for anti-IFN alpha-2b by a sandwich-type enzyme immunoassay system. Ten (11.2%) and 6 (6.7%) sera were identified that contained positive-competing and non-competing anti-IFN alpha-2b auto-antibodies, respectively. The MG sera were further analyzed by immunobloting against reduced IFN alpha-2b and for neutralizing anti-IFN alpha activity in an antiviral assay cells system. From tested EIA positive-competing sera, 5 were shown to be positive by immunoblot and 6 sera were found to contain neutralizing anti-IFN alpha-2b. Four of the 6 neutralizing anti-IFN alpha-2b sera came from patients with thymoma-associated MG. The sera were studied for linear epitope recognition on the IFN alpha-2b molecule by a solid phase binding assay, in which overlapping peptides homologous with the entire IFN alpha-2b sequence were separately synthesized on a nitrocellulose sheet. Peptides number 2 (residues 8-21), 3 (15-28), 6 (33-46), 10 (63-76), 15 (98-112), and 21 (141-154) were immunoreactive. Peptide 21 was apparently associated with antiviral activity, although peptide 21 has not been previously described as an immunogenic determinant on the IFN alpha-2b molecule. These results indicate that neutralizing anti-IFN alpha-2b is often present in MG, particularly in cases of thymoma-associated MG, and recognize a variety of epitopes on the IFN alpha-2b molecule, including those involved in its biological activity. Two groups of IFN epitopes were described associated with patient's age but not with diseases evolution.
Subject(s)
Antibodies/immunology , Epitope Mapping , Epitopes/immunology , Interferon-alpha/immunology , Myasthenia Gravis/immunology , Adult , Age Factors , Aged , Aged, 80 and over , Female , Humans , Immunoblotting , Male , Middle Aged , Time FactorsABSTRACT
Se analizó la influencia ejercida por varios factores en la inmunogenicidad del IFNa-ab humano recombinante (Herberon Alfa R) en ratones. Estos fueron: Frecuencia y vía de administración, presencia de albúmina sérica humana (HSA) como excipiente en la formulación y genotipo del complejo mayor de histocompatibilidad (MHC). La presencia de anticuarpos anti IFNa en sueros se detectó por un sistema ELISA tipo "sandwich". Los ratones inmunizados con 100 000 UI de IFNa-2b tres veces por semana produjeron títulos elevados de anticuerpos más rápidamente que los inyectados con 300 000 UI una vez por semana. Los títulos fueron mayores cuando el IFN se administró por vía intraperitoneal, comparados con la subcutánea, intravenosa e intramuscular(AU)
