Natural antibodies to interferon-gamma

Area of Science:

• Immunology
• Virology
• Autoimmunity

Background:

• Interferon-gamma (IFN-gamma) is a crucial cytokine in cell-mediated immunity.
• Natural antibodies to IFN-gamma are found in healthy individuals and increase during viral infections.
• The role of these natural antibodies in immune regulation is not fully understood.

Purpose of the Study:

• To investigate the functional activity of natural antibodies to IFN-gamma.
• To determine if these antibodies interfere with IFN-gamma's antiviral, antiproliferative, or immunomodulatory functions.
• To explore the potential therapeutic implications of these antibodies.

Main Methods:

• Detection and titration of natural anti-IFN-gamma antibodies in patient and healthy subject sera.
• Affinity purification of natural anti-IFN-gamma antibodies.
• In vitro assays to assess antibody interference with IFN-gamma's antiviral, antiproliferative, receptor binding, and HLA-DR antigen induction activities.
• Evaluation of antibody effects on mixed lymphocyte cultures and in animal models.

Main Results:

• Natural anti-IFN-gamma antibodies did not inhibit IFN-gamma's antiviral or antiproliferative effects, nor its receptor binding.
• These antibodies inhibited IFN-gamma-induced HLA-DR antigen expression on U937 cells.
• They interfered with lymphocyte proliferation and cytotoxic lymphocyte generation in mixed lymphocyte cultures.
• Animal model experiments suggested a role in limiting immune response intensity and duration.

Conclusions:

• Natural antibodies to IFN-gamma selectively interfere with its immunomodulatory functions, not its direct antiviral or antiproliferative activities.
• These antibodies may play a role in regulating immune responses.
• Targeting these antibodies could offer novel therapeutic strategies for diseases with aberrant cell-mediated immunity.