Molecular mechanisms of autoimmunity

Area of Science:

• Immunology
• Molecular Biology
• Genetics

Background:

• Autoimmunity involves diverse molecular and cellular mechanisms.
• Genetic factors, such as specific alleles controlling antigen presentation, are crucial for T cell recognition and autoimmune predisposition.
• Infections can trigger autoimmunity through molecular mimicry, where pathogen epitopes resemble host proteins, leading to cross-reactive autoantibodies.

Purpose of the Study:

• To elucidate the multifaceted mechanisms underlying autoimmune responses.
• To explore the role of genetic factors and protein alterations in the development of autoimmunity.
• To understand the contribution of natural and pathogenic autoantibodies in autoimmune diseases.

Main Methods:

• Review of molecular and cellular events in autoimmunity.
• Analysis of genetic predispositions, including specific gene alleles (e.g., CTLA-4, PTPN22, FOXP3).
• Examination of protein alterations (mutations, posttranslational modifications, misfolding) and their immunogenicity.
• Investigation of sequestered antigens and regulatory protein disruptions.
• Characterization of natural autoantibodies and their role in generating pathogenic autoantibodies.

Main Results:

• Autoimmune responses are initiated by genetic susceptibility, molecular mimicry following infection, or alterations in self-proteins.
• Altered self-proteins, including those with mutations, posttranslational modifications, or misfolding, can elicit autoimmune reactions.
• Disruptions in regulatory proteins, such as CTLA-4, PTPN22, and FOXP3, are linked to increased autoimmune disease risk.
• Sequestered antigens, once exposed, become targets of immune responses.
• Natural autoantibodies can serve as precursors for high-affinity pathogenic autoantibodies through somatic hypermutation and class switch recombination.

Conclusions:

• Autoimmunity results from a complex interplay of genetic predisposition, environmental factors like infections, and alterations in self-proteins.
• Genetic variations in key immune regulatory genes significantly influence susceptibility to autoimmune diseases.
• The immune system's response to altered or exposed self-antigens, alongside the evolution of natural autoantibodies, are critical pathways in the pathogenesis of autoimmunity.