Autolytic Mycobacterium leprae Hsp65 fragments may act as biological markers for autoimmune diseases

Area of Science:

• Immunology
• Biochemistry
• Molecular Biology

Background:

• Heat Shock Proteins (Hsp60) are implicated in autoimmune diseases and chronic inflammation.
• The proteolytic activity and stability of recombinant Mycobacterium leprae Heat Shock Protein of 65 kDa (rHsp65) were not fully understood.
• rHsp65 fragments may influence immune responses relevant to autoimmune conditions.

Purpose of the Study:

• To investigate the proteolytic activity and stability of rHsp65.
• To characterize peptides generated from rHsp65 autolysis.
• To evaluate the in vivo immunomodulatory effects of rHsp65 peptides in a mouse model of Systemic Lupus Erythematosus (SLE).

Main Methods:

• Proteolytic activity assay of rHsp65.
• Peptide purification and mass spectrometry analysis.
• In vivo study using (NZB/NZW)F(1) mice model of SLE, assessing antibody titers and survival.

Main Results:

• rHsp65 exhibits significant autolytic instability, fragmenting from the C-terminus to the N-terminus, yielding a stable middle fragment.
• Urea inhibited autolysis, while EDTA enhanced it, suggesting a requirement for metal ions.
• rHsp65 peptides induced a T(H)1-oriented immune response and reduced survival time variance in SLE model mice.

Conclusions:

• rHsp65 undergoes autolysis, generating peptides with immunomodulatory potential.
• Environmental factors may influence Heat Shock Protein stability and contribute to autoimmune processes.
• rHsp65 peptides demonstrate a capacity to modulate immune responses in an autoimmune setting.