Physiological-range temperature changes modulate cognate antigen processing and presentation mediated by lipid...

Area of Science:

• Immunology
• Cell Biology
• Biochemistry

Background:

• B cell receptor (BCR) signaling is crucial for initiating humoral immune responses.
• BCR-mediated antigen (Ag) processing and presentation depend on ubiquitination and trafficking of Ag-BCR complexes.
• These complexes are localized to plasma membrane lipid rafts, which are sensitive to temperature.

Purpose of the Study:

• To investigate the impact of physiological-range temperature changes (PRTCs) on BCR functions.
• To determine how temperature affects lipid raft-dependent and -independent BCR activities.
• To elucidate the role of temperature in BCR-mediated antigen processing and presentation.

Main Methods:

• Biochemical analysis of ubiquitinated Ag-BCR complexes.
• Investigation of BCR internalization kinetics at different temperatures (33-39°C).
• Assessment of BCR signaling, ubiquitination, and antigen processing under varying temperature conditions.

Main Results:

• BCR ubiquitination and signaling are significantly affected by PRTCs, primarily within lipid rafts.
• Higher temperatures (37-39°C) increase the extent and duration of Ag-BCR ubiquitination compared to lower temperatures (33°C).
• Elevated temperatures accelerate Ag-BCR degradation and enhance the presentation of peptide-MHC class II complexes from cognate antigen, while fluid-phase antigen processing remains unaffected.

Conclusions:

• PRTCs modulate multiple lipid raft-dependent BCR functions, including antigen processing and presentation.
• Increased temperatures, such as fever, can enhance BCR-mediated antigen processing and presentation kinetics.
• These findings suggest a mechanism by which fever may influence the initiation and maturation of humoral immune responses.