The immune memory of innate immune systems

Area of Science:

• Immunology
• Vaccinology

Background:

• Immune memory was traditionally attributed solely to adaptive immunity.
• Adaptive immune memory alone does not fully explain vaccine efficacy against non-target pathogens.
• Innate immune system responses can be altered by initial stimuli, suggesting memory formation.

Purpose of the Study:

• To review the concepts of trained immunity and endotoxin tolerance as forms of innate immune memory.
• To discuss the formation of innate immune memory induced by mRNA vaccines.
• To highlight the significance of innate immune memory in future vaccinology.

Main Methods:

• Literature review of trained immunity and endotoxin tolerance.
• Discussion of innate immune memory mechanisms.
• Analysis of mRNA vaccine-induced innate immune memory.

Main Results:

• Trained immunity demonstrates enhanced monocyte responsiveness to heterologous pathogens after BCG vaccination.
• Endotoxin tolerance shows attenuated monocyte responsiveness after initial lipopolysaccharide exposure.
• Innate immune memory formation is a recognized phenomenon distinct from adaptive immunity.

Conclusions:

• Innate immune memory, encompassing trained immunity and endotoxin tolerance, plays a crucial role in host defense.
• mRNA vaccines represent a novel modality for inducing innate immune memory.
• Understanding innate immune memory is vital for developing next-generation vaccines.