Innate Memory Reprogramming by Gold Nanoparticles Depends on the Microbial Agents That Induce Memory.

Area of Science:

• Immunology
• Nanotechnology
• Innate Immunity

Background:

• Innate immune memory enhances protective responses to secondary challenges.
• Engineered nanoparticles, like gold nanoparticles (AuNPs), may influence innate memory due to their inflammatory potential.
• Understanding AuNPs' impact on innate memory is crucial for biomedical applications.

Purpose of the Study:

• To evaluate AuNPs' capacity to induce innate immune memory.
• To investigate AuNPs' ability to modulate existing memory responses induced by microbial agents.
• To explore how AuNPs interact with various microbial stimuli (soluble vs. particulate, whole organisms).

Main Methods:

• Human primary monocytes were exposed to microbial agents with or without AuNPs (primary response).
• Cells were rested, then challenged with lipopolysaccharide (LPS) to assess secondary memory response.
• Production of cytokines like TNFα and IL-10 was measured to evaluate inflammatory and anti-inflammatory profiles.

Main Results:

• AuNPs did not induce memory responses or affect responses to soluble microbial stimuli (MDP, β-glucan).
• AuNPs partially reduced primary responses to whole microorganisms but did not induce memory.
• AuNPs modulated stimulus-induced memory: exacerbating MDP-induced tolerance and downregulating H. pylori-induced tolerance.

Conclusions:

• AuNPs do not induce innate immune memory but can modulate it in a stimulus-specific manner.
• The effects of AuNPs on innate memory are complex and depend on the nature of the microbial agent.
• Significant donor-to-donor variability suggests individual exposure history influences innate memory and nanoparticle reactivity.