Gas Plasma Protein Oxidation Increases Immunogenicity and Human Antigen-Presenting Cell Maturation and Activation

Abstract

Protein vaccines rely on eliciting immune responses. Inflammation is a prerequisite for immune responses to control infection and cancer but is also associated with disease onset. Reactive oxygen species (ROSs) are central during inflammation and are capable of inducing non-enzymatic oxidative protein modifications (oxMods) associated with chronic disease, which alter the functionality or immunogenicity of proteins that are relevant in cancer immunotherapy. Specifically, antigen-presenting cells (APCs) take up and degrade extracellular native and oxidized proteins to induce adaptive immune responses. However, it is less clear how oxMods alter the protein’s immunogenicity, especially in inflammation-related short-lived reactive species. Gas plasma technology simultaneously generates a multitude of ROSs to modify protein antigens in a targeted and controlled manner to study the immunogenicity of oxMods. As model proteins relevant to chronic inflammation and cancer, we used gas plasma-treated insulin and CXCL8. We added those native or oxidized proteins to human THP-1 monocytes or primary monocyte-derived cells (moDCs). Both oxidized proteins caused concentration-independent maturation phenotype alterations in moDCs and THP-1 cells concerning surface marker expression and chemokine and cytokine secretion profiles. Interestingly, concentration-matched H2O2-treated proteins did not recapitulate the effects of gas plasma, suggesting sufficiently short diffusion distances for the short-lived reactive species to modify proteins. Our data provide evidence of dendric cell maturation and activation upon exposure to gas plasma- but not H2O2-modified model proteins. The biological consequences of these findings need to be elucidated in future inflammation and cancer disease models.

Medical Gas Plasma Technology Combines with Antimelanoma Therapies and Promotes Immune‐Checkpoint Therapy Responses

“…[ 72 ] Functional analysis of APCs after challenging with plasma‐oxidized tumor cells increased phagocyte activation, [ 73 ] followed by enhanced tumor material uptake [ 74 ] as seen in our study and interaction with T cells. [ 69 ] Moreover, a recent screening on a protein library pointed out to an inherent DAMP activity of oxidatively modified proteins generated by plasma treatment [ 75 , 76 ] comparable to advanced glycosylation end‐products on naturally occurring carbohydrates. [ 77 ] Following successful cross‐presentation and T cell priming, an inhospitable TME may preclude proper function of the expanded T cell repertoire.…”