Chimeric Antigen-LgDNA Nanoparticles Attenuate Airway Th2 Polarization.

Introduction: The therapeutic efficacy for airway allergies needs to be improved. Th2 polarization is a primary pathological feature of airway allergies. We constructed chimeric antigen-LgDNA (Lactobacillus rhamnosus DNA) nanoparticles (CAP-NPs). The effects of CAP-NPs on reconciling airway Th2 polarization were tested.

Methods: In this study, disulfide bond-linked antigen-major histocompatibility complex II (MHC II)-LgDNA nanoparticles (NPs) were constructed and designated CAP-NPs. An airway Th2 polarization mouse model was established to test the effects of CAP-NPs on suppressing the Th2 response.

Results: The CAP-NP components of ovalbumin (OVA), major histocompatibility complex II (MHC II), and LgDNA were confirmed in a series of laboratory tests. The CAP-NPs remained stable at pH7.2 for at least 96 h. In in vitro experiments, CAP-NPs bound to the surface of OVA-specific CD4⁺ T cells, which resulted in apoptosis of the antigen-specific CD4⁺ T cells. Removal of any of the three components from the NPs abolished the induction of apoptosis of antigen specific CD4⁺ T cells. CAP-NPs increased the expression of lysine-specific demethylase 5A (KDM5A) in CD4⁺ T cells. Histone H3K9 and the gene promoter of caspase 8 were demethylated by KDM5A, which led to transcription and expression of the caspase 8 gene. Administration of CAP-NPs significantly alleviated experimental airway Th2 polarization through activating the caspase 8-apoptosis signaling pathway.

Discussion: In this paper, we constructed CAP-NPs that could induce antigen-specific CD4⁺ T cell apoptosis. Administration of CAP-NPs efficiently alleviated experimental airway Th2 polarization.