Highly tailorable gellan gum nanoparticles as a platform for the development of T cell activator systems

Abstract

Background T cell priming has been shown to be a powerful immunotherapeutic approach for cancer treatment in terms of efficacy and relatively weak side effects. Systems that optimize the stimulation of T cells to improve therapeutic efficacy are therefore in constant demand. A way to achieve this is through artificial antigen presenting cells that are complexes between vehicles and key molecules that target relevant T cell subpopulations, eliciting antigen-specific T cell priming. In such T cell activator systems, the vehicles chosen to deliver and present the key molecules to the targeted cell populations are of extreme importance. In this work, a new platform for the creation of T cell activator systems based on highly tailorable nanoparticles made from the natural polymer gellan gum (GG) was developed and validated. Methods GG nanoparticles were produced by a water in oil emulsion procedure, and characterized by dynamic light scattering, high resolution scanning electronic microscopy and water uptake. Their biocompatibility with cultured cells was assessed by a metabolic activity assay. Surface functionalization was performed with anti-CD3/CD28 antibodies via EDC/NHS or NeutrAvidin/Biotin linkage. Functionalized particles were tested for their capacity to stimulate CD4+ T cells and trigger T cell cytotoxic responses. Results Nanoparticles were approximately 150 nm in size, with a stable structure and no detectable cytotoxicity. Water uptake originated a weight gain of up to 3200%. The functional antibodies did efficiently bind to the nanoparticles, as confirmed by SDS-PAGE, which then targeted the desired CD4+ populations, as confirmed by confocal microscopy. The developed system presented a more sustained T cell activation over time when compared to commercial alternatives. Concurrently, the expression of higher levels of key cytotoxic pathway molecules granzyme B/perforin was induced, suggesting a greater cytotoxic potential for future application in adoptive cancer therapy. Conclusions Our results show that GG nanoparticles were successfully used as a highly tailorable T cell activator system platform capable of T cell expansion and re-education.

Particle-Based Artificial Antigen-Presenting Cell Systems for T Cell Activation in Adoptive T Cell Therapy

“…120,121 For example, a hydrogel-based nanoscale aAPC has recently been developed using gellan gum (GG), a bacterial exopolysaccharide polymer. 122 The GG nanoparticles with a diameter of 140 nm were surface modified with T cell stimulatory signals anti-CD3 and anti-CD28 antibodies. CD4 + T cells coincubated with these aAPCs displayed improved T cell proliferation with a higher expression of proliferative IL-2 and cytotoxic factors (Figure 8e) while maintaining low levels of exhaustion.…”

“…(e) Activation profile of murine splenocytes upon stimulation with different concentrations of npGG aAPCs. In vivo assessment of CD4 + T-cell proliferation through CFSE dilution (left) and IL-2 production (right) by murine splenocytes, following a 7-day stimulation with both anti-CD3 and anti-CD28 GG particles at a 1:1 ratio . Reprinted with permission under a Creative Commons CC BY License from ref .…”

“…Hydrogel materials from natural polymers such as polysaccharides offer advantages for designing aAPCs, particularly their softness, biocompatibility, and biodegradability. , For example, a hydrogel-based nanoscale aAPC has recently been developed using gellan gum (GG), a bacterial exopolysaccharide polymer . The GG nanoparticles with a diameter of 140 nm were surface modified with T cell stimulatory signals anti-CD3 and anti-CD28 antibodies.…”

Recent Advancements in Biomaterials for Chimeric Antigen Receptor T Cell Immunotherapy

“…However, the logical relationship between these factors is unclear. This study presented a novel perspective on the utilization of hydrogels in the context of CAR-T therapy [ 26 ].…”

“…Other disadvantages incompletely include functional aberration during storage, exhaustion under in vitro activation, cytotoxicity brought by traditional transduction, and cell intolerance to TME [ 22 – 24 ]. Facing these shortcomings, appropriate development of biomaterials offer assistance in every procedure such as bio-instructive implantable scaffolds that allowed in vivo transduction and release of CAR-T to extensively shorten the manufacture time [ 25 ] and nanomaterials for normalizing the TME [ 26 ]. The more comprehensive application of biomaterials will be illustrated below.…”