Assessment of silica nanoparticles internalization by alpha-type-1 polarized dendritic cells (αDC1) — ASN Events
  1. Schedule
  2. Poster Session 2
  3. Assessment of silica nanoparticles internalization by alpha-type-1 polarized dendritic cells (αDC1)

Assessment of silica nanoparticles internalization by alpha-type-1 polarized dendritic cells (αDC1) (#202)

Silvia de Jesus Mota 1 , Bruna Tiaky Tiyo 1 , Lais Teodoro da Silva 1 , Marina Mazzilli Ortega 1 , Guilherme Castellani 1 , Vinicius Nunes Cordeiro Leal 1 , Jonnatan Julival dos Santos 1 , Robbie B Mailliard 2 , Alberto José da Silva Duarte 3 , Telma Miyuki Oshiro Sumida 3
  1. University of Sao Paulo, Sao Paulo, SAO PAULO, Brazil
  2. University of Pittsburgh, Pittsburgh, United States of America
  3. Clinicals Hospital of University of Sao Paulo, Sao Paulo, Brazil

Background: Nanoparticle-based antigen delivery systems have emerged as promising tools to enhance antigen uptake and presentation by dendritic cells. This study aimed to analyse the ability of alpha-type-1 polarized dendritic cells (αDC1) to internalize silica nanoparticles (SiNP) conjugated to an HIV antigen. 

Methods: Peripheral blood mononuclear cells (PBMCs) were obtained from six healthy donors, and CD14+ monocytes were purified by magnetic bead-based positive selection. Monocytes were cultured in the presence of granulocyte-macrophage colony-stimulating factor (GM-CSF) and interleukin-4 (IL-4) to promote differentiation into immature monocyte-derived dendritic cells (iMoDCs). Following differentiation, cell maturation was induced using a cytokine cocktail composed of interferon-α (IFN-α), interferon-γ (IFN-γ), interleukin-1β (IL-1β), tumor necrosis factor-α (TNF-α), and Poly I:C. Immature and mature DCs were incubated with SiNP conjugated to the HIV Gag27 peptide for 2, 4, or 6 hours. Cell viability and nanoparticle uptake were assessed by flow cytometry, while intracellular localization of SiNP was evaluated using fluorescence microscopy, with confocal imaging. 

Results: High cell viability was maintained across all experimental conditions, indicating that SiNP exposure did not induce significant cytotoxicity. Both immature and αDC1 exhibited time-dependent internalization of SiNP, with a significant increase in the frequency of CD11c+SiNP+ cells after 6 hours of incubation compared to non-exposed controls (p < 0.01). In parallel, median fluorescence intensity (MFI) analyses revealed an increase in intracellular nanoparticle content over time, with the highest levels observed at 6 hours.

Conclusions: A 6-hour incubation period proved to be the most efficient condition for the internalization of silica nanoparticles conjugated to the HIV Gag27 peptide by αDC1, without compromising cell viability. The combined use of fluorescence and confocal microscopy confirmed effective nanoparticle uptake, reinforcing the potential of silica nanoparticles as a delivery platform to enhance  antigen presentation strategies in HIV immunotherapy.