Functionalized carbon nanotubes as immunomodulator systems

Abstract

In view of the broad potential biomedical applications of carbon nanotubes (CNTs) different studies were performed to assess their effect on the immune system. However, the work performed to date was able to give a restricted view looking only at some activation markers and cytokine expression. The immune system is rarely limited to few molecule interactions being instead always a balance of switching several genes on and off. Whole genome expression (microarray) is a technology able to give the full picture on genome expression. Here we describe a microarray genome-wide study on Jurkat cells, a T lymphocyte cell line, and THP1, a monocytic cell line, representative of both types of immune response, the adaptive and innate, respectively. Since any structure or molecule modification may lead to very different immune reactions, we treated the two cell lines with four types of functionalized multi-walled CNTs that differ in terms of functionalization and diameter. After having assessed the internalization and the lack of toxicity of CNTs in both cell types, we used the Affymetrix technology to analyze the expression of about 32,000 transcripts. Three of the tested nanotubes (i.e., ox-MWCNT-1, ox-MWCNT-NH3(+)-1, and ox-MWCNT-NH3(+)-2) activated immune-related pathways in monocytes but not in T cells. In view of these charateristics they were named as monocyte activating CNTs (MA-CNTs). Molecular pathways upregulated by MA-CNTs included IL6, CD40, dendritic cell maturation, tumor necrosis factor-(TNF)-α/TNFR1-2, NFKB signaling and T helper 1 chemokine pathways (CXCR3 and CCR5 ligand pathways). These pathways are commonly activated during acute inflammatory processes as those associated with immune-mediated tumor rejection and pathogen clearance. One of them (i.e., ox-MWCNT-2) downregulated genes associated with ribosomal proteins in both monocytes and T cells. We validated our findings at gene expression level by performing real-time PCR assessing the most highly modulated genes in monocytes. To confirm the results at protein level, the secretion of IL1β, TNFα, IL6 and IL10 by THP1 and primary monocytes was assessed by ELISA, corroborating gene-expression data. Our results provide new insights into the whole gene expression modulation by different CNTs on immune cells. Considering the well known drug carrier ability of CNTs, our findings demonstrate that MA-CNTs here behave as cell specific immunostimulatory systems, giving very interesting future perspectives for their application also as immunotherapeutic agents and/or vaccine adjuvants.

Systemic and immunotoxicity of pristine and PEGylated multi-walled carbon nanotubes in an intravenous 28 days repeated dose toxicity study

“…7 Due to their importance in the immune system, studies have reported the effects of CNTs on the functionality and viability of immune cells such as T and B lymphocytes, macrophages, dendritic cells, natural killer (NK) cells in vitro, focusing on toxicity, oxidative stress, cytokine induction, and inhibition of key functions such as phagocytosis. [8][9][10][11][12][13] Pescatori et al 8 showed that four types of functionalized multi-walled carbon nanotubes (f-MWCNTs) showed no cytotoxicity on Jurkat T and monocyte THP-1 cells, but three types of those f-MWCNTs activate the expression of pro-inflammatory genes in THP-1, whereas no significant activation was observed in T cells. Pristine multi-walled carbon nanotubes (p-MWCNTs) were not able to cause secretion of cytokine in peripheral blood mononuclear cells (PBMCs), but could increase TLR agonist-induced cytokine secretion and PHAinduced T-cell cytokine release by PBMC.…”

The winding road for carbon nanotubes in nanomedicine

“…Interestingly, only the former led to homogeneous dispersions with no visible aggregates and a lack of proinflammatory response by macrophages, confirming the importance of having a homogeneous distribution of functionalization sites along the CNT surface [45]. Lack of cytotoxicity for NH 3 + -TEG-CNTs, previously shortened to about 400 nm via oxidation, has been confirmed also in separate studies [46,47].…”

“…topography, chemical functionalization and diameter) can also be exploited to selectively activate either innate or adaptive immune response, depending on the intended application (e.g. CNT vaccine design) [36,46,85].…”

Development of Carbon Nanotubes-Based Immunogens

“…Some authors say that this new identity could represent a novel type of molecular pattern to be recognized by the immune system and thus elicit immune responses. Once added o a vaccine formulation, these NAMPs (Nanoparticle-associated molecular patterns) could work as adjuvants and help initiating the innate response [21]. In fact, a lot of attention has been drawn to modeling nanoparticles, in particular CNTs, in order to create the perfect delivery system that could also be capable of acting as an adjuvant.…”