José Crecente-Campo

Modulating the immune system through nanotechnology

Nowadays, nanotechnology-based modulation of the immune system is presented as a cutting-edge strategy, which may lead to significant improvements in the treatment of severe diseases. In particular, efforts have been focused on the development of nanotechnology-based vaccines, which could be used for immunization or generation of tolerance. In this review, we highlight how different immune responses can be elicited by tuning nanosystems properties. In addition, we discuss specific formulation approaches designed for the development of anti-infectious and anti-autoimmune vaccines, as well as those intended to prevent the formation of antibodies against biologicals.

New scaffolds encapsulating TGF-β3/BMP-7 combinations driving strong chondrogenic differentiation

&NA; The regeneration of articular cartilage remains an unresolved question despite the current access to a variety of tissue scaffolds activated with growth factors relevant to this application. Further advances might result from combining more than one of these factors; here, we propose a scaffold composition optimized for the dual delivery of BMP‐7 and TGF‐&bgr;3, two proteins with described chondrogenic activity. First, we tested in a mesenchymal stem cell micromass culture with TGF‐&bgr;3 whether the exposure to microspheres loaded with BMP‐7 would improve cartilage formation. Histology and qRT‐PCR data confirmed that the sustained release of BMP‐7 cooperates with TGF‐&bgr;3 towards chondrogenic differentiation. Then, we optimized a scaffold prototype for tissue culture and dual encapsulation of BMP‐7 and TGF‐&bgr;3. The scaffolds were prepared from poly(lactic‐co‐glycolic acid), and BMP‐7/TGF‐&bgr;3 were loaded as nanocomplexes with heparin and Tetronic 1107. The scaffolds showed the sustained release of both proteins over four weeks, with minimal burst effect. We finally cultured human mesenchymal stem cells on these scaffolds, in the absence of exogenous chondrogenic factor supplementation. The cells cultured on the scaffolds loaded with BMP‐7 and TGF‐&bgr;3 showed clear signs of cartilage formation macroscopically and histologically. RT‐PCR studies confirmed a clear upregulation of cartilage markers SOX9 and Aggrecan. In summary, scaffolds encapsulating BMP‐7 and TGF‐&bgr;3 can efficiently deliver a cooperative growth factor combination that drives efficient cartilage formation in human mesenchymal stem cell cultures. These results open attractive perspectives towards in vivo translation of this technology in cartilage regeneration experiments. Graphical abstract Figure. No caption available. HighlightsThe sustained delivery of BMP‐7 enhances the chondrogenic activity of TGF‐&bgr;3.BMP‐7 and TGF‐&bgr;3 can be entrapped in polymers matrices as PEG‐heparin complexes.Scaffolds delivering TGF‐&bgr;3 and BMP‐7 drive the chondrogenesis of cell progenitors.

Mauritian cynomolgus macaques with M3M4 MHC genotype control SIVmac251 infection

Understanding natural HIV control may lead to new preventative or therapeutic strategies. Several protective major histocompatibility complex (MHC) genotypes were found in humans and rhesus macaques. Here, we report a simian immunodeficiency virus (SIV) controller MHC genotype in Mauritian cynomolgus macaques (MCMs).

Bilayer polymeric nanocapsules: A formulation approach for a thermostable and adjuvanted E. coli antigen vaccine

ABSTRACT One of the strategies used to improve the immunogenicity of purified protein antigens has relied on their association with synthetic nanocarriers, which, in general, have functioned as simple antigen containers. Here, we present a more advanced strategy based on the design of an antigen nanocarrier at the molecular level. The nanocarrier is composed of a vitamin E oily core, surrounded by two layers: a first layer of chitosan and a second of dextran sulphate. The selected antigen, IutA protein from Escherichia coli, was harboured between the two polymeric layers. The final bilayer nanocapsules had a nanometric size (≈ 200 nm), a negative zeta potential (< ‐40 mV) and a good antigen association efficiency (≈ 70%). The bilayer architecture led to an improvement on the formulation stability and the controlled release of the associated antigen. Remarkably, after being administered to mice, bilayer nanocapsules elicited higher IgG levels than those obtained with antigen precipitated with Alum. Moreover, freeze‐dried nanocapsules were stable at room temperature for, at least, 3 months. These promising data, in addition to their contribution to the development of an uropathogenic E. coli vaccine, has allowed us to validate these novel bilayer nanocapsules as adequate platforms for the delivery of protein antigens. Graphical abstract Figure. No caption available. HighlightsBilayer nanocapsules protect and control the delivery of their associated antigens.Freeze‐dried nanocapsules are stable for at least 3 months at room temperature.Antigen‐loaded bilayer nanocapsules elicit higher IgG levels in mice than Alum.

Mucosal antibody responses to vaccines targeting SIV protease cleavage sites or full-length Gag and Env proteins in Mauritian cynomolgus macaques

HIV mutates rapidly and infects CD4+ T cells, especially when they are activated. A vaccine targeting conserved, essential viral elements while limiting CD4+ T cell activation could be effective. Learning from natural immunity observed in a group of highly HIV-1 exposed seronegative Kenyan female sex workers, we are testing a novel candidate HIV vaccine targeting the 12 viral protease cleavage sites (PCSs) (the PCS vaccine), in comparison with a vaccine targeting full-length Gag and Env (the Gag/Env vaccine) in a Mauritian cynomolgus macaque/SIV model. In this study we evaluated these vaccines for induction of mucosal antibodies to SIV immunogens at the female genital tract. Bio-Plex and Western blot analyses of cervicovaginal lavage samples showed that both the PCS and Gag/Env vaccines can elicit mucosal IgG antibody responses to SIV immunogens. Significantly higher increase of anti-PCS antibodies was induced by the PCS vaccine than by the Gag/Env vaccine (p<0.0001). The effect of the mucosal antibody responses in protection from repeated low dose pathogenic SIVmac251 challenges is being evaluated.

Engineering, on-demand manufacturing, and scaling-up of polymeric nanocapsules

Abstract Polymeric nanocapsules are versatile delivery systems with the capacity to load lipophilic drugs in their oily nucleus and hydrophilic drugs in their polymeric shell. The objective of this work was to expand the technological possibilities to prepare customized nanocapsules. First, we adapted the solvent displacement technique to modulate the particle size of the resulting nanocapsules in the 50–500 nm range. We also produced nanosystems with a shell made of one or multiple polymer layers i.e. chitosan, dextran sulphate, hyaluronate, chondroitin sulphate, and alginate. In addition, we identified the conditions to translate the process into a miniaturized high‐throughput tailor‐made fabrication that enables massive screening of formulations. Finally, the production of the nanocapsules was scaled‐up both in a batch production, and also using microfluidics. The versatility of the properties of these nanocapsules and their fabrication technologies is expected to propel their advance from bench to clinic.