Friday, January 2, 2015

Nanoparticle Vaccines: Future Bio-Defence Drug Delivery Platforms

Growth of nanoparticles by radical-starved-feed polymerization of technical dispersions is studied with photon density wave spectroscopy Source:
In an abstract published by PubMed entitled: Vaccine Delivery using Nanoparticles, authors' Gregory, Titball and Williamson, contend: 

"Vaccination has had a major impact on the control of infectious diseases. However, there are still many infectious diseases for which the development of an effective vaccine has been elusive. In many cases the failure to devise vaccines is a consequence of the inability of vaccine candidates to evoke appropriate immune responses. This is especially true where cellular immunity is required for protective immunity and this problem is compounded by the move toward devising sub-unit vaccines. Over the past decade nanoscale size (<1000 nm) materials such as virus like particles, liposomes, ISCOMs, polymeric, and non-degradable nanospheres have received attention as potential delivery vehicles for vaccine antigens which can both stabilize vaccine antigens and act as adjuvants. Importantly, some of these nanoparticles (NPs) are able to enter antigen-presenting cells by different pathways, thereby modulating the immune response to the antigen. This may be critical for the induction of protective Th1-type immune responses to intracellular pathogens. Their properties also make them suitable for the delivery of antigens at mucosal surfaces and for intradermal administration. In this review we compare the utilities of different NP Systems for the delivery of sub-unit vaccines and evaluate the potential of these delivery systems for the development of new vaccines against a range of pathogens." See: 

Thanavala Lab concisely explains the advantages of nanoparticle vaccines: "Nanomedicine is an emerging field by which drugs, therapeutic and imaging agents and vaccines can be delivered effectively, since their bioavailability and pharmacokinetics can be improved by encapsulation with nanoparticles. A significant advantage of using biodegradable polymers are their long safety history, proven biocompatibility and ability to control the time and rate of polymer degradation and encapsulated cargo release; these qualities make them attractive for the formulation of nanoparticle based vaccine delivery systems. Current vaccines face ongoing challenges in terms of both efficacy and ease of delivery. Cancers and many chronic diseases have yet to be prevented by vaccination and several vaccines require multiple injections. Thanavala Lab states that they have begun to test the hypothesis that: vaccine antigens that are conjugated to or loaded within nanoparticles are protected from rapid degradation in vivo, allowing slow and sustained stimulation of immune responses thereby reducing the need for multiple doses; that judiciously chosen biodegradable nanoparticle formulations will allow oral vaccine delivery; and that following uptake by DCs the antigen is released intracellularly and stimulates robust innate and protective adaptive immune responses. In recent years, significant effort has been devoted to develop nanoparticle/microparticle mediated vaccine delivery systems prepared from bio-degradable and biocompatible plolymers. A wide variety of polymeric materials have been explored in order to induce systemic and local immune response after administration by various routes."

Nanoparticle delivery platforms could increase our ability to rapidly target and treat deliberate diseases for which there currently is no treatment, and in many instances, no vaccine available due to a number of both technical and cost related issues. Category A agents and those suitable for biological warfare, often have no vaccine candidates, due to lack of funding, investment, research and development. Nanoparticle platforms could reduce several inhibitors often cited as reasons for lack of R and D.  Moreover, the development of such platforms would likely offer swift treatment vs. often delayed treatment which compromises the patient. Several pharmaceutical firms are currently working with nanoparticle vaccine drug delivery platforms and recombinant NP vaccines. Moving from nanoparticle delivery platforms to NP vaccine development, Novavax for example is working on recombinant nanoparticle vaccines. 

Novavax describes their recombinant NP vaccine technology: "Unlike traditional vaccines that are based on killed viruses or live, attenuated viruses, Novavax uses recombinant technology that allows us to customize the components of our vaccine candidates in order to solve challenges presented by novel infectious diseases. For example, in the event of a pandemic influenza threat caused by a new influenza strain, our scientists will be able to utilize the genetic code of the novel pandemic influenza viruses provided by the World Health Organization and produce, in a matter of weeks, a vaccine candidate designed to generate protective immunity to specifically target that novel virus. Generally our vaccines are composed of one or more critical surface proteins of the specific virus or pathogen we are targeting. In the case of influenza, Novavax' influenza vaccines contain the important surface proteins known as hemagglutinin and neuraminidase. These proteins are designed to induce immunity in the vaccine recipient, which neutralizes the virus and creates protection against further exposure to the disease." See:

While there are many very promising pharmaceuticals working in the field of NP vaccines and delivery platforms, Novavax and Medicago are certainly the forerunners in my view, with impressive results to date in this field.

Dr.Jill Bellamy is an internationally recognized expert on biological warfare and defence. She has formerly advised NATO and for the past seventeen years has represented a number of bio-pharmaceutical and government clients working on procurement strategy between NATO MS and Washington DC. Her private government relations consultancy Warfare Technology Analytics is based in the Netherlands. Dr. Bellamy's articles have appeared in the National Review, The Wall Street Journal, The Washington Post, The Sunday Times of London, Le Temps, Le Monde and the Jerusalem Post among other publications. She is a CBRN SME with the U.S. Department of Defence, Chemical, Biological, Radiological and Nuclear Defence Information Analysis Center and CEO of Warfare Technology Analytics.

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