Development of nano-carriers for Leishmania vaccine delivery

ABSTRACT

Introduction: Leishmaniasis is a neglected tropical infection caused by several species of intracellular protozoan parasites of the genus Leishmania. It is strongly believed that the development of vaccines is the most appropriate approach to control leishmaniasis. However, there is no vaccine available yet and the lack of an appropriate adjuvant delivery system is the main reason.

Areas covered: Adjuvants are the utmost important part of a vaccine, to induce the immune response in the right direction. Limitations and drawbacks of conventional adjuvants have been necessitated the development of novel particulate delivery systems as adjuvants to obtain desirable protection against infectious diseases such as leishmaniasis. This review focused on particulate adjuvants especially nanoparticles that are in use to develop vaccines against leishmaniasis. The list of adjuvants includes generally lipids-, polymers-, or mineral-based delivery systems that target antigens specifically to the site of action within the host’s body and enhance immune responses.

Expert opinion: Over the past few years, there has been an increasing interest in developing particulate adjuvants as alternatives to immunostimulatory types. The composition of nano-carriers and particularly the physicochemical properties of nanoparticles have great potential to overcome challenges posed to leishmaniasis vaccine developments.

KEYWORDS:

• Adjuvants
• antigen delivery
• leishmaniasis vaccine
• nano-carrier

Article highlights

• Background information of leishmaniasis, its vaccine types, and an essential need to development of new vaccines or adjuvants are provided.

• General concepts of adjuvants to improve immune response and some advantages to vaccine development are presented. Immunostimulatory adjuvants and particulate adjuvants are two main categories of adjuvants in the Leishmania vaccines.

• This article focused on the potential application of nanoparticulate delivery systems such as liposome, noisome, emulsion, and polymeric particles that were investigated for leishmaniasis vaccines over past years.

• Particulate delivery systems are able to encapsulate antigens, deliver efficiently them to APCs, especially dendritic cells, and enhance immune responses.

• The combination of immunostimulatory adjuvants with particulate delivery systems or surface modification of particulates with targeting ligands may lead to produce a strong and specific immune response.

This box summarizes the key points contained in the article.

Declaration of interest

The authors have no relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript. This includes employment, consultancies, honoraria, stock ownership or options, expert testimony, grants or patents received or pending, or royalties.

Reviewer disclosures

Peer reviewers on this manuscript have no relevant financial or other relationships to disclose.

Additional information

Funding

This paper was not funded.