Moving towards improved vaccines for Toxoplasma gondii

ABSTRACT

Introduction: Toxoplasma gondii is an intracellular parasitic protozoan that infects almost all warm-blooded animals and humans, resulting in threats to public health and economic losses. Despite continuous research efforts, there are still very few effective strategies against toxoplasmosis. In the past few years, numerous vaccination experiments have been performed to control T. gondii infection.

Areas covered: In this review, the authors summarize the development of T. gondii vaccines with proper adjuvants, ranging from live or live-attenuated vaccines to protein vaccines, DNA vaccines, epitope vaccines and novel vaccines. They also highlight the challenges involved in the development of T. gondii vaccines, including specific impediments and shortcomings.

Expert opinion: Moving towards the development of effective vaccines against T. gondii is not only a tedious mission but also a difficult challenge. Future studies should consider new approaches and strategies for vaccine development, particularly novel vaccines and genetic adjuvants, as well as optimizing immunization protocols and evaluation criteria.

KEYWORDS:

• Toxoplasma gondii
• vaccine
• novel vaccine
• immunization
• adjuvant

Article highlights

• T. gondii is an obligate intracellular Apicomplexan protozoan of cosmopolitan distribution and is of major medical and veterinary importance.

• New vaccine candidates for T. gondii have been investigated in animal models regarding their potential to trigger cellular and humoral immune responses and their protection against challenge.

• Novel vaccines, particularly exosomes, carbohydrates and RNA from T. gondii, have been evaluated, but the efficacies of these vaccines still must be strengthened.

• New adjuvants best enhance the immunogenicity of weaker antigens, determine the type of immune response generated, and improve vaccine efficacy.

• Further studies should address the pathogenic, immune and host cell invasion mechanisms associated with T. gondii as well as vaccine action against toxoplasmosis.

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

Additional information

Funding

The authors are supported by the National Natural Science Foundation of China via H Zhou in the form of a grant (81471974).