Vaccines against Toxoplasma gondii: new developments and perspectives

Abstract

Toxoplasmosis caused by the protozoan Toxoplasma gondii is a major public health problem, infecting one-third of the world human beings, and leads to abortion in domestic animals. A vaccine strategy would be an ideal tool for improving disease control. Many efforts have been made to develop vaccines against T. gondii to reduce oocyst shedding in cats and tissue cyst formation in mammals over the last 20 years, but only a live-attenuated vaccine based on the S48 strain has been licensed for veterinary use. Here, the authors review the recent development of T. gondii vaccines in cats, food-producing animals and mice, and present its future perspectives. However, a single or only a few antigen candidates revealed by various experimental studies are limited by only eliciting partial protective immunity against T. gondii. Future studies of T. gondii vaccines should include as many CTL epitopes as the live attenuated vaccines.

Keywords::

• cat
• food animal
• mice
• Toxoplasma gondii
• toxoplasmosis
• vaccines

Financial & competing interests disclosure

Project support was provided by the National Natural Science Foundation of China (grant numbers. 31230073 and 31172316), the International Science and Technology Cooperation Project of Gansu Province (grant number 1204WCGA023) and the Science Fund for Creative Research Groups of Gansu Province (grant number 1210RJIA006). The authors have no other 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 apart from those disclosed.

No writing assistance was utilized in the production of this manuscript.

Key issues

• • Toxoplasmosis, caused by the protozoan Toxoplasma gondii, is a major public health problem, infecting at least one-third of the world population and leads to abortion and mortality in domestic animals.

• • A vaccine strategy would be ideal for improving toxoplasmosis control.

• • Many efforts have been made on the development of vaccines against T. gondii to reduce oocyst shedding in cats and tissue cyst formation in mammals in the last 20 years.

• • Considerable progress has been made in the studies of T. gondii vaccines in cats, food-producing animals as well as in the mouse models since 2009.

• • Human MHC class I restricted peptide epitopes from specific T. gondii antigens may provide a promising protective immunity in humans.

• • ROP18 was shown to be an effective vaccine candidate, and interleukins were proven as valuable adjuvants.

• • Further studies should include more CTL recognized antigens and the protective evaluation should be compared with the natural infection and live attenuated vaccines.