Folia Parasitologica 66:013 (2019) | DOI: 10.14411/fp.2019.013

Toxoplasma gondii RPL40 is a circulating antigen with immune protection effect

Junxin Xue^1,2,3, Wei Jiang¹, Jian Li³, Wei Xiong³, Zhengan Tian³, Qiang Zhang³, Shuqing Li³, Chunfeng Liu³, Kehe Huang^2*, Quan Wang^1*

¹ Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Science, Shanghai, P. R. China;

² College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, P. R. China;

³ Shanghai Customs, Shanghai, P. R. China

Screening and identification of protective antigens are essential for the prevention of infections with Toxoplasma gondii (Nicolle et Manceaux, 1908). In our previous study, T. gondii ribosomal-ubiquitin protein L40 (TgRPL40) was identified as a circulating antigen. However, the function and protective value of TgRPL40 was unknown. In the current study, recombinant TgRPL40 was expressed in Escherichia coli BL21 and antibody was prepared. Western blotting analysis indicated that TgRPL40 was present in circulating antigens and excretory/secretary antigens (ESA). Immunofluorescence and immunoelectron microscopy analysis revealed that TgRPL40 protein is widely distributed in the tachyzoites. Immunisation with recombinant TgRPL40 prolonged the survival of mice infected with tachyzoites. Quantitative real-time polymerase chain reaction analysis showed that immunisation with recombinant TgRPL40 reduced the parasite burden in blood, liver, spleen and brain of mice infected with tachyzoites. These observations indicate that TgRPL40 is a circulating antigen and is an effector of immune protection against acute T. gondii infection.

Keywords: protein expression, subcellular localisation, protective effect

Received: December 7, 2018; Accepted: May 22, 2019; Published online: September 27, 2019  Show citation