Previous Infection with Plasmodium berghei Confers Resistance to Toxoplasma gondii Infection in Mice

Abstract

Both Plasmodium spp. and Toxoplasma gondii are important apicomplexan parasites, which infect humans worldwide. Genetic analyses have revealed that 33% of amino acid sequences of inner membrane complex from the malaria parasite Plasmodium berghei is similar to that of Toxoplasma gondii. Inner membrane complex is known to be involved in cell invasion and replication. In this study, we investigated the resistance against T. gondii (ME49) infection induced by previously infected P. berghei (ANKA) in mice. Levels of T. gondii-specific IgG, IgG1, IgG2a, and IgG2b antibody responses, CD4 + and CD8 + T cell populations were found higher in the mice infected with P. berghei (ANKA) and challenged with T. gondii (ME49) compared to that in control mice infected with T. gondii alone (ME49). P. berghei (ANKA) + T. gondii (ME49) group showed significantly reduced the number and size of T. gondii (ME49) cysts in the brains of mice, resulting in lower body weight loss compared to ME49 control group. These results indicate that previous exposure to P. berghei (ANKA) induce resistance to subsequent T. gondii (ME49) infection.

Retrospective study of toxoplasmosis prevalence in pregnant women in Benin and its relation with malaria

“…Another explanation could be that the persistent installation of T. gondii in its host involves a dynamic regulation of combined cellular and molecular immunoregulatory networks [52][53][54][55], which can impact the newly infecting Plasmodium parasite using similar pathways. This could result in less production of anti-PfAMA1 IgG to effectively fight plasmodial parasites.…”

Protective mucosal and systemic immunity induced by virus-like particles expressing Toxoplasma gondii cyst wall protein

“…gondii ME49 strain, which includes VLPs co-expressing the inner membrane complex (IMC), rhoptry protein 18 (ROP18), and microneme protein 8 (MIC8) [ 25 , 32 , 45 ]. Other VLPs co-displaying the ROP4 and ROP13 antigens [ 31 , 46 ] or the MIC8 and ROP18 antigens have been generated and their efficacies were evaluated in mice [ 20 ]. Surprisingly, the CST1 VLPs generated in this study demonstrated the strongest brain cyst inhibition, surpassing those reported in our previous works.…”

“…Four weeks after the boost immunization, mice were orally challenge-infected with 450 T . gondii ME49 cysts as previously described [ 31 ]. Briefly, the brain tissues of T .…”

“…Three weeks after each immunization, blood samples of individual mice were collected by retro-orbital plexus puncture and centrifuged at 6,000 rpm, 10 min, 4 °C for serum acquisition. At 40 days post-infection (dpi), mice were sacrificed and intestines were acquired as previously described [ 31 ]. Duodenums of mice were longitudinally cut and immersed in 500 μl of PBS.…”

“…At 40 dpi, mice were sacrificed and spleens were collected. Spleens were homogenized to prepare single cell suspensions of splenocytes, which were counted under the microscope using a hemocytometer as previously described [ 31 ]. Tg ME49 Ag were used to coat the 96-well cell culture plates at a concentration of 4 μg/ml in 0.05 M, pH 9.6 carbonate bicarbonate buffer overnight at 4 °C.…”