Investigation of infectivity of neonates and adults from different rat strains to Toxoplasma gondii Prugniaud shows both variation which correlates with iNOS and Arginase-1 activity and increased susceptibility of neonates to infection

Abstract

Mouse models differ considerably from humans with regard to clinical symptoms of toxoplasmosis caused by Toxoplasma gondii and, by comparison, the rat model is more representative of this disease in humans. In the present study, we found that different strains of adult and newborn rats (Lewis, Wistar, Sprague Dawley, Brown Norway and Fischer 344) exhibited remarkable variation in the number of brain cysts following inoculation with the T.gondii Prugniaud strain. In adult rats, large numbers of cysts (1231 ± 165.6) were observed in Fischer 344, but none in the other four. This situation was different in newborn rats aged from 5 to 20 days old. All Fischer 344 and Brown Norway newborns were cyst-positive while cyst-positive infection in Sprague Dawley neonates ranged from 54.5% to 60% depending on their age at infection. In Wistar and Lewis rat neonates, however, cyst-positivity rates of 0-42.9% and 0-25% were found respectively. To investigate whether rat strain differences in infectivity could be related to inherent strain and genetic differences in the host immune response, we correlated our data with previously reported strain differences in iNOS/Arginase ratio in adult rats and found them to be linked. These results show that interactions between host genetic background and age of rat influence T.gondii infection.

Guanylate-binding protein 1 (GBP1) contributes to the immunity of human mesenchymal stromal cells against Toxoplasma gondii

“…The iNOS-mediated production of NO is a well-known molecular effector against pathogens in the innate immune responses of various animals, including mMSCs (9) and skeletal muscle cells (27), and also in vivo (15,30,31). However, a previous study reported that iNOS protein expression was not detectable in human MSCs (9).…”

Genetic analyses of Chinese isolates of Toxoplasma gondii reveal a new genotype with high virulence to murine hosts

“…3A). Therefore, for analysis of cyst-forming ability, the rat model system, based on the innate resistance of rats to T. gondii (Gao et al, 2015;Li et al, 2012), is much more useful. In comparison to the archetype II PRU strain, which itself is capable of cyst formation in certain rat strains, the Chinese strains of TgCtsd1 and TgCtxz3 produced over 200 times more cysts.…”

An experimental genetically attenuated live vaccine to prevent transmission of Toxoplasma gondii by cats

“…The use of CBA/Rj mice and Fischer 344/IcoCrl rats as hosts for T . gondii has been described previously 59,60 . At 48 or 49 days post-injection, blood samples from five randomly-chosen mice and rats were taken and tested for antibody production by ELISA (see below); all were antibody-positive.…”