Toxoplasma gondii Suppresses Th2-Induced by Trichinella spiralis Infection and Downregulates Serine Protease Genes Expression: A Critical Role in Vaccine Development.

Background: Toxoplasma gondii coinfection can modify host immune responses and the severity and spread of other parasites. We investigated how T. gondii and Trichinella spiralis infections counter-regulate each other's immune responses. Methods: The parasite burden, the expression of T. gondii rhoptry kinase ROP18 and T. spiralis putative serine protease (TsSP), the IgG1 and IgG2a responses, besides histopathological and immunohistochemical staining with iNOS and arginase were used to evaluate the dynamics of coinfection. Results: Through their effects on host immune responsiveness, coinfection with T. gondii modified the virulence of T. spiralis infection. Coinfected animals with high and low doses of T. gondii demonstrated significant reductions in the T. spiralis burden of 75.2% and 68.2%, respectively. TsSP expression was downregulated in both groups by 96.2% and 86.7%, whereasROP18 expression was downregulated by only 6% and10.6%, respectively. In coinfected mice, elevated levels of T. gondii-specific IgG2a antibodies were detected. Th1 induced by T. gondii inhibits the Th2 response to T. spiralis in coinfected animals with high iNOS expression andlow-arginine1 expression. Conclusion: T. gondii infection induces a shift toward a Th1-type immune response while suppressing a helminth-specific Th2 immune response, paving the way for developing novel vaccines and more efficient control strategies.

The relationship between toxoplasmosis and different types of human tumors.

INTRODUCTION: Toxoplasma gondii is an intracellular protozoan that may disrupt the traditional cell barriers against cancer, allowing the accumulation of oncogenic mutations over time. Our research aimed to explore the relationship between T. gondii infection and tumor development. METHODOLOGY: The anti-T. gondii IgG and IgM antibodies were tested for156 patients with tumors (51 with breast cancer, 20 with hepatoma, 20 with larynx carcinoma, 20 with squamous cell carcinoma of bone, 16 with lymphoma, 13 with brain tumor, 4 with bladder cancer and 12 with benign uterine tumor) and 90 healthy controls by using electrochemiluminescence immunoassay. Tissue specimens were collected from T. gondii seropositive cases for histological and immunohistochemistry (IHC) examinations. RESULTS: The seroprevalence of human toxoplasmosis in the Sharkia Governorate, Egypt is significantly correlated with various types of tumors: breast cancer in 49 subjects (96.1%), and squamous cell carcinoma of bone in 16 subjects (80%). It was also present in nine cases of brain tumors. Anti-Toxoplasma IgG was detected in seven cases of liver tumors and one-quarter of bladder cancer. The anti- Toxoplasma IgM was present in three patients with benign uterine tumors, one patient with a bone tumor and two patients with breast cancer. Toxoplasma cysts were detected in immunostained brain sections. CONCLUSION: The correlation between T. gondii infection and tumors was established by this study indicating a significant emerging role of human toxoplasmosis in the etiology or existence of particular types of tumors.