Dynamic Expressions of TIGIT on Splenic T Cells and TIGIT-Mediated Splenic T Cell Dysfunction of Mice With Chronic Toxoplasma gondii Infection

Abstract

As an immunosuppressive receptor, T-cell immunoglobulin and immunoreceptor tyrosine-based inhibitory motif domain (TIGIT) play a critical part in cellular immune regulation mediated by pathogen infection. Whereas, TIGIT expression on splenic T cells in hosts infected with Toxoplasma gondii cysts has not been studied. In this study, we detected TIGIT expression and the changes of immune function in the spleen by flow cytometry and real-time PCR (RT-PCR). We found that TIGIT expression on splenic T cells increased significantly post infection. At the same time, splenic TIGIT+TCM cells were activated and transformed into TIGIT+TEM cells during the infection, and the cytotoxicity of TIGIT+ T cells was reduced in the later stage of infection. This study shows that chronic T. gondii infection can upregulate TIGIT expression on the surface of T cells and affect immune cell function.

A pre-existing Toxoplasma gondii infection exacerbates the pathophysiological response and extent of brain damage after traumatic brain injury in mice

“…injection and a systemic immune response was evident based on the spleen weight findings. Of note, chronic T. gondii infection has been found to cause lipofuscinosis, collagenopathy, splenic T-cell dysfunction and spleen and white pulp atrophy [ 56 , 81 ]. At the acute and sub-acute recovery times, male and female T. gondii mice had increased expression of genes reflective of macrophages and lymphocytes in the brain, suggesting infiltration of peripheral immune cells that coincided with increased spleen weights.…”

“…Infection status was verified via serologic testing with a colorimetric Mouse Toxoplasmosis Antibody (IgG) ELISA Kit (NBP2-60169, Novus Biologicals, Centennial, CO, USA) using serum samples collected from T. gondii and vehicle-injected mice at the time of euthanasia. As increased spleen weight is characteristic in chronic T. gondii infection [ 56 ], fresh spleen weights were also used as an indicator of infection (Fig. 2 C–J).…”