After Experimental <i>Trypanosoma cruzi</i> Infection, Dying Hepatic CD3<sup>+</sup>TCRαβ<sup>+</sup>B220<sup>+</sup> T Lymphocytes Are Rescued from Death by Peripheral T Cells and Become Activated

oleh: Natalia Vacani-Martins, Marcelo Meuser-Batista, Otacilio C. Moreira, Cynthia Machado Cascabulho, Daniela Gois Beghini, Samuel Iwao Horita, Marcos Meuser Batista, Fernando Cleber Freitas, Juliana Rodrigues Guimarães, Andrea Henriques-Pons

Format: Article
Diterbitkan: MDPI AG 2020-08-01

Deskripsi

The unusual phenotype of CD3<sup>+</sup> T lymphocyte expressing B220, a marker originally attributed to B lymphocytes, was first observed in the liver of Fas/Fas-L-deficient mice as a marker of apoptotic T lymphocytes. However, other CD3<sup>+</sup>B220<sup>+</sup> T lymphocyte populations were later described in the periphery as functional cytotoxic or regulatory cells, for example. Then, in this work, we studied whether hepatic CD3<sup>+</sup>B220<sup>+</sup> T lymphocytes could play a role in experimental <i>Trypanosoma cruzi</i> infection. In control and infected mice, we observed two subpopulations that could be discerned based on CD117 expression, which were conventional apoptotic CD3<sup>+</sup>B220<sup>+</sup>(CD117<sup>−</sup>) and thymus-independent CD3<sup>+</sup>B220<sup>+</sup>CD117<sup>+</sup> T lymphocytes. Regardless of CD117 expression, most B220<sup>+</sup> T lymphocytes were 7AAD<sup>+</sup>, confirming this molecule as a marker of dying T cells. However, after infection, we found that around 15% of the CD3<sup>+</sup>B220<sup>+</sup>CD117<sup>+</sup> hepatic population became B220 and 7AAD negative, turned into CD90.2<sup>+</sup>, and upregulated the expression of CD44, CD49d, and CD11a, a phenotype consistent with activated T lymphocytes. Moreover, we observed that the hepatic CD3<sup>+</sup>B220<sup>+</sup>CD117<sup>+</sup> population was rescued from death by previously activated peripheral T lymphocytes. Our results extend the comprehension of the hepatic CD3<sup>+</sup>B220<sup>+</sup> T lymphocyte subpopulations and illustrate the complex interactions that occur in the liver.