Batf3, also known as basic leucine zipper transcription factor ATF-like 3, is a transcription factor. It is essential in the development of mucosal conventional DCs type 1 (cDC1) [2]. It is involved in multiple biological processes related to the immune system, including T-cell-mediated immunity and maintaining intestinal epithelial homeostasis. Genetic models, such as gene knockout mouse models, are valuable tools for studying its functions.

In Batf3 -/- mice, the development of CD8α+ dendritic cells was ablated. These mice were defective in cross-presentation, lacked virus-specific CD8+ T cell responses to West Nile virus, and had impaired rejection of highly immunogenic syngeneic tumors, suggesting an important role for CD8α+ dendritic cells and cross-presentation in responses to viruses and in tumor rejection [1]. Batf3 -/- mice also developed metabolic syndrome, had altered localization of tight junction proteins in intestinal epithelial cells leading to increased intestinal permeability, and displayed microbial dysbiosis [2]. Additionally, T cells lacking Batf3 showed normal expansion and differentiation but an aggravated contraction and a diminished memory response, while overexpression of BATF3 in CD8+ T cells promoted their survival and transition to memory [3].

In conclusion, Batf3 plays crucial roles in the immune system, including in T-cell-mediated immunity, virus responses, tumor rejection, and maintaining intestinal epithelial homeostasis. The Batf3 knockout mouse models have significantly contributed to understanding its functions in these disease-related areas such as viral infections, tumor immunity, and metabolic syndrome.