Loss of Zbtb32 in NOD mice does not significantly alter T cell responses. [version 1; referees: 2 approved]

Background: We previously identified the transcriptional regulator Zbtb32 as a factor that can promote T cell tolerance in the Non-Obese Diabetic (NOD) mouse, a model of Type 1 diabetes. Antigen targeted to DCIR2+ dendritic cells (DCs) in vivo inhibited both diabetes and effector T cell expansion in NOD mice. Furthermore, Zbtb32 was preferentially induced in autoreactive CD4 T cells stimulated by these tolerogenic DCIR2+ DCs, and overexpression of Zbtb32 in islet-specific T cells inhibited the diabetes development by limiting T cell proliferation and cytokine production. Methods: To further understand the role of Zbtb32 in T cell tolerance induction, we have now used CRISPR to target the Zbtb32 gene for deletion directly in NOD mice and characterized the mutant mice. We hypothesized that the systemic loss of Zbtb32 in NOD mice would lead to increased T cell activation and increased diabetes pathogenesis. Results: Although NOD.Zbtb32-/- male NOD mice showed a trend towards increased diabetes incidence compared to littermate controls, the difference was not significant. Furthermore, no significant alteration in lymphocyte number or function was observed. Importantly, in vitro stimulation of lymphocytes from NOD.Zbtb32-/- mice did not produce the expected hypersensitive phenotype observed in other genetic strains, potentially due to compensation by homologous genes. Conclusions: The loss of Zbtb32 in the NOD background does not result in the expected T cell activation phenotype.