{"database":"biostudies-literature","file_versions":[],"scores":null,"additional":{"submitter":["Knudson CJ"],"funding":["NIA NIH HHS","NIAID NIH HHS","HHS | NIH | National Institute on Aging (NIA)","HHS | NIH | National Institute of Allergy and Infectious Diseases","NCI NIH HHS","HHS | NIH | National Institute on Aging","HHS | NIH | National Institute of Allergy and Infectious Diseases (NIAID)"],"pagination":["e0056621"],"full_dataset_link":["https://www.ebi.ac.uk/biostudies/studies/S-EPMC8428409"],"repository":["biostudies-literature"],"omics_type":["Unknown"],"volume":["95(19)"],"pubmed_abstract":["Cytotoxic CD4 T lymphocytes (CD4-CTL) are important in antiviral immunity. For example, we have previously shown that in mice, CD4-CTL are important to control ectromelia virus (ECTV) infection. How viral infections induce CD4-CTL responses remains incompletely understood. We demonstrate here that not only ECTV but also vaccinia virus and lymphocytic choriomeningitis virus induce CD4-CTL, though the response to ECTV is stronger. Using ECTV, we also demonstrate that in contrast to CD8-CTL, CD4-CTL differentiation requires constant virus replication and ceases once the virus is controlled. We also show that major histocompatibility complex class II molecules on CD11c<sup>+</sup> cells are required for CD4-CTL differentiation and for mousepox resistance. Transcriptional analysis indicated that antiviral CD4-CTL and noncytolytic T helper 1 (Th1) CD4 T cells have similar transcriptional profiles, suggesting that CD4-CTL are terminally differentiated classical Th1 cells. Interestingly, CD4-CTL and classical Th1 cells expressed similar mRNA levels of the transcription factors ThPOK and GATA-3, necessary for CD4 T cell linage commitment, and Runx3, required for CD8 T cell development and effector function. However, at the protein level, CD4-CTL had higher levels of the three transcription factors, suggesting that further posttranscriptional regulation is required for CD4-CTL differentiation. Finally, CRISPR/Cas9-mediated deletion of <i>Runx3</i> in CD4 T cells inhibited CD4-CTL but not classical Th1 cell differentiation in response to ECTV infection. These results further our understanding of the mechanisms of CD4-CTL differentiation during viral infection and the role of posttranscriptionally regulated Runx3 in this process. <b>IMPORTANCE</b> While it is well established that cytotoxic CD4 T cells (CD4-CTLs) directly contribute to viral clearance, it remains unclear how CD4-CTL are induced. We now show that CD4-CTLs require sustained antigen presentation and are induced by CD11c-expressing antigen-presenting cells. Moreover, we show that CD4-CTLs are derived from the terminal differentiation of classical T helper 1 (Th1) subset of CD4 cells. Compared to Th1 cells, CD4-CTLs upregulate protein levels of the transcription factors ThPOK, Runx3, and GATA-3 posttranscriptionally. Deletion of Runx3 in differentiated CD4 T cells prevents induction of CD4-CTLs but not classical Th1 cells. These results advance our knowledge of how CD4-CTLs are induced during viral infection."],"journal":["Journal of virology"],"pubmed_title":["Mechanisms of Antiviral Cytotoxic CD4 T Cell Differentiation."],"pmcid":["PMC8428409"],"funding_grant_id":["P30 CA056036","R01 AI110457","R01AI110457","R01 AI065544","AG048602","R01 AG048602","T32 AI134646"],"pubmed_authors":["Melo-Silva CR","Erkes DA","Tang L","Alves-Peixoto P","Ferez M","Knudson CJ","Sigal LJ","Snyder CM"],"additional_accession":[]},"is_claimable":false,"name":"Mechanisms of Antiviral Cytotoxic CD4 T Cell Differentiation.","description":"Cytotoxic CD4 T lymphocytes (CD4-CTL) are important in antiviral immunity. For example, we have previously shown that in mice, CD4-CTL are important to control ectromelia virus (ECTV) infection. How viral infections induce CD4-CTL responses remains incompletely understood. We demonstrate here that not only ECTV but also vaccinia virus and lymphocytic choriomeningitis virus induce CD4-CTL, though the response to ECTV is stronger. Using ECTV, we also demonstrate that in contrast to CD8-CTL, CD4-CTL differentiation requires constant virus replication and ceases once the virus is controlled. We also show that major histocompatibility complex class II molecules on CD11c<sup>+</sup> cells are required for CD4-CTL differentiation and for mousepox resistance. Transcriptional analysis indicated that antiviral CD4-CTL and noncytolytic T helper 1 (Th1) CD4 T cells have similar transcriptional profiles, suggesting that CD4-CTL are terminally differentiated classical Th1 cells. Interestingly, CD4-CTL and classical Th1 cells expressed similar mRNA levels of the transcription factors ThPOK and GATA-3, necessary for CD4 T cell linage commitment, and Runx3, required for CD8 T cell development and effector function. However, at the protein level, CD4-CTL had higher levels of the three transcription factors, suggesting that further posttranscriptional regulation is required for CD4-CTL differentiation. Finally, CRISPR/Cas9-mediated deletion of <i>Runx3</i> in CD4 T cells inhibited CD4-CTL but not classical Th1 cell differentiation in response to ECTV infection. These results further our understanding of the mechanisms of CD4-CTL differentiation during viral infection and the role of posttranscriptionally regulated Runx3 in this process. <b>IMPORTANCE</b> While it is well established that cytotoxic CD4 T cells (CD4-CTLs) directly contribute to viral clearance, it remains unclear how CD4-CTL are induced. We now show that CD4-CTLs require sustained antigen presentation and are induced by CD11c-expressing antigen-presenting cells. Moreover, we show that CD4-CTLs are derived from the terminal differentiation of classical T helper 1 (Th1) subset of CD4 cells. Compared to Th1 cells, CD4-CTLs upregulate protein levels of the transcription factors ThPOK, Runx3, and GATA-3 posttranscriptionally. Deletion of Runx3 in differentiated CD4 T cells prevents induction of CD4-CTLs but not classical Th1 cells. These results advance our knowledge of how CD4-CTLs are induced during viral infection.","dates":{"release":"2021-01-01T00:00:00Z","publication":"2021 Sep","modification":"2025-05-18T12:32:08.646Z","creation":"2025-05-18T12:32:08.646Z"},"accession":"S-EPMC8428409","cross_references":{"pubmed":["34260270"],"doi":["10.1128/JVI.00566-21","10.1128/jvi.00566-21"]}}