Alexander Muselman

All Publications

• Erythropoietin receptor on cDC1s dictates immune tolerance. Nature Zhang, X., McGinnis, C. S., Yu, G., Chen, S., Zheng, P., Schürch, C. M., Hiam-Galvez, K. J., Reticker-Flynn, N. E., Guo, W., Yao, W., Qiu, J., Muselman, A., Linde, I. L., Hickey, J. W., Yan, H., Tran, V. M., Qiu, W., Brichart-Vernos, D., Hirai, T., Yu, B., An, X., Xiao, Y., Paidassi, H., Scharschmidt, T. C., Angelo, M., Sheppard, D., Chi, H., Satpathy, A. T., Way, S. S., Malissen, B., Strober, S., Engleman, E. G. 2025

  Abstract

  Type 1 conventional dendritic cells (cDC1s) are unique in their efferocytosis1 and cross-presenting abilities2, resulting in antigen-specific T cell immunity3 or tolerance4-8. However, the mechanisms that underlie cDC1 tolerogenic function remain largely unknown. Here we show that the erythropoietin receptor (EPOR) acts as a critical switch that determines the tolerogenic function of cDC1s and the threshold of antigen-specific T cell responses. In total lymphoid irradiation-induced allograft tolerance9,10, cDC1s upregulate EPOR expression, and conditional knockout of EPOR in cDC1s diminishes antigen-specific induction and expansion of FOXP3+ regulatory T (Treg) cells, resulting in allograft rejection. Mechanistically, EPOR promotes efferocytosis-induced tolerogenic maturation7,11 of splenic cDC1s towards late-stage CCR7+ cDC1s characterized by increased expression of the integrin β8 gene12 (Itgb8), and conditional knockout of Itgb8 in cDC1s impairs tolerance induced by total lymphoid irradiation plus anti-thymocyte serum. Migratory cDC1s in peripheral lymph nodes preferentially express EPOR, and their FOXP3+ Treg cell-inducing capacity is enhanced by erythropoietin. Reciprocally, loss of EPOR enables immunogenic maturation of peripheral lymph node migratory and splenic CCR7+ cDC1s by upregulating genes involved in MHC class II- and class I-mediated antigen presentation, cross-presentation and costimulation. EPOR deficiency in cDC1s reduces tumour growth by enhancing anti-tumour T cell immunity, particularly increasing the generation of precursor exhausted tumour antigen-specific CD8+ T cells13 in tumour-draining lymph nodes and supporting their maintenance within tumours, while concurrently reducing intratumoural Treg cells. Targeting EPOR on cDC1s to induce or inhibit T cell immune tolerance could have potential for treating a variety of diseases.

  View details for DOI 10.1038/s41586-025-09824-z

  View details for PubMedID 41372415

  View details for PubMedCentralID 10931539

• Early antiviral treatment following gammaherpesvirus-68 infection of the central nervous system prevents subsequent multiple sclerosis-like disease. Journal of neuroinflammation Muselman, A., Kongara, S., Hsu, N., Aggarwal, A., Yu, J., Rajadas, J., Engleman, E. G. 2025; 22 (1): 228

  Abstract

  Growing evidence indicates that Epstein-Barr virus (EBV), a gammaherpesvirus, plays a central role in the pathogenesis of multiple sclerosis (MS). The presence of EBV-infected cells in the central nervous system (CNS) of MS patients, but not in neurologically healthy individuals, suggests that viral persistence in the CNS may drive MS. However, why there is such a long interval between initial infection and the development of disease is unknown.To model the effects of EBV infection on the brain, we intracerebrally infected mice with murine gammaherpesvirus-68 (MHV68), a virus genetically related to EBV that causes transient pathology strikingly similar to that seen in humans after acute EBV infection. One month following MHV68 infection, we administered myelin oligodendrocyte glycoprotein (MOG) peptide to evaluate the effects of prior MHV68 infection on the response to an additional inflammatory stimulus of the CNS. Virus persistence, microglial activation and immune cell infiltration were evaluated over time using flow cytometry.Intracerebral MHV68 infection induced mild brain demyelination and ataxia, a common symptom of MS, that both quickly resolved. However, administration of MOG peptide one month later led to more severe brain demyelination and more sustained ataxia, suggesting that prior MHV68 infection sensitized the mice to a newly introduced immune stimulus. Further investigation revealed that following CNS infection, MHV68 persisted in microglia, where it induced a primed phenotype marked by elevated MHC-II expression and heightened immune reactivity for at least six months. Primed microglia displayed increases in the labile iron pool, and iron chelation reduced microglial priming. Early antiviral treatment during MHV68 infection completely prevented subsequent MOG-induced demyelinating disease.These findings support a two-step mechanism by which CNS infection with a gammaherpesvirus closely related to EBV sensitizes the host to a second unrelated immune stimulus that triggers MS-like disease manifestations. Chronic priming of microglia resulting from the initial infection contributes to this process, and prevention of such priming with early antiviral treatment also prevents neuropathology following the second stimulus. EBV infection may similarly sensitize humans to a second stimulus and, if so, treatment of acute EBV infection may avert subsequent MS development.

  View details for DOI 10.1186/s12974-025-03547-8

  View details for PubMedID 41063265

  View details for PubMedCentralID 5830904

• PD-1 directed immunotherapy alters Tfh and humoral immune responses to seasonal influenza vaccine. Nature immunology Herati, R. S., Knorr, D. A., Vella, L. A., Silva, L. V., Chilukuri, L., Apostolidis, S. A., Huang, A. C., Muselman, A., Manne, S., Kuthuru, O., Staupe, R. P., Adamski, S. A., Kannan, S., Kurupati, R. K., Ertl, H. C., Wong, J. L., Bournazos, S., McGettigan, S., Schuchter, L. M., Kotecha, R. R., Funt, S. A., Voss, M. H., Motzer, R. J., Lee, C., Bajorin, D. F., Mitchell, T. C., Ravetch, J. V., Wherry, E. J. 2022

  Abstract

  Anti-programmed death-1 (anti-PD-1) immunotherapy reinvigorates CD8 T cell responses in patients with cancer but PD-1 is also expressed by other immune cells, including follicular helper CD4 T cells (Tfh) which are involved in germinal centre responses. Little is known, however, about the effects of anti-PD-1 immunotherapy on noncancer immune responses in humans. To investigate this question, we examined the impact of anti-PD-1 immunotherapy on the Tfh-B cell axis responding to unrelated viral antigens. Following influenza vaccination, a subset of adults receiving anti-PD-1 had more robust circulating Tfh responses than adults not receiving immunotherapy. PD-1 pathway blockade resulted in transcriptional signatures of increased cellular proliferation in circulating Tfh and responding B cells compared with controls. These latter observations suggest an underlying change in the Tfh-B cell and germinal centre axis in a subset of immunotherapy patients. Together, these results demonstrate dynamic effects of anti-PD-1 therapy on influenza vaccine responses and highlight analytical vaccination as an approach that may reveal underlying immune predisposition to adverse events.

  View details for DOI 10.1038/s41590-022-01274-3

  View details for PubMedID 35902637

• T follicular helper cells in human efferent lymph retain lymphoid characteristics JOURNAL OF CLINICAL INVESTIGATION Vella, L. A., Buggert, M., Manne, S., Herati, R. S., Sayin, I., Kuri-Cervantes, L., Brody, I., O'Boyle, K. C., Kaprielian, H., Giles, J. R., Nguyen, S., Muselman, A., Antel, J. P., Bar-Or, A., Johnson, M. E., Canaday, D. H., Naji, A., Ganusov, V. V., Laufer, T. M., Wells, A. D., Dori, Y., Itkin, M. G., Betts, M. R., Wherry, E. 2019; 129 (8): 3185-3200

  Abstract

  T follicular helper cells (Tfh), a subset of CD4+ T cells, provide requisite help to B cells in the germinal centers (GC) of lymphoid tissue. GC Tfh are identified by high expression of the chemokine receptor CXCR5 and the inhibitory molecule PD-1. Although more accessible, blood contains lower frequencies of CXCR5+ and PD-1+ cells that have been termed circulating Tfh (cTfh). However, it remains unclear whether GC Tfh exit lymphoid tissues and populate this cTfh pool. To examine exiting cells, we assessed the phenotype of Tfh present within the major conduit of efferent lymph from lymphoid tissues into blood, the human thoracic duct. Unlike what was found in blood, we consistently identified a CXCR5-bright PD-1-bright (CXCR5BrPD-1Br) Tfh population in thoracic duct lymph (TDL). These CXCR5BrPD-1Br TDL Tfh shared phenotypic and transcriptional similarities with GC Tfh. Moreover, components of the epigenetic profile of GC Tfh could be detected in CXCR5BrPD-1Br TDL Tfh and the transcriptional imprint of this epigenetic signature was enriched in an activated cTfh subset known to contain vaccine-responding cells. Together with data showing shared TCR sequences between the CXCR5BrPD-1Br TDL Tfh and cTfh, these studies identify a population in TDL as a circulatory intermediate connecting the biology of Tfh in blood to Tfh in lymphoid tissue.

  View details for DOI 10.1172/JCI125628

  View details for Web of Science ID 000478076500024

  View details for PubMedID 31264971

  View details for PubMedCentralID PMC6668682

• Successive annual influenza vaccination induces a recurrent oligoclonotypic memory response in circulating T follicular helper cells SCIENCE IMMUNOLOGY Herati, R., Muselman, A., Vella, L., Bengsch, B., Parkhouse, K., Del Alcazar, D., Kotzin, J., Doyle, S. A., Tebas, P., Hensley, S. E., Su, L. F., Schmader, K. E., Wherry, E. 2017; 2 (8)

  Abstract

  T follicular helper (Tfh) CD4 cells are crucial providers of B cell help during adaptive immune responses. A circulating population of CD4 T cells, termed cTfh, have similarity to lymphoid Tfh, can provide B cell help, and responded to influenza vaccination. However, it is unclear whether human vaccination-induced cTfh respond in an antigen-specific manner and whether they form long-lasting memory. Here, we identified a cTfh population that expressed multiple T cell activation markers and could be readily identified by coexpression of ICOS and CD38. This subset expressed more Bcl-6, c-Maf, and IL-21 than other blood CD4 subsets. Influenza vaccination induced a strong response in the ICOS+CD38+ cTfh at day 7, and this population included hemagglutinin-specific cells by tetramer staining and antigen-stimulated Activation Induced Marker (AIM) expression. Moreover, TCRB sequencing identified a clonal response in ICOS+CD38+ cTfh that correlated strongly with the increased circulating ICOS+CD38+ cTfh frequency and the circulating plasmablast response. In subjects who received successive annual vaccinations, a recurrent oligoclonal response was identified in the ICOS+CD38+ cTfh subset at 7 days after every vaccination. These oligoclonal responses in ICOS+CD38+ cTfh after vaccination persisted in the ICOS-CD38- cTfh repertoire in subsequent years, suggesting clonal maintenance in a memory reservoir in the more-stable ICOS-CD38- cTfh subset. These data highlight the antigen-specificity, lineage relationships and memory properties of human cTfh responses to vaccination, providing new avenues for tracking and monitoring cTfh responses during infection and vaccination in humans.

  View details for DOI 10.1126/sciimmunol.aag2152

  View details for Web of Science ID 000434310300002

  View details for PubMedID 28620653

  View details for PubMedCentralID PMC5469419

• Loss of RUNX1 function results in enhanced granulocyte-colony-stimulating factor-mediated mobilization BLOOD CANCER JOURNAL Lam, K., Muselman, A., Du, R., Yan, M., Matsuura, S., Zhang, D. 2016; 6: e407

  View details for DOI 10.1038/bcj.2016.20

  View details for Web of Science ID 000373142400007

  View details for PubMedID 27015284

  View details for PubMedCentralID PMC4817102

• <i>Hmga2</i> is a direct target gene of RUNX1 and regulates expansion of myeloid progenitors in mice BLOOD Lam, K., Muselman, A., Du, R., Harada, Y., Scholl, A. G., Yan, M., Matsuura, S., Weng, S., Harada, H., Zhang, D. 2014; 124 (14): 2203-2212

  Abstract

  RUNX1 is a master transcription factor in hematopoiesis and mediates the specification and homeostasis of hematopoietic stem and progenitor cells (HSPCs). Disruptions in RUNX1 are well known to lead to hematologic disease. In this study, we sought to identify and characterize RUNX1 target genes in HSPCs by performing RUNX1 chromatin immunoprecipitation with high-throughput sequencing (ChIP-seq) using a murine HSPC line and complementing this data with our previously described gene expression profiling of primary wild-type and RUNX1-deficient HSPCs (Lineage(-)/cKit(+)/Sca1(+)). From this analysis, we identified and confirmed that Hmga2, a known oncogene, as a direct target of RUNX1. Hmga2 was strongly upregulated in RUNX1-deficient HSPCs, and the promoter of Hmga2 was responsive in a cell-type dependent manner upon coexpression of RUNX1. Conditional Runx1 knockout mice exhibit expansion of their HSPCs and myeloid progenitors as hallmark phenotypes. To further validate and establish that Hmga2 plays a role in inducing HSPC expansion, we generated mouse models of HMGA2 and RUNX1 deficiency. Although mice lacking both factors continued to display higher frequencies of HSPCs, the expansion of myeloid progenitors was effectively rescued. The data presented here establish Hmga2 as a transcriptional target of RUNX1 and a critical regulator of myeloid progenitor expansion.

  View details for DOI 10.1182/blood-2014-02-554543

  View details for Web of Science ID 000342763900013

  View details for PubMedID 25150295

  View details for PubMedCentralID PMC4183983