Integrative Proteomics and Phosphoproteomics Profiling Reveals Dynamic Signaling Networks and Bioenergetics Pathways Underlying T Cell Activation.

The molecular circuits by which antigens activate quiescent T cells remain poorly understood. We combined temporal profiling of the whole proteome and phosphoproteome via multiplexed isobaric labeling proteomics technology, computational pipelines for integrating multi-omics datasets, and functional perturbation to systemically reconstruct regulatory networks underlying T cell activation. T cell receptors activated the T cell proteome and phosphoproteome with discrete kinetics, marked by early dynamics of phosphorylation and delayed ribosome biogenesis and mitochondrial activation. Systems biology analyses identified multiple functional modules, active kinases, transcription factors and connectivity between them, and mitochondrial pathways including mitoribosomes and complex IV. Genetic perturbation revealed physiological roles for mitochondrial enzyme COX10-mediated oxidative phosphorylation in T cell quiescence exit. Our multi-layer proteomics profiling, integrative network analysis, and functional studies define landscapes of the T cell proteome and phosphoproteome and reveal signaling and bioenergetics pathways that mediate lymphocyte exit from quiescence.

Homeostatic control of metabolic and functional fitness of Treg cells by LKB1 signalling.

Regulatory T cells (Treg cells) have a pivotal role in the establishment and maintenance of immunological self-tolerance and homeostasis. Transcriptional programming of regulatory mechanisms facilitates the functional activation of Treg cells in the prevention of diverse types of inflammatory responses. It remains unclear how Treg cells orchestrate their homeostasis and interplay with environmental signals. Here we show that liver kinase B1 (LKB1) programs the metabolic and functional fitness of Treg cells in the control of immune tolerance and homeostasis. Mice with a Treg-specific deletion of LKB1 developed a fatal inflammatory disease characterized by excessive TH2-type-dominant responses. LKB1 deficiency disrupted Treg cell survival and mitochondrial fitness and metabolism, but also induced aberrant expression of immune regulatory molecules including the negative co-receptor PD-1 and the TNF receptor superfamily proteins GITR and OX40. Unexpectedly, LKB1 function in Treg cells was independent of conventional AMPK signalling or the mTORC1-HIF-1α axis, but contributed to the activation of ß-catenin signalling for the control of PD-1 and TNF receptor proteins. Blockade of PD-1 activity reinvigorated the ability of LKB1-deficient Treg cells to suppress TH2 responses and the interplay with dendritic cells primed by thymic stromal lymphopoietin. Thus, Treg cells use LKB1 signalling to coordinate their metabolic and immunological homeostasis and to prevent apoptotic and functional exhaustion, thereby orchestrating the balance between immunity and tolerance.

Collaboration for success: the Global Initiative for Childhood Cancer in Latin America.

The Global Initiative for Childhood Cancer (GICC) aims to increase the cure rate for children with cancer globally by improving healthcare access and quality. The Pan American Health Organization (PAHO), St. Jude Children's Research Hospital (St. Jude), and collaborators have joined efforts to improve outcomes of children with cancer in Latin America and the Caribbean (LAC) using the CureAll framework. In this article, we describe the process of developing regional resources aimed at accelerating the GICC implementation in LAC. In March 2021, PAHO formed regional working groups to develop core projects aligned with CureAll pillars and enablers. Seven working groups emerged from regional dialogues: early detection, nursing, psychosocial, nutrition, supportive care, treatment abandonment, and palliative care. PAHO arranged regular online meetings under the mentorship and support of St. Jude regional/transversal programs and international mentors. Between April and December 2021, 202 multidisciplinary experts attended 43 online meetings to promote the dialogue between stakeholders to improve childhood cancer outcomes. Fourteen technical outputs were produced: four regional snapshots, four technical documents, two virtual courses, one set of epidemiological country profiles, one educational content series for parents/caregivers, and two communication campaigns. The ongoing dialogue and commitment of PAHO, St. Jude, LAC working committees, and international collaborators are essential foundations to successfully accelerate GICC implementation. This is achievable through the development of materials of regional and global relevance. Further research and evaluation are needed to determine the impact of these strategies and resources on childhood cancer outcomes in LAC and other regions.

La Iniciativa Mundial contra el Cáncer Infantil tiene como objetivo aumentar a nivel mundial la tasa de curación del cáncer infantil mediante la mejora del acceso a la atención de salud y de su calidad. La Organización Panamericana de la Salud (OPS), el St. Jude Children's Research Hospital y los colaboradores han aunado esfuerzos para mejorar los resultados en la población infantil con cáncer en América Latina y el Caribe valiéndose del marco CureAll. En este artículo describimos el proceso de elaboración de recursos regionales destinados a acelerar la aplicación de la Iniciativa Mundial en América Latina y el Caribe.En marzo del 2021, la OPS formó grupos de trabajo regionales para elaborar proyectos básicos que estuvieran en consonancia con los pilares y los elementos facilitadores del CureAll. De los diálogos regionales surgieron siete grupos de trabajo: detección temprana, enfermería, aspectos psicosociales, nutrición, tratamientos de apoyo, abandono del tratamiento y cuidados paliativos. La OPS organizó con regularidad reuniones virtuales en las que se contó con la tutoría y el apoyo de programas regionales o transversales del St. Jude Children's Research Hospital y de mentores internacionales.Entre abril y diciembre del 2021 hubo 43 reuniones virtuales a las que asistieron 202 expertos multidisciplinarios, con el objetivo de promover el diálogo entre las partes interesadas para mejorar los resultados en materia de cáncer infantil. Se elaboraron catorce productos técnicos: cuatro panoramas regionales, cuatro documentos técnicos, dos cursos virtuales, un conjunto de perfiles epidemiológicos de países, una serie con contenidos educativos para padres y cuidadores y dos campañas de comunicación.El diálogo y el compromiso constantes de la OPS, el St. Jude Children's Research Hospital, los comités de trabajo de América Latina y el Caribe y los colaboradores internacionales son las bases fundamentales para conseguir que se acelere la aplicación de la Iniciativa Mundial. Esto se puede lograr mediante la elaboración de materiales que resulten pertinentes a nivel regional y mundial. Son necesarias más investigaciones y evaluaciones para determinar el impacto que tienen estas estrategias y recursos en los resultados que se obtienen en el cáncer infantil en América Latina y el Caribe y en otras subregiones.

A Iniciativa Global para o Câncer Infantil tem como objetivo aumentar a taxa de cura de crianças com câncer no mundo todo, melhorando o acesso a cuidados e a qualidade da assistência médica. A Organização Pan-Americana da Saúde (OPAS), o St. Jude Children's Research Hospital (St. Jude) e colaboradores uniram esforços para melhorar o desfecho de crianças com câncer na América Latina e no Caribe (ALC) no âmbito do marco CureAll. Neste artigo, descrevemos o processo de desenvolvimento de recursos regionais com o objetivo de acelerar a implementação da Iniciativa na ALC.Em março de 2021, a OPAS formou grupos de trabalho regionais para desenvolver projetos centrais alinhados com os pilares e facilitadores do CureAll. A partir das reuniões de diálogo regionais, foram criados sete grupos de trabalho: detecção precoce, enfermagem, atenção psicossocial, nutrição, cuidados de suporte, abandono do tratamento e cuidados paliativos. A OPAS organizou reuniões virtuais regulares sob a orientação e o apoio dos programas regionais e transversais do St. Jude e de mentores internacionais.Entre abril e dezembro de 2021, 202 especialistas multidisciplinares participaram de 43 reuniões virtuais para promover o diálogo entre as partes interessadas a fim de melhorar os desfechos do câncer infantil. Foram produzidos 14 materiais técnicos: quatro panoramas regionais, quatro documentos técnicos, dois cursos virtuais, um conjunto de perfis epidemiológicos nacionais, uma série de conteúdo educacional para pais e cuidadores e duas campanhas de comunicação.O diálogo e o compromisso contínuos da OPAS, do St. Jude, dos comitês de trabalho da ALC e dos colaboradores internacionais são bases essenciais para acelerar com sucesso a implementação da Iniciativa Global para o Câncer Infantil. Isso é possível por meio do desenvolvimento de materiais de relevância regional e mundial. São necessárias mais pesquisas e avaliações para determinar o impacto dessas estratégias e recursos nos resultados do câncer infantil na ALC e em outras regiões.

PTEN directs developmental and metabolic signaling for innate-like T cell fate and tissue homeostasis.

Phosphatase and tensin homologue (PTEN) is frequently mutated in human cancer, but its roles in lymphopoiesis and tissue homeostasis remain poorly defined. Here we show that PTEN orchestrates a two-step developmental process linking antigen receptor and IL-23-Stat3 signalling to type-17 innate-like T cell generation. Loss of PTEN leads to pronounced accumulation of mature IL-17-producing innate-like T cells in the thymus. IL-23 is essential for their accumulation, and ablation of IL-23 or IL-17 signalling rectifies the reduced survival of female PTEN-haploinsufficient mice that model human patients with PTEN mutations. Single-cell transcriptome and network analyses revealed the dynamic regulation of PTEN, mTOR and metabolic activities that accompanied type-17 cell programming. Furthermore, deletion of mTORC1 or mTORC2 blocks PTEN loss-driven type-17 cell accumulation, and this is further shaped by the Foxo1 and Stat3 pathways. Collectively, our study establishes developmental and metabolic signalling networks underpinning type-17 cell fate decisions and their functional effects at coordinating PTEN-dependent tissue homeostasis.

Quantifying Proteome and Protein Modifications in Activated T Cells by Multiplexed Isobaric Labeling Mass Spectrometry.

The dynamic regulation of protein function by altered protein expression and post-translational modifications (PTMs) is essential for T cell function, but it has remained difficult to systemically quantify such events. Mass spectrometry (MS)-based proteomics has become a mainstream tool for comprehensive profiling of proteome and PTMs, especially with the development of multiplexed isobaric labeling methods, such as tandem mass tag (TMT), coupled with high-resolution two-dimensional liquid chromatography and tandem mass spectrometry (LC/LC-MS/MS). Here, we introduce a deep proteomics profiling protocol with an optimized 11-plex TMT-LC/LC-MS/MS platform to quantitate whole proteome, phosphoproteome, acetylome, and methylome in activated T cells. The major steps include preparation of activated T cells, protein extraction and digestion, TMT labeling, basic pH reverse phase LC, modified peptide enrichment, acidic pH reverse phase LC-MS/MS, and computational data processing. Approximately 10,000 proteins, 30,000 phosphosites, 2,000 lysine acetylated sites, and 1,000 lysine methylated sites can be identified and quantified from 1 mg of proteins per sample. Quality control steps are implemented in this protocol, and future development, such as nanoscale 16-plex TMT analysis, is discussed. This multiplexed and robust method provides a powerful tool for dissecting proteomic and PTM signatures in T cells at the systems level, and it is equally suitable for other biological samples, including effector T cell subsets.

Metabolic signaling directs the reciprocal lineage decisions of αß and γδ T cells.

The interaction between extrinsic factors and intrinsic signal strength governs thymocyte development, but the mechanisms linking them remain elusive. We report that mechanistic target of rapamycin complex 1 (mTORC1) couples microenvironmental cues with metabolic programs to orchestrate the reciprocal development of two fundamentally distinct T cell lineages, the αß and γδ T cells. Developing thymocytes dynamically engage metabolic programs including glycolysis and oxidative phosphorylation, as well as mTORC1 signaling. Loss of RAPTOR-mediated mTORC1 activity impairs the development of αß T cells but promotes γδ T cell generation, associated with disrupted metabolic remodeling of oxidative and glycolytic metabolism. Mechanistically, we identify mTORC1-dependent control of reactive oxygen species production as a key metabolic signal in mediating αß and γδ T cell development, and perturbation of redox homeostasis impinges upon thymocyte fate decisions and mTORC1-associated phenotypes. Furthermore, single-cell RNA sequencing and genetic dissection reveal that mTORC1 links developmental signals from T cell receptors and NOTCH to coordinate metabolic activity and signal strength. Our results establish mTORC1-driven metabolic signaling as a decisive factor for reciprocal αß and γδ T cell development and provide insight into metabolic control of cell signaling and fate decisions.

Collaboration for success: the Global Initiative for Childhood Cancer in Latin America / Colaborar para tener éxito: la Iniciativa Mundial contra el Cáncer Infantil en América Latina / Colaboração para o sucesso: a Iniciativa Global para o Câncer Infantil na América Latina

ABSTRACT The Global Initiative for Childhood Cancer (GICC) aims to increase the cure rate for children with cancer globally by improving healthcare access and quality. The Pan American Health Organization (PAHO), St. Jude Children's Research Hospital (St. Jude), and collaborators have joined efforts to improve outcomes of children with cancer in Latin America and the Caribbean (LAC) using the CureAll framework. In this article, we describe the process of developing regional resources aimed at accelerating the GICC implementation in LAC. In March 2021, PAHO formed regional working groups to develop core projects aligned with CureAll pillars and enablers. Seven working groups emerged from regional dialogues: early detection, nursing, psychosocial, nutrition, supportive care, treatment abandonment, and palliative care. PAHO arranged regular online meetings under the mentorship and support of St. Jude regional/transversal programs and international mentors. Between April and December 2021, 202 multidisciplinary experts attended 43 online meetings to promote the dialogue between stakeholders to improve childhood cancer outcomes. Fourteen technical outputs were produced: four regional snapshots, four technical documents, two virtual courses, one set of epidemiological country profiles, one educational content series for parents/caregivers, and two communication campaigns. The ongoing dialogue and commitment of PAHO, St. Jude, LAC working committees, and international collaborators are essential foundations to successfully accelerate GICC implementation. This is achievable through the development of materials of regional and global relevance. Further research and evaluation are needed to determine the impact of these strategies and resources on childhood cancer outcomes in LAC and other regions.

RESUMEN La Iniciativa Mundial contra el Cáncer Infantil tiene como objetivo aumentar a nivel mundial la tasa de curación del cáncer infantil mediante la mejora del acceso a la atención de salud y de su calidad. La Organización Panamericana de la Salud (OPS), el St. Jude Children's Research Hospital y los colaboradores han aunado esfuerzos para mejorar los resultados en la población infantil con cáncer en América Latina y el Caribe valiéndose del marco CureAll. En este artículo describimos el proceso de elaboración de recursos regionales destinados a acelerar la aplicación de la Iniciativa Mundial en América Latina y el Caribe. En marzo del 2021, la OPS formó grupos de trabajo regionales para elaborar proyectos básicos que estuvieran en consonancia con los pilares y los elementos facilitadores del CureAll. De los diálogos regionales surgieron siete grupos de trabajo: detección temprana, enfermería, aspectos psicosociales, nutrición, tratamientos de apoyo, abandono del tratamiento y cuidados paliativos. La OPS organizó con regularidad reuniones virtuales en las que se contó con la tutoría y el apoyo de programas regionales o transversales del St. Jude Children's Research Hospital y de mentores internacionales. Entre abril y diciembre del 2021 hubo 43 reuniones virtuales a las que asistieron 202 expertos multidisciplinarios, con el objetivo de promover el diálogo entre las partes interesadas para mejorar los resultados en materia de cáncer infantil. Se elaboraron catorce productos técnicos: cuatro panoramas regionales, cuatro documentos técnicos, dos cursos virtuales, un conjunto de perfiles epidemiológicos de países, una serie con contenidos educativos para padres y cuidadores y dos campañas de comunicación. El diálogo y el compromiso constantes de la OPS, el St. Jude Children's Research Hospital, los comités de trabajo de América Latina y el Caribe y los colaboradores internacionales son las bases fundamentales para conseguir que se acelere la aplicación de la Iniciativa Mundial. Esto se puede lograr mediante la elaboración de materiales que resulten pertinentes a nivel regional y mundial. Son necesarias más investigaciones y evaluaciones para determinar el impacto que tienen estas estrategias y recursos en los resultados que se obtienen en el cáncer infantil en América Latina y el Caribe y en otras subregiones.

RESUMO A Iniciativa Global para o Câncer Infantil tem como objetivo aumentar a taxa de cura de crianças com câncer no mundo todo, melhorando o acesso a cuidados e a qualidade da assistência médica. A Organização Pan-Americana da Saúde (OPAS), o St. Jude Children's Research Hospital (St. Jude) e colaboradores uniram esforços para melhorar o desfecho de crianças com câncer na América Latina e no Caribe (ALC) no âmbito do marco CureAll. Neste artigo, descrevemos o processo de desenvolvimento de recursos regionais com o objetivo de acelerar a implementação da Iniciativa na ALC. Em março de 2021, a OPAS formou grupos de trabalho regionais para desenvolver projetos centrais alinhados com os pilares e facilitadores do CureAll. A partir das reuniões de diálogo regionais, foram criados sete grupos de trabalho: detecção precoce, enfermagem, atenção psicossocial, nutrição, cuidados de suporte, abandono do tratamento e cuidados paliativos. A OPAS organizou reuniões virtuais regulares sob a orientação e o apoio dos programas regionais e transversais do St. Jude e de mentores internacionais. Entre abril e dezembro de 2021, 202 especialistas multidisciplinares participaram de 43 reuniões virtuais para promover o diálogo entre as partes interessadas a fim de melhorar os desfechos do câncer infantil. Foram produzidos 14 materiais técnicos: quatro panoramas regionais, quatro documentos técnicos, dois cursos virtuais, um conjunto de perfis epidemiológicos nacionais, uma série de conteúdo educacional para pais e cuidadores e duas campanhas de comunicação. O diálogo e o compromisso contínuos da OPAS, do St. Jude, dos comitês de trabalho da ALC e dos colaboradores internacionais são bases essenciais para acelerar com sucesso a implementação da Iniciativa Global para o Câncer Infantil. Isso é possível por meio do desenvolvimento de materiais de relevância regional e mundial. São necessárias mais pesquisas e avaliações para determinar o impacto dessas estratégias e recursos nos resultados do câncer infantil na ALC e em outras regiões.

Collaboration for success: the Global Initiative for Childhood Cancer in Latin America / Colaborar para tener éxito: la Iniciativa Mundial contra el Cáncer Infantil en América Latina / Colaboração para o sucesso: a Iniciativa Global para o Câncer Infantil na América Latina

[ABSTRACT]. The Global Initiative for Childhood Cancer (GICC) aims to increase the cure rate for children with cancer globally by improving healthcare access and quality. The Pan American Health Organization (PAHO), St. Jude Children’s Research Hospital (St. Jude), and collaborators have joined efforts to improve outcomes of children with cancer in Latin America and the Caribbean (LAC) using the CureAll framework. In this article, we describe the process of developing regional resources aimed at accelerating the GICC implementation in LAC. In March 2021, PAHO formed regional working groups to develop core projects aligned with CureAll pillars and enablers. Seven working groups emerged from regional dialogues: early detection, nursing, psychosocial, nutrition, supportive care, treatment abandonment, and palliative care. PAHO arranged regular online meetings under the mentorship and support of St. Jude regional/transversal programs and international mentors. Between April and December 2021, 202 multidisciplinary experts attended 43 online meetings to promote the dialogue between stakeholders to improve childhood cancer outcomes. Fourteen technical outputs were produced: four regional snapshots, four technical documents, two virtual courses, one set of epidemiological country profiles, one educational content series for parents/caregivers, and two communication campaigns. The ongoing dialogue and commitment of PAHO, St. Jude, LAC working committees, and international collaborators are essential foundations to successfully accelerate GICC implementation. This is achievable through the development of materials of regional and global relevance. Further research and evaluation are needed to deter- mine the impact of these strategies and resources on childhood cancer outcomes in LAC and other regions.

[RESUMEN]. La Iniciativa Mundial contra el Cáncer Infantil tiene como objetivo aumentar a nivel mundial la tasa de curación del cáncer infantil mediante la mejora del acceso a la atención de salud y de su calidad. La Organización Panamericana de la Salud (OPS), el St. Jude Children’s Research Hospital y los colaboradores han aunado esfuerzos para mejorar los resultados en la población infantil con cáncer en América Latina y el Caribe valiéndose del marco CureAll. En este artículo describimos el proceso de elaboración de recursos regionales destinados a acelerar la aplicación de la Iniciativa Mundial en América Latina y el Caribe. En marzo del 2021, la OPS formó grupos de trabajo regionales para elaborar proyectos básicos que estuvieran en consonancia con los pilares y los elementos facilitadores del CureAll. De los diálogos regionales surgieron siete grupos de trabajo: detección temprana, enfermería, aspectos psicosociales, nutrición, tratamientos de apoyo, abandono del tratamiento y cuidados paliativos. La OPS organizó con regularidad reuniones virtuales en las que se contó con la tutoría y el apoyo de programas regionales o transversales del St. Jude Children’s Research Hospital y de mentores internacionales. Entre abril y diciembre del 2021 hubo 43 reuniones virtuales a las que asistieron 202 expertos multidisciplinarios, con el objetivo de promover el diálogo entre las partes interesadas para mejorar los resultados en materia de cáncer infantil. Se elaboraron catorce productos técnicos: cuatro panoramas regionales, cuatro documentos técnicos, dos cursos virtuales, un conjunto de perfiles epidemiológicos de países, una serie con contenidos educativos para padres y cuidadores y dos campañas de comunicación. El diálogo y el compromiso constantes de la OPS, el St. Jude Children’s Research Hospital, los comités de trabajo de América Latina y el Caribe y los colaboradores internacionales son las bases fundamentales para conseguir que se acelere la aplicación de la Iniciativa Mundial. Esto se puede lograr mediante la elaboración de materiales que resulten pertinentes a nivel regional y mundial. Son necesarias más investigaciones y evaluaciones para determinar el impacto que tienen estas estrategias y recursos en los resultados que se obtienen en el cáncer infantil en América Latina y el Caribe y en otras subregiones.

[RESUMO]. A Iniciativa Global para o Câncer Infantil tem como objetivo aumentar a taxa de cura de crianças com câncer no mundo todo, melhorando o acesso a cuidados e a qualidade da assistência médica. A Organização Pan-Americana da Saúde (OPAS), o St. Jude Children's Research Hospital (St. Jude) e colaboradores uniram esforços para melhorar o desfecho de crianças com câncer na América Latina e no Caribe (ALC) no âmbito do marco CureAll. Neste artigo, descrevemos o processo de desenvolvimento de recursos regionais com o objetivo de acelerar a implementação da Iniciativa na ALC. Em março de 2021, a OPAS formou grupos de trabalho regionais para desenvolver projetos centrais alinha- dos com os pilares e facilitadores do CureAll. A partir das reuniões de diálogo regionais, foram criados sete grupos de trabalho: detecção precoce, enfermagem, atenção psicossocial, nutrição, cuidados de suporte, abandono do tratamento e cuidados paliativos. A OPAS organizou reuniões virtuais regulares sob a orientação e o apoio dos programas regionais e transversais do St. Jude e de mentores internacionais. Entre abril e dezembro de 2021, 202 especialistas multidisciplinares participaram de 43 reuniões virtuais para promover o diálogo entre as partes interessadas a fim de melhorar os desfechos do câncer infantil. Foram produzidos 14 materiais técnicos: quatro panoramas regionais, quatro documentos técnicos, dois cursos virtuais, um conjunto de perfis epidemiológicos nacionais, uma série de conteúdo educacional para pais e cuidadores e duas campanhas de comunicação. O diálogo e o compromisso contínuos da OPAS, do St. Jude, dos comitês de trabalho da ALC e dos colabora- dores internacionais são bases essenciais para acelerar com sucesso a implementação da Iniciativa Global para o Câncer Infantil. Isso é possível por meio do desenvolvimento de materiais de relevância regional e mundial. São necessárias mais pesquisas e avaliações para determinar o impacto dessas estratégias e recursos nos resultados do câncer infantil na ALC e em outras regiões.

Modulation of Immune response by Ultra-violet light in HLA class-II transgenic mice.

Multiple Sclerosis (MS) is a chronic and debilitating disease of the central nervous system linked to both genetic and environmental factors. Among the genetic factors, MHC, especially HLA class-II, is strongly associated with predisposition to MS. Although in vitro studies have helped us understand some aspects of HLA class-II association with the disease, performing in vivo analysis is necessary in order to further understand this correlation. Studying the role of class-II genes in vivo is a difficult task due to the heterogeneity of human population, the complexity of MHC, and the strong linkage disequilibrium among different class-II genes. To overcome this challenge, we generated HLA class-II transgenic mice to study the role of these molecules in MS. Among the environmental factors linked with MS, ultra violet radiation (UVR)/vitamin-D is suggested to have protective effect against the development of the disease. Indeed, genetic studies have shown that presence of susceptible HLA-Class II and decrease in UVR exposure or vitamin D levels together increase risk of MS. Therefore, this study was designed to investigate the direct effect of UVR on immune response using novel humanized HLA-class II transgenic mice. HLA-class II transgenic mice expressing MS susceptible HLA-DR2 allele were treated with different doses of UVR (0.50-3.75 kJ/day) for seven consecutive days. T-cell proliferation, immune cell sub-populations and cytokines levels were analyzed. Our results show that treatment with UVR increased levels of regulatory CD4+FoxP3+ T cells and Gr1+ CD11b+ suppressive macrophages. Thus our study indicates that UVR modulates the immune response towards a tolerogenic phenotype in HLA-transgenic mice immunized with MOG35-55. Therefore, HLA class-II transgenic mice offer a novel tool to decipher the mechanism by which interaction between environmental and genetic factors play a role in predisposition and/or protection against development of MS.