RESUMO
Cytomegalovirus (CMV) infection has a life-long impact on the immune system, particularly on memory T cells. However, the effect of early life CMV infection on the phenotype and functionality of T cells in infants and especially longitudinal changes occurring during childhood have not been explored in detail. The phenotype and functionality of peripheral blood CD8+ and CD4+ T cells from children infected with CMV in early life (< 6 months of age) was analyzed using high-dimensional flow cytometry. Samples from CMV IgG-seropositive (CMV+) children were collected at 6 months and 6 years of age and compared to samples from CMV-seronegative (CMV-) children. Early life CMV infection caused multiple alterations within T cells. These include downregulation of CD28 expression and upregulation of CD57 expression within both CD27+ early and CD27- late effector memory CD8+ and CD4+ T-cells at 6 months of age. Of these changes, only alterations within the highly differentiated late effector memory compartment persisted at the age of 6 years. Early life CMV-infection has a distinct impact on developing CD8+ and CD4+ memory T cell compartments. It appears to induce both temporary as well as longer-lasting alterations, which may affect the functionality of the immune system throughout life.
Assuntos
Linfócitos T CD4-Positivos , Linfócitos T CD8-Positivos , Infecções por Citomegalovirus , Humanos , Infecções por Citomegalovirus/imunologia , Linfócitos T CD8-Positivos/imunologia , Lactente , Criança , Linfócitos T CD4-Positivos/imunologia , Feminino , Masculino , Citomegalovirus/imunologia , Membro 7 da Superfamília de Receptores de Fatores de Necrose Tumoral/imunologia , Membro 7 da Superfamília de Receptores de Fatores de Necrose Tumoral/metabolismo , Células T de Memória/imunologia , Antígenos CD28/imunologia , Antígenos CD28/metabolismo , Citometria de Fluxo , Antígenos CD57/imunologia , Antígenos CD57/metabolismo , Memória Imunológica/imunologia , Pré-Escolar , Imunoglobulina G/imunologia , Imunoglobulina G/sangueRESUMO
CD8+ T cells are perceived to play a major role in the pathogenesis of type 1 diabetes (T1D). In this study, we characterized the function and phenotype of circulating CD8+ memory T cells in samples from individuals at different stages of T1D progression using flow cytometry and single-cell multiomics. We observed two distinct CD8+ T-cell signatures during progression of T1D within the highly differentiated CD27-CD8+ memory T cell subset. A proinflammatory signature, with an increased frequency of IFN-γ+TNF-α+ CD27-CD8+ memory T cells, was observed in children with newly diagnosed T1D (stage 3) and correlated with the level of dysglycemia at diagnosis. In contrast, a co-inhibitory signature, with an increased frequency of KLRG1+TIGIT+ CD27-CD8+ memory T cells, was observed in islet autoantibody-positive children who later progressed to T1D (stage 1). No alterations within CD27-CD8+ memory T cells were observed in adults with established T1D or in children during the initial seroconversion to islet autoantibody positivity. Single-cell multiomics analyses suggested that CD27-CD8+ T cells expressing the IFNG+TNF+ proinflammatory signature may be distinct from those expressing the KLRG1+TIGIT+ co-inhibitory signature at the single-cell level. Collectively, our findings suggest that distinct blood CD8+ T-cell signatures could be employed as potential biomarkers of T1D progression.