RESUMO
Adaptive immunity and T cell function are affected by aging. Calcium influx patterns, regulated by Kv1.3 and IKCa1 potassium channels, influence T cell activation. We aimed to compare calcium influx kinetics in CD8, Th1 and Th2 cells in human peripheral blood samples obtained from five different age groups (cord blood, 10-15 ys, 25-40 ys, 45-55 ys, 60-75 ys).We measured calcium influx using flow cytometry in samples treated with or without specific inhibitors of Kv1.3 and IKCa1 channels (MGTX and TRAM, respectively).Calcium influx was higher in Th1 cells of adults, however, its extent decreased again with aging. Importantly, these changes were not detected in Th2 cells, where the pattern of calcium influx kinetics is similar throughout all investigated age groups. MGTX had a more pronounced inhibitory effect on calcium influx in Th2 cells, while in Th1 cells the same was true for TRAM in the 25-40 ys and 45-55 ys groups. Calcium influx of CD8 cells were inhibited to a similar extent by both applied inhibitors in these groups, and had no effect in the elderly.Altered lymphocyte potassium channel inhibitory patterns, regulators of calcium influx kinetics, might contribute to the development of age-related changes of T cell function.
Assuntos
Cálcio/sangue , Sangue Fetal/metabolismo , Canais de Potássio/sangue , Linfócitos T/metabolismo , Adolescente , Adulto , Fatores Etários , Idoso , Linfócitos T CD8-Positivos/imunologia , Linfócitos T CD8-Positivos/metabolismo , Criança , Feminino , Sangue Fetal/citologia , Humanos , Recém-Nascido , Ativação Linfocitária , Masculino , Pessoa de Meia-Idade , Linfócitos T/imunologia , Células Th1/imunologia , Células Th1/metabolismo , Células Th2/imunologia , Células Th2/metabolismo , Adulto JovemRESUMO
Umbilical cord blood (UCB) is a promising alternative for the treatment of hematological malignancies. The lower immune reactivity of UCB lymphocytes is a well-known phenomenon; however, immune tolerance mechanisms are not fully elucidated. Galectin-1 has strong immunosuppressive properties and plays a key role in the regulation of immune reactivity. We aimed to determine the properties of intracellular galectin-1 (Gal-1)-producing cells within CD3, CD4, CD8, regulatory T (Treg), and natural killer (NK) cells in UCB compared to adult peripheral blood (APB). We took peripheral blood samples from 22 healthy adults and cord blood samples from 19 healthy, term neonates. Intracellular Gal-1 expression was determined by flow cytometry in the above subsets. Furthermore, we assessed the prevalence of naive and memory T cells that play a role in the regulation of immune reactivity. We also performed functional analyses to assess the effect of exogenous Gal-1 on the rate of proliferation of T lymphocytes isolated from APB and UCB. The prevalence of intracellular Gal-1-expressing CD3, CD4, CD8, Treg and NK lymphocytes was lower in UCB than in APB. However, their capability to produce Gal-1 reaches the level seen in adults. The prevalence of naive cells was higher, whereas that of central and effector memory T cells was lower in UCB compared with APB. Lower Gal-1-producing cell proportion might be due to the naivety of neonatal lymphocytes, as indicated by the positive correlation detected between the number of CD3 lymphocytes expressing intracellular Gal-1 and the prevalence of memory T cells. The intracellular expression of Gal-1 may be down-regulated in neonatal lymphocytes due to the already reduced immune reactivity of UCB. In contrast with previous findings, our results indicate that the administration of exogenous Gal-1 failed to decrease the rate of proliferation in T lymphocytes isolated from either APB or UCB. This suggests that Gal-1-expressing lymphocytes are unlikely to play a major role in mitigating the immune reactivity of UCB.
Assuntos
Linfócitos T CD8-Positivos/metabolismo , Sangue Fetal/metabolismo , Galectina 1/imunologia , Células Matadoras Naturais/metabolismo , Linfócitos T Reguladores/metabolismo , Adulto , Antígenos CD/genética , Antígenos CD/imunologia , Linfócitos T CD8-Positivos/efeitos dos fármacos , Linfócitos T CD8-Positivos/imunologia , Proliferação de Células/efeitos dos fármacos , Células Cultivadas , Feminino , Sangue Fetal/efeitos dos fármacos , Sangue Fetal/imunologia , Citometria de Fluxo , Galectina 1/genética , Galectina 1/farmacologia , Regulação da Expressão Gênica no Desenvolvimento/imunologia , Humanos , Memória Imunológica , Células Matadoras Naturais/efeitos dos fármacos , Células Matadoras Naturais/imunologia , Contagem de Linfócitos , Masculino , Linfócitos T Reguladores/efeitos dos fármacos , Linfócitos T Reguladores/imunologiaRESUMO
PROBLEM: Calcium handling of T lymphocytes is altered in healthy pregnancy (HP) and preeclampsia (PE) compared to non-pregnant (non-P) women. We compared the activation-elicited calcium influx in T lymphocytes in HP, PE and non-P women and tested its alteration upon inhibition of Kv1.3 and IKCa1 potassium channels. METHOD OF STUDY: The alteration of calcium influx was measured in major T-lymphocyte subsets of 9 non-P, HP and PE women with flow cytometry with or without treatment of cells with potassium channel inhibitors. RESULTS: The elicited calcium response was lower in HP compared to non-P. In HP, calcium influx was sensitive to potassium channel inhibition in CD8 and Th1, but not in Th2 cells. In PE, calcium influx and its sensitivity to inhibition were comparable to non-P. CONCLUSION: There is a characteristic pattern of calcium influx in T lymphocytes and its sensitivity to potassium channel inhibition in HP that is missing in PE, raising the notion that T-lymphocyte calcium handling may have a role in the characteristic immune status of HP.
