RESUMEN
The immunomodulatory functions mediated by melatonin support its use as vaccine adjuvant. Previously, we have demonstrated that melatonin enhances antibody responses in sheep vaccinated against Dichelobacter nodosus. Here, we analyze the effect of melatonin on T and B lymphocyte subsets in peripheral blood of sheep vaccinated against D. nodosus. We also compare the use of melatonin in implants and in injections. Melatonin administration either as implants or by injection produced higher antibody titers against A1 and C serotypes compared to those animals that received only the vaccine. These results support the use of melatonin as an adjuvant in vaccination against D. nodosus. Firstly, melatonin induces higher antibody titer than the vaccine alone, secondly, melatonin increase IgG+ B lymphocytes and CD4+ T lymphocytes in vaccinated sheep. These results suggest that melatonin enhances T CD4 cell activation and subsequently secondary humoral immune responses. Further studies are required to determine the mechanism underlining the immunomodulatory role of melatonin in the context of vaccination.
Asunto(s)
Linfocitos B/inmunología , Vacunas Bacterianas/inmunología , Linfocitos T CD4-Positivos/inmunología , Dichelobacter nodosus/inmunología , Infecciones por Bacterias Gramnegativas/veterinaria , Melatonina/uso terapéutico , Enfermedades de las Ovejas/inmunología , Adyuvantes Inmunológicos/uso terapéutico , Administración Cutánea , Animales , Anticuerpos Antibacterianos/sangre , Vacunas Bacterianas/administración & dosificación , Implantes de Medicamentos , Femenino , Citometría de Flujo/veterinaria , Infecciones por Bacterias Gramnegativas/inmunología , Infecciones por Bacterias Gramnegativas/prevención & control , Inmunogenicidad Vacunal/efectos de los fármacos , Inmunoglobulina G/sangre , Melatonina/administración & dosificación , Distribución Aleatoria , Ovinos , Enfermedades de las Ovejas/prevención & controlRESUMEN
Melatonin has been shown to exert immunomodulatory properties with broad application in veterinary medicine. Here we have investigated the effect of exogenous melatonin in the improvement of the immune response to administration of an immune-preparation of two stumps of A1 and C strains of Dichelobacter nodosus in sheep. Subcutaneous administration of melatonin enhanced plasma levels of melatonin from days 42 to 120. Administration of melatonin to vaccinated animals enhanced both the titer of antibodies and serum IgG levels to A1 and C strains of D. nodosus compared to vaccinated animals not treated with melatonin. Our results suggest that melatonin increased the immune response to vaccination and open new perspectives in the design of prophylactic strategies.