RESUMEN
In this study, we report the purification and characterization of a multifunctional lectin (MvFL) from Microgramma vacciniifolia fronds as well as its immunomodulatory properties on human peripheral blood mononuclear cells (PBMCs). MvFL (pI 4.51; 54kDa) is a glycoprotein able to inhibit trypsin activity and that has sequence similarities (32% coverage) with a plant RNA-binding protein. Hemagglutinating activity of MvFL was not altered by heating at 100°C for 30min, but was reduced in alkaline pH (8.0 and 9.0). Fluorimetric analyses showed that this lectin did not undergo marked conformational changes when heated. However, the MvFL conformation changed depending on the pH. MvFL at 6.25-25µg/mL was not cytotoxic to lymphocytes present among PBMCs. The PBMCs incubated for 24h with the lectin (12.5µg/mL) showed increased TNF-α, IFN-γ, IL-6, IL-10, and nitric oxide production. MvFL also stimulated T lymphocytes from PBMCs to differentiate into CD8+ cells. The activation (indicated by CD28 expression) of these cells was also stimulated. In conclusion, MvFL is a heat-stable and multifunctional protein, with both lectin and trypsin inhibitor activities, and capable of inducing predominantly a Th1 response in human PBMCs as well as activation and differentiation of T lymphocytes.
Asunto(s)
Factores Inmunológicos/farmacología , Lectinas de Plantas/farmacología , Polypodiaceae/química , Supervivencia Celular/efectos de los fármacos , Humanos , Leucocitos Mononucleares/citología , Leucocitos Mononucleares/efectos de los fármacos , Leucocitos Mononucleares/inmunologíaRESUMEN
Tuberculosis is the most prevalent infectious disease in the world. Granuloma formation and caseous necrosis are hallmarks of M. tuberculosis infection and they represent the protective and inflammatory reactions in the infected tissues. The molecular mechanisms that mediate granuloma necrosis are still not well understood. Objectives: To immunolocalize and correlate the amounts of CD68+ macrophages and CD8+ lymphocytes to caseous necrosis extension in granulomas of tuberculous pleurisy. Methods: The study is a retrospective analysis of 30 pleural biopsies with histopathological diagnosis of chronic granulomatous pleurisy with caseous necrosis. These biopsies were classified according to necrosis intensity as minimal (N1), moderate (N2) and intense (N3). The number of granulomas was also observed and categorized as G1 (1 to 4 granulomas per section), G2 (5 to 8 granulomas per section), and G3 (more than 8 granulomas per section). Results: The means of CD68+ cells counts per mm² in N1, N2 and N3 categories of necrosis were 1,287 +/- 254, 1086 +/- 181 and 930 +/- 115 respectively. The means for CD8+ cells were 483.7 +/- 396, 366.3 +/- 43 and 558 +/- 53 cells per mm² in N1, N2 and N3 respectively. Conclusions: There were no significant statistical correlations between necrosis extension and cell counts. In analyzed biopsies, the number of CD68+ cells was significantly higher than the number of CD8+ cells.
La tuberculosis es una de las enfermedades más prevalentes en el mundo. La formación del granuloma junto con la necrosis caseosa son características propias de la infección por M. tuberculosis y representan reacciones inflamatorias y protectoras en los tejidos infectados. No se conocen bien los mecanismos moleculares que median la necrosis en el granuloma. Los objetivos fueron inmunolocalizar y correlacionar la cantidad de macrófagos CD68+ y linfocitos CD8+ con la extensión de la necrosis caseosa, en los granulomas de tuberculosis pleural. Análisis retrospectivo que incluyeron 30 biópsias con diagnóstico histopatológico de tuberculosis pleural granulomatosa crónica con necrosis caseosa. Estas biópsias fueron clasificadas según la intensidad de necrosis como mínima (N1), moderada (N2) e intensa (N3). También se determinó el número de granulomas, que fueron clasificados como G1 (1 a4 granulomas por sección), G2 (5 a 8 granulomas por sección), y G3 (más de 8 granulomas por sección). La cuantificación de células CD68+ por mm² en las categorías N1, N2 y N3 de necrosis fue de 1,287 +/- 254; 1086 +/-181 y 930 +/- 115, respectivamente. La cuantificación de las células CD68+ fue de 483,7 +/- 396; 366,3 +/- 43 y 558 +/- 53 células por mm² para N1, N2 y N3, respectivamente. No hubo correlación estadísticamente significativa entre la extensión de la necrosis y la cuantificación celular. El número de células CD68+ fue significativamente mayor que el número de células CD8+ en las biópsias analizadas.