INVESTIGATION OF IL-6 EFFECTS ON SP-A EXPRESSION IN A549 LUNG CELL LINE

Interleukin-6 (IL-6) is a multifunctional cytokine that is important in inflammatory processes, cell differentiation and growth. Pulmonary surfactant is a protein-lipid complex, which reduce surface tension at the alveolar air-liquid interface, thereby preventing lung collapse. Surfactant protein A (SP-A) is the most abundant of four surfactant proteins (SP-A, SP-B, SP-C and SP-D). It binds to alveolar macrophages, stimulates their chemotaxis and serves as an opsonin in the phagocytosis. Low SP-A levels are associated with increased inflammation in the lung. In the absence of infection SP-A inhibited IL-6 production. In infected macrophages, SP-A augmented IL-6 production. In humans, SP-A levels are altered by a number of disease states. In some of them there is increased levels of SP-A in the bronchoalveolar lavage fluid. Here we investigate presence/absence of correlation between increased levels of IL-6 and production of SP-A from A549 lung cell line. Our results suggest that incubation of A549 cells with IL-6 for different time changes significantly the expression levels of SP-A.