Impact of the GK-1 adjuvant on peritoneal macrophages gene expression and phagocytosis

Purpose: The synthetic peptide GK-1 potentiates protective immunity elicited by the influenza vaccine in mice. In order to understand its adjuvant properties, this study was designed to determine the impact of GK-1 on gene expression and phagocytosis of peritoneal macrophages (PMa). Methods: Increased gene expression of chemokines involved in leukocyte recruitment and of pro-inflammatory mediators was detected by microarray analysis of control and GK-1 treated PMa macrophages. The expression profile was subsequently confirmed by Multiplex Immunoassays analysis to measure cytokines levels, flow cytometer to describe M1/M2 surface markers and an assay to evaluate their phagocytic activity. Results: Treatment of PMa with GK-1 results in development to the classically activated M1 functional macrophage subpopulation with increased expression of the CCL3 and CXCLO2 chemokines, IL-6 and TNF-alpha proinflammatory cytokines with a concomitant increase in the levels of NO, accompanied by the expression of modulatory factors that downregulate the inflammatory phenotype. GK-1 treated PMa significantly increased their phagocytic activity. Conclusion: GK-1 classical activated with enhanced phagocitic capacity may underlie in the increased specific immunity induced when concomitant administered with other antigens.