β-Glycoglycosphingolipid-induced augmentation of the anti-HBV immune response is associated with altered CD8 and NKT lymphocyte distribution: A novel adjuvant for HBV vaccination

SummaryBackground: Non-responsiveness towards the currently used hepatitis B virus (HBV) vaccine is a major problem in attempts to protect against HBV infection. Several methods have been tested to overcome the lack of an effective immune response towards HBV antigens. Adjuvants that augment the immunologic reaction are essential components of the vaccines. β-Glycosphingolipids exert a natural killer T cell (NKT)-mediated immunomodulatory effect in various disorders. Aims: The aim of the present study was to test the ability of these compounds to augment the immune response towards HBV antigens, making them potential adjuvants for HBV vaccines. Six groups of mice were injected with different formulations of an HBV vaccine, along with various doses of β-glucosylceramide (β-GC), β-lactosylceramide (β-LC), or a combination of both (IGL) in different doses. The effect of β-glycosphingolipids on the immune response towards HBV was tested by fluorescence-activated cell sorting analysis of hepatic and splenic NKT and CD8 lymphocytes, and serum cytokine levels. Results: β-Sphingolipid treatment altered the hepatic NKT and CD8 lymphocyte distribution. β-LC, β-GC, and the combination of both augmented anti-HBV immunity, increasing both the anti-HBs titers and the percentage of mice exhibiting high titers. This effect was associated with altered hepatic NKT and CD8+ lymphocyte distribution. Conclusions: In summary, β-glycosphingolipids increased the anti-HBV immune response in association with an altered NKT and CD8 lymphocyte distribution, making β-glycosphingolipids potential potent adjuvants for overcoming non-responsiveness to HBV vaccination and augmenting the anti-viral immune response.