Adjuvant activity of polar glycopeptidolipids of Mycobacterium chelonae (pGPL-Mc) on the immunogenic and protective effects of an inactivated influenza vaccine.

Mice injected intraperitoneally with 2.5 or 25 mg/kg of pGPL-Mc, before, during or after the administration of a monovalent inactivated influenza vaccine (8 IU of A/New Jersey/X53), exhibited significantly very high haemagglutination inhibition (HI) antibody titers (up to 8 fold) as compared to vaccine controls. Treatment with pGPL-Mc has increased the protective effect of the vaccine by completely abolishing, in certain treatment groups, the onset of symptoms of disease and mortality after a lethal challenge with 5 LD50 of A/PR/8/34 virus, 60 days after the first vaccination. Moreover, the development of visible pulmonary lesions significantly decreased in surviving vaccinated mice treated with 25 mg/kg of pGPL-Mc on day D0. These results suggest that pGPL-Mc is a potent adjuvant to the immunogenic and protective effect of inactivated influenza vaccines.