Synthetic adjuvants to potentiate the immune response against rAg85B by nasal route.

Respiratory infections continue to pose a significant global health challenge due to the rapid mutation of pathogens and the re-emergence of drug-resistant bacterial infections. To address these concerns, researchers have explored the development of nasal vaccines capable of inducing a robust immune response both at the respiratory tract and systemic levels.

Two synthetic compounds, ODN-39M and peptide LALF32-51, were selected as potential nasal vaccine adjuvants for the Ag85B antigen derived from Mycobacterium tuberculosis.

In this study, the investigational adjuvants were subjected to evaluation in Balb/C mice following intranasal immunization. The findings revealed that ODN-39M effectively enhanced the immune response, primarily promoting a Th1 pattern. This particular vaccine preparation, comprising ODN-39M combined with Ag85B, demonstrated potent cell-mediated and high IgA specific antibody responses in the lungs, alongside systemic immunity.

To further understand the interaction between ODN-39M and NALT immune cells, a preliminary study was conducted. The results indicated early lymphoid cell recruitment and an increase in CD69 activation marker, predominantly observed in B and dendritic cells. While additional research is necessary to fully comprehend the functioning of NALT, including the development of local innate response, these findings contribute valuable insights to the limited existing knowledge on this compartment.

The current data support the utilization of ODN-39M as a potent and potentially safe adjuvant option for the development of future nasal vaccines targeting respiratory infections, such as tuberculosis.