# An Adjuvanted Vaccine-Induced Pathogenesis Following Influenza Virus Infection

## TL;DR

This study shows that certain vaccine adjuvants can cause harmful immune responses in mice after influenza infection.

## Contribution

The research identifies how specific adjuvants can either enhance immunity or cause pathogenesis, highlighting the need for precision adjuvants.

## Key findings

- Incomplete Freund’s adjuvant caused severe pathogenesis despite high antibody levels.
- Aluminum hydroxide adjuvant alone provided complete protection against influenza mortality and morbidity.
- C34, a glycolipid analogue, reduced the stimulatory effect of aluminum hydroxide adjuvant.

## Abstract

An incomplete Freund’s adjuvant elicited an overt pathogenesis in vaccinated mice following the intranasal challenge of A/California/07/2009 (H1N1) virus despite the induction of a higher specific antibody titer than other adjuvanted formulations. Aluminum hydroxide adjuvants have not induced any pathogenic signs in a variety of formulations with glycolipids. A glycolipid, α-galactosyl ceramide, improved a stimulatory effect of distinct adjuvanted formulations on an anti-influenza A antibody response. In contrast to α-galactosyl ceramide, its synthetic analogue C34 was antagonistic toward a stimulatory effect of an aluminum hydroxide adjuvant on a specific antibody response. The aluminum hydroxide adjuvant alone could confer complete vaccine-induced protection against mortality as well as morbidity caused by a lethal challenge of the same strain of an influenza A virus. The research results indicated that adjuvants could reshape immune responses either to improve vaccine-induced immunity or to provoke an unexpected pathogenic consequence. On the basis of these observations, this research connotes the prominence to develop a precision adjuvant for innocuous vaccination aimed at generating a protective immunity without aberrant responses.