Back to Search Start Over

Chemically Synthesized Alcaligenes Lipid A as an Adjuvant to Augment Immune Responses to Haemophilus Influenzae Type B Conjugate Vaccine

Authors :
Zilai Liu
Koji Hosomi
Atsushi Shimoyama
Ken Yoshii
Xiao Sun
Huangwenxian Lan
Yunru Wang
Haruki Yamaura
Davie Kenneth
Azusa Saika
Takahiro Nagatake
Hiroshi Kiyono
Koichi Fukase
Jun Kunisawa
Source :
Frontiers in Pharmacology, Vol 12 (2021)
Publication Year :
2021
Publisher :
Frontiers Media SA, 2021.

Abstract

We previously identified Alcaligenes spp. as a commensal bacterium that resides in lymphoid tissues, including Peyer’s patches. We found that Alcaligenes-derived lipopolysaccharide acted as a weak agonist of Toll-like receptor four due to the unique structure of lipid A, which lies in the core of lipopolysaccharide. This feature allowed the use of chemically synthesized Alcaligenes lipid A as a safe synthetic vaccine adjuvant that induces Th17 polarization to enhance systemic IgG and respiratory IgA responses to T-cell–dependent antigens (e.g., ovalbumin and pneumococcal surface protein A) without excessive inflammation. Here, we examined the adjuvant activity of Alcaligenes lipid A on a Haemophilus influenzae B conjugate vaccine that contains capsular polysaccharide polyribosyl ribitol phosphate (PRP), a T-cell–independent antigen, conjugated with the T-cell–dependent tetanus toxoid (TT) antigen (i.e., PRP-TT). When mice were subcutaneously immunized with PRP alone or mixed with TT, Alcaligenes lipid A did not affect PRP-specific IgG production. In contrast, PRP-specific serum IgG responses were enhanced when mice were immunized with PRP-TT, but these responses were impaired in similarly immunized T-cell—deficient nude mice. Furthermore, TT-specific—but not PRP-specific—T-cell activation occurred in mice immunized with PRP-TT together with Alcaligenes lipid A. In addition, coculture with Alcaligenes lipid A promoted significant proliferation of and enhanced antibody production by B cells. Together, these findings suggest that Alcaligenes lipid A exerts an adjuvant activity on thymus-independent Hib polysaccharide antigen in the presence of a T-cell–dependent conjugate carrier antigen.

Details

ISSN :
16639812
Volume :
12
Database :
OpenAIRE
Journal :
Frontiers in Pharmacology
Accession number :
edsair.doi.dedup.....af6a691792ec65609444aa795f576274