A Combined Adjuvant TF-Al Consisting of TFPR1 and Aluminum Hydroxide Augments Strong Humoral and Cellular Immune Responses in Both C57BL/6 and BALB/c Mice.

Qiao Li,Jiayi Shu,Zhihua Kou,Zhihua Liu,Yi Liu,Chuanyou Li,Chen Liang,Xia Jin

doi:10.3390/vaccines9121408

Abstract

TFPR1 is a novel adjuvant for protein and peptide antigens, which has been demonstrated in BALB/c mice in our previous studies; however, its adjuvanticity in mice with different genetic backgrounds remains unknown, and its adjuvanticity needs to be improved to fit the requirements for various vaccines. In this study, we first compared the adjuvanticity of TFPR1 in two commonly used inbred mouse strains, BALB/c and C57BL/6 mice, in vitro and in vivo, and demonstrated that TFPR1 activated TLR2 to exert its immune activity in vivo. Next, to prove the feasibility of TFPR1 acting as a major component of combined adjuvants, we prepared a combined adjuvant, TF–Al, by formulating TFPR1 and alum at a certain ratio and compared its adjuvanticity with that of TFPR1 and alum alone using OVA and recombinant HBsAg as model antigens in both BALB/c and C57BL/6 mice. Results showed that TFPR1 acts as an effective vaccine adjuvant in both BALB/c mice and C57BL/6 mice, and further demonstrated the role of TLR2 in the adjuvanticity of TFPR1 in vivo. In addition, we obtained a novel combined adjuvant, TF–Al, based on TFPR1, which can augment antibody and cellular immune responses in mice with different genetic backgrounds, suggesting its promise for vaccine development in the future.

Highlights

Adjuvants are formulated as an important component of vaccines that aim to enhance immune responses and/or change the type of immune responses [1,2,3,4]
Alum induced a Th2-biased antibody responses (Figure 1C) and greater amounts of IL-4 (Figure 1E). These results showed that TFPR1 has similar adjuvanticity for OVA in C57BL/6 mice and BALB/c mice [31], though it induces higher levels of cellular immune responses
Unlike Pam3CSK4, TFPR1 still stimulated TLR2KO mice to secret most cytokines except IL-6 (Figure 3B) but with significantly lower levels (IFN-γ, IL-8, and IL-10). These results further proved that TFPR1 acts as an efficient adjuvant by activating immune cells primarily, but partially through toll-like receptor 2 (TLR2)

Summary

Introduction

Adjuvants are formulated as an important component of vaccines that aim to enhance immune responses and/or change the type of immune responses [1,2,3,4]. BALB/c mice and C57BL/6 mice are the most commonly used inbred mouse strains in the laboratory, because they are homozygous and genetically stable and have clear background information [23,24]. There are several differences between the two kinds of mouse strains in immunology and when it comes to applications. They have different gene sequences at the H2 site of the classImajor histocompatibility complex (MHC) gene locus: C57BL/6 mice is H2b but BALB/c mice is H2d. Macrophages, DCs and NK cells from C57BL/6 mice produced higher levels of TNF-α, IL-12 and IFN-γ than those from BALB/c mice after exogenous stimulation, which may affect the development of Th1 and Th2 adaptive immunity [25,26,27]. The adjuvanticity of TFPR1 in mice with different genetic backgrounds remains unknown, and its adjuvanticity needs to be improved to fit the requirements for various vaccines

Methods

Results

Conclusion