A TLR4-derived non-cytotoxic, self-assembling peptide functions as a vaccine adjuvant in mice

Abstract

Vaccination is devised/formulated to stimulate specific and prolonged immune responses for long-term protection against infection or disease. A vaccine component, namely adjuvant, enhances antigen recognition by the host immune system and thereby stimulates its cellular and adaptive responses. Especially synthetic Toll-like receptor (TLR) agonists having selfassembling properties are considered as good candidates for adjuvant development. Here, a human TLR4-derived 20-residue peptide (TR-433), present in the dimerization interface of the TLR4 -myeloid differentiation protein-2 (MD2) complex, displayed self-assembly and adopted a nanostructure. Both in vitro studies and in vivo experiments in mice indicated that TR-433 is nontoxic. TR-433 induced pro-inflammatory responses in THP-1 monocytes and HEK293T cells that were transiently transfected with TLR4/CD14/MD2 and also in BALB/c mice. In light of the self-assembly and pro-inflammatory properties of TR-433, we immunized with a mixture of TR-433 and either ovalbumin or filarial antigen trehalose-6-phosphate phosphatase (TPP). A significant amount of IgG titers was produced, suggesting adjuvanting capability of TR-433 that was comparable with that of Freund's complete adjuvant (FCA) and appreciably higher than that of alum. We found that TR-433 preferentially activates type 1 helper T cell (T h 1) response rather than type 2 helper T cell (T h 2) response. To our knowledge, this is the first report on the identification of a short TLR4-derived peptide that possesses both self-assembling and pro-inflammatory properties and has significant efficacy as an adjuvant, capable of activating cellular responses in mice. These results indicate that TR-433 possesses significant potential for development as a new adjuvant in therapeutic application. 2 The abbreviations used are: FCA, Freund's complete adjuvant; FIA, Freund's incomplete adjuvant; TLR, Toll-like receptor; LPS, lipopolysaccharide; TPP, trehalose-6-phosphate phosphatase; MTT, 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide; TEM, transmission EM; ThT, thioflavin T; TNF, tumor necrosis factor; IL, interleukin; PMA, phorbol 12-myristate 13-acetate; Ova, ovalbumin; HRP, horseradish peroxidase; IFN, interferon. Figure 8. TR-433 adjuvant activity depends on T-bet expression. mRNA expressions of T-bet and GATA-3 were analyzed in splenocytes in duplicates in two independent experiments (n ϭ 2). Mouse glyceraldehyde-3-phosphate dehydrogenase was used as an endogenous control, and relative -fold change was determined by the comparative ⌬CT method. Statistical analysis was carried out using one-way analysis of variance using Dunnett's test.

A cutting-edge immunoinformatics approach for design of multi-epitope oral vaccine against dreadful human malaria

“…These clearly indicated that the PVs without adjuvants have interacting domain to induce innate immune system. This is in agreement with the recent study where human TLR4-derived self-assembling peptide nanoparticles have been used as non toxic vaccine adjuvant with filarial antigenic protein to induce the immunological responses in mice [103].…”

In silicodesign of Multi-epitope-based peptide vaccine against SARS-CoV-2 using its spike protein

“…agonists [78][79][80][81][82][83][84] was designed and validated to have overlapping B cell epitope regions through the IEDB server. The adjuvant sequences have been experimentally evidenced to generate neutralizing antibodies, cytokines and natural killer cells.…”

“…The triagonist chimeric adjuvant has the propensity to elicit immune responses to allow for its use as a suitable adjuvant against SARS CoV 2. RS09 [78], TR-433 [79] and a Mtb based Hsp70 partial sequence [80,81] were utilized in this endeavor. An appropriate rigid polar linker (DP) was utilized in this regard.…”

In silico design of multi-epitope-based peptide vaccine against SARS-CoV-2 using its spike protein

“…The triagonist chimeric adjuvant has the propensity to elicit immune responses to allow for its use as a suitable adjuvant against SARS-CoV-2. RS09 (Shanmugam et al, 2012), TR-433 (Tandon et al, 2018), and an MTB based Hsp70 partial sequence (Dabaghian et al, 2015;Reed et al, 2016) were utilized in this endeavor. An appropriate rigid polar linker (DP) was utilized in this regard.…”