Vaccination with a Fusion Protein That Introduces HIV-1 Gag Antigen into a Multitrimer CD40L Construct Results in Enhanced CD8 ⁺ T Cell Responses and Protection from Viral Challenge by Vaccinia-Gag

Abstract

b CD40 ligand (CD40L, CD154) is a membrane protein that is important for the activation of dendritic cells (DCs) and DC-induced CD8؉ T cell responses. To be active, CD40L must cluster CD40 receptors on responding cells. To produce a soluble form of CD40L that clusters CD40 receptors necessitates the use of a multitrimer construct. With this in mind, a tripartite fusion protein was made from surfactant protein D (SPD), HIV-1 Gag as a test antigen, and CD40L, where SPD serves as a scaffold for the multitrimer protein complex. This SPD-Gag-CD40L protein activated CD40-bearing cells and bone marrow-derived DCs in vitro. Compared to a plasmid for Gag antigen alone (pGag), DNA vaccination of mice with pSPD-Gag-CD40L induced an increased number of Gag-specific CD8 ؉ T cells with increased avidity for major histocompatibility complex class I-restricted Gag peptide and improved vaccine-induced protection from challenge by vaccinia-Gag virus. The importance of the multitrimeric nature of the complex was shown using a plasmid lacking the N terminus of SPD that produced a single trimer fusion protein. This plasmid, pTrimer-Gag-CD40L, was only weakly active on CD40-bearing cells and did not elicit strong CD8؉ T cell responses or improve protection from vaccinia-Gag challenge. An adenovirus 5 (Ad5) vaccine incorporating SPD-Gag-CD40L was much stronger than Ad5 expressing Gag alone (Ad5-Gag) and induced complete protection (i.e., sterilizing immunity) from vaccinia-Gag challenge. Overall, these results show the potential of a new vaccine design in which antigen is introduced into a construct that expresses a multitrimer soluble form of CD40L, leading to strongly protective CD8 ؉ T cell responses.

Constitutively Active MAVS Inhibits HIV-1 Replication via Type I Interferon Secretion and Induction of HIV-1 Restriction Factors

“…To confirm biological activity of Ad5-ΔLMP1-MAVS, we evaluated NF-κB mediated signaling in the presence or absence of doxycycline. An HEK-293 cell line expressing secreted alkaline phosphatase under the control of NF-κB [ 50 ] was transfected with Ad5-GFP control or Ad5-ΔLMP1-MAVS in the presence or absence of doxycycline. As shown in Fig 7A , in the presence of doxycycline, Ad5-ΔLMP1-MAVS transduced cells secreted significantly higher levels of SEAP compared to Ad5-ΔLMP1-MAVS transduced cells in the absence of doxycycline or control cells.…”

Anti-CD40 Antibody Fused to CD40 Ligand Is a Superagonist Platform for Adjuvant Intrinsic DC-Targeting Vaccines

“…The observed in vitro increases in efficacy and potency for eliciting, respectively, antigen-specific CD8 + and CD4 + T cell responses raise the possibility that anti-CD40-CD40L-based antigen fusions may have advantages when used in vivo. In particular, the high agonist activity of this novel vaccine format offers promise of efficacious immune responses when used without The concept of vaccination via co-administrating activation of CD40 concomitantly with antigen delivery has also been approached using multimeric forms of CD40L fused to antigen, and in vivo mouse studies have shown promising efficacy for antibody (36,37) and protective T cell responses (38)(39)(40).…”

Enhanced anti-tumor therapeutic efficacy of DNA vaccine by fusing the E7 gene to BAFF in treating human papillomavirus-associated cancer

“…Fas, CD40, and OX40L) [ 6 ]. Fusion of HIV Gag protein with CD40L was demonstrated to enhance DC maturation in mouse model and induced CD8 + T cell response [ 29 ]. In this study, however, BAFF-E7 chimerical DNA vaccine did not alter the maturation pattern of DC.…”