Immunogenicity of ChAd63 + MVA ME-TRAP in Senegalese adults

Victorine Mensah,Badara Cisse,Babacar Faye,Katie Ewer,Danny Wright,Nicola Viebig,Adrian Hill,Magatte Ndiaye,Nick Edwards,Phillip Bejon

doi:10.1186/1475-2875-13-s1-p93

Abstract

Background While malaria transmission is falling in many areas due to increased use of bed-nets and anti-malarials, it remains an enormous burden [1]. The leading malaria vaccine candidate, RTS,S, results in often considerably less than 60% efficacy against clinical malaria [2] resulting in a need for other approaches that may enhance this partial protection. One such approach is the use of viral vectors in a heterologous prime-boost regime with the aim of inducing a T-cell response. Previous studies have shown high levels of immunogenicity by using a chimpanzee adenovirus (ChAd63) followed by an attenuated vaccinia virus (modified vaccinia Ankara (MVA)) to deliver the pre-erythrocytic antigen, multiple epitope string with thrombospondin-related adhesion protein (ME-TRAP) [3].

Highlights

While malaria transmission is falling in many areas due to increased use of bed-nets and anti-malarials, it remains an enormous burden [1]
Volunteers received either ChAd63 followed by MVA, both containing multiple epitope string with thrombospondin-related adhesion protein (ME-TRAP), or two shots of rabies vaccine
Intracellular cytokine staining was used to determine the relative proportions of CD4+ and CD8+ T-cells secreting IL-2, IFN-g and/or TNFa in response to peptide stimulation

Summary

Introduction

While malaria transmission is falling in many areas due to increased use of bed-nets and anti-malarials, it remains an enormous burden [1]. Materials and methods We undertook a phase IIb study to assess the efficacy and further evaluate the immunogenicity and safety of such a vaccination strategy involving 120 healthy adults in Dakar, Senegal.

Results

Conclusion