Safety and immunogenicity of placental malaria vaccine PRIMVAC in adults in Europe and Burkina Faso (PRIMALVAC)

Objectives

The primary objective of the study is to evaluate the safety of 3 different dosages (20µg – 50µg and 100µg) of a placental malaria vaccine candidate (PRIMVAC vaccine) adjuvanted either with Alhydrogel® or GLA-SE, and administered at D0, D28 and D56 in healthy European and Burkinabe adults.

Secondary objectives are to assess:

1. The humoral immune response to the PRIMVAC vaccine antigen (VAR2CSA) by measuring the variation in the level of total IgG and the level of the isotypic subtypes capable of recognizing the native antigen.
2. The cellular immune response by measuring:
   1. The number of T cells secreting IL5 and IFNg following an ex-vivo stimulation with the vaccine antigen
   2. The B lymphocyte phenotypes isolated from PBMC

Exploratory objectives are:

1. To explore the quality of the humoral immune response by the measure of the capability of the antibodies specific to the vaccine antigen to:
   1. Cross-react with different VAR2CSA variants expressed on the surface of erythrocytes infected by various strains of Plasmodium falciparum,
   2. Inhibit interactions between parasitized erythrocytes expressing different VAR2CSA variants and Chondroitin Sulfate A (receptor involved in placental sequestration),
   3. Promote opsonic phagocytosis of parasitized erythrocytes with various strains of Plasmodium falciparum expressing different VAR2CSA variants
2. To explore the quality of the cellular immune response induced by the vaccine antigen by the quantitation of a large panel of cytokines in the ELISpot supernatants.