title: Llama immunization with full-length VAR2CSA generates cross-reactive and inhibitory single-domain antibodies against the DBL1X domain.
abstract: VAR2CSA stands today as the leading vaccine candidate aiming to protect future pregnant women living in malaria endemic areas against the severe clinical outcomes of pregnancy associated malaria (PAM). The rational design of an efficient VAR2CSA-based vaccine relies on a profound understanding of the molecular interactions associated with P. falciparum infected erythrocyte sequestration in the placenta. Following immunization of a llama with the full-length VAR2CSA recombinant protein, we have expressed and characterized a panel of 19 nanobodies able to recognize the recombinant VAR2CSA as well as the surface of erythrocytes infected with parasites originating from different parts of the world. Domain mapping revealed that a large majority of nanobodies targeted DBL1X whereas a few of them were directed towards DBL4ε, DBL5ε and DBL6ε. One nanobody targeting the DBL1X was able to recognize the native VAR2CSA protein of the three parasite lines tested. Furthermore, four nanobodies targeting DBL1X reproducibly inhibited CSA adhesion of erythrocytes infected with the homologous NF54-CSA parasite strain, providing evidences that DBL1X domain is part or close to the CSA binding site. These nanobodies could serve as useful tools to identify conserved epitopes shared between different variants and to characterize the interactions between VAR2CSA and CSA.
authors.affiliation: 1] Inserm UMR_1134, Paris, France [2] Université Paris Diderot, Sorbonne Paris Cité, UMR_S1134 Paris, France [3] Institut National de la Transfusion Sanguine, Paris, France [4] Laboratory of excellence GR-Ex, Paris, France.
authors.forename: Sofia
authors.initials: S
authors.lastname: Nunes-Silva
authors.affiliation: 1] Inserm UMR_1134, Paris, France [2] Université Paris Diderot, Sorbonne Paris Cité, UMR_S1134 Paris, France [3] Institut National de la Transfusion Sanguine, Paris, France [4] Laboratory of excellence GR-Ex, Paris, France.
authors.forename: Stéphane
authors.initials: S
authors.lastname: Gangnard
authors.affiliation: 1] Inserm UMR_1134, Paris, France [2] Université Paris Diderot, Sorbonne Paris Cité, UMR_S1134 Paris, France [3] Institut National de la Transfusion Sanguine, Paris, France [4] Laboratory of excellence GR-Ex, Paris, France.
authors.forename: Marta
authors.initials: M
authors.lastname: Vidal
authors.affiliation: 1] VIB, Structural Biology Research Center, Brussels, Belgium [2] Structural Biology Brussels, Vrije Universiteit Brussel, Belgium.
authors.forename: Anneleen
authors.initials: A
authors.lastname: Vuchelen
authors.affiliation: 1] Inserm UMR_1134, Paris, France [2] Université Paris Diderot, Sorbonne Paris Cité, UMR_S1134 Paris, France [3] Institut National de la Transfusion Sanguine, Paris, France [4] Laboratory of excellence GR-Ex, Paris, France.
authors.forename: Sebastien
authors.initials: S
authors.lastname: Dechavanne
authors.affiliation: Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, Stockholm, Sweden.
authors.forename: Sherwin
authors.initials: S
authors.lastname: Chan
authors.affiliation: 1] VIB, Structural Biology Research Center, Brussels, Belgium [2] Structural Biology Brussels, Vrije Universiteit Brussel, Belgium.
authors.forename: Els
authors.initials: E
authors.lastname: Pardon
authors.affiliation: 1] VIB, Structural Biology Research Center, Brussels, Belgium [2] Structural Biology Brussels, Vrije Universiteit Brussel, Belgium.
authors.forename: Jan
authors.initials: J
authors.lastname: Steyaert
authors.affiliation: 1] VIB, Structural Biology Research Center, Brussels, Belgium [2] Structural Biology Brussels, Vrije Universiteit Brussel, Belgium.
authors.forename: Stephanie
authors.initials: S
authors.lastname: Ramboarina
authors.affiliation: 1] Inserm UMR_1134, Paris, France [2] Université Paris Diderot, Sorbonne Paris Cité, UMR_S1134 Paris, France [3] Institut National de la Transfusion Sanguine, Paris, France [4] Laboratory of excellence GR-Ex, Paris, France.
authors.forename: Arnaud
authors.initials: A
authors.lastname: Chêne
authors.affiliation: 1] Inserm UMR_1134, Paris, France [2] Université Paris Diderot, Sorbonne Paris Cité, UMR_S1134 Paris, France [3] Institut National de la Transfusion Sanguine, Paris, France [4] Laboratory of excellence GR-Ex, Paris, France.
authors.forename: Benoît
authors.initials: B
authors.lastname: Gamain
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D000953:Antigens, Protozoan / Q000737:chemistry / Q000276:immunology*; D002161:Camelids, New World; D003429:Cross Reactions / Q000276:immunology*; D018604:Epitope Mapping; D000939:Epitopes / Q000737:chemistry / Q000276:immunology; D004912:Erythrocytes / Q000469:parasitology; D005260:Female; D006801:Humans; D007114:Immunization; D007700:Kinetics; D008969:Molecular Sequence Data; D010920:Placenta; D011247:Pregnancy; D011485:Protein Binding; D011487:Protein Conformation; D054730:Protein Interaction Domains and Motifs / Q000276:immunology*; D011994:Recombinant Proteins / Q000737:chemistry / Q000276:immunology; D016415:Sequence Alignment; D061905:Single-Domain Antibodies / Q000276:immunology*
chemical_list: D000953:Antigens, Protozoan; D000939:Epitopes; D011994:Recombinant Proteins; D061905:Single-Domain Antibodies; C512601:VAR2CSA protein, Plasmodium falciparum