New malaria vaccine candidates based on the Plasmodium vivax Merozoite Surface Protein-1 and the TLR-5 agonist Salmonella Typhimurium FliC flagellin.
The present study evaluated the immunogenicity of new malaria vaccine formulations based on the 19kDa C-terminal fragment of Plasmodium vivax Merozoite Surface Protein-1 (MSP1(19)) and the Salmonella enterica serovar Typhimurium flagellin (FliC), a Toll-like receptor 5 (TLR5) agonist. FliC was used as an adjuvant either admixed or genetically linked to the P. vivax MSP1(19) and administered to C57BL/6 mice via parenteral (s.c.) or mucosal (i.n.) routes. The recombinant fusion protein preserved MSP1(19) epitopes recognized by sera collected from P. vivax infected humans and TLR5 agonist activity. Mice parenterally immunized with recombinant P. vivax MSP1(19) in the presence of FliC, either admixed or genetically linked, elicited strong and long-lasting MSP1(19)-specific systemic antibody responses with a prevailing IgG1 subclass response. Incorporation of another TLR agonist, CpG ODN 1826, resulted in a more balanced response, as evaluated by the IgG1/IgG2c ratio, and higher cell-mediated immune response measured by interferon-gamma secretion. Finally, we show that MSP1(19)-specific antibodies recognized the native protein expressed on the surface of P. vivax parasites harvested from infected humans. The present report proposes a new class of malaria vaccine formulation based on the use of malarial antigens and the innate immunity agonist FliC. It contains intrinsic adjuvant properties and enhanced ability to induce specific humoral and cellular immune responses when administered alone or in combination with other adjuvants.
Bargieri
Daniel Y
DY
Centro Interdisciplinar de Terapia Gênica (CINTERGEN), Universidade Federal de São Paulo, Escola Paulista de Medicina, Rua Mirassol 207, São Paulo, SP, Brazil.
Rosa
Daniela S
DS
Braga
Catarina J M
CJ
Carvalho
Bruna O
BO
Costa
Fabio T M
FT
Espíndola
Noeli Maria
NM
Vaz
Adelaide José
AJ
Soares
Irene S
IS
Ferreira
Luis C S
LC
Rodrigues
Mauricio M
MM
D000276:Adjuvants, Immunologic; D000281:Administration, Intranasal; D000818:Animals; D000911:Antibodies, Monoclonal / Q000096:biosynthesis / Q000276:immunology; D002626:Chemistry, Pharmaceutical; D005260:Female; D005408:Flagellin / Q000302:isolation & purification / Q000494:pharmacology*; D019084:Fluorescent Antibody Technique, Indirect; D007115:Immunization Schedule; D007279:Injections, Subcutaneous; D017780:Malaria Vaccines / Q000008:administration & dosage / Q000235:genetics / Q000276:immunology*; D020066:Merozoite Surface Protein 1 / Q000235:genetics / Q000276:immunology*; D051379:Mice; D008810:Mice, Inbred C57BL; D010966:Plasmodium vivax / Q000235:genetics / Q000276:immunology*; D012486:Salmonella typhimurium / Q000378:metabolism*; D018417:Th1 Cells / Q000276:immunology; D018418:Th2 Cells / Q000276:immunology; D051198:Toll-Like Receptor 5 / Q000819:agonists*; D014614:Vaccines, Synthetic / Q000276:immunology
D000276:Adjuvants, Immunologic; D000911:Antibodies, Monoclonal; D017780:Malaria Vaccines; D020066:Merozoite Surface Protein 1; D051198:Toll-Like Receptor 5; D014614:Vaccines, Synthetic; D005408:Flagellin