title: Expression of the Plasmodium falciparum immunodominant epitope (NANP)(4) on the surface of Salmonella enterica using the autotransporter MisL.
abstract: Gram-negative bacterial proteins which are exported from the cytosol to the external environment by the type V secretion system are also known as autotransporters. Once translocated to the periplasmic compartment by the sec-dependent general secretory pathway, their C-terminal domain forms a pore through which the N-terminal domain travels to the outer membrane without the need of other accessory proteins. MisL (protein of membrane insertion and secretion) is a protein of unknown function located in the pathogenicity island SPI-3 of Salmonella enterica and classified as an autotransporter due to its high homology to Escherichia coli AIDA-I. In the present work, the MisL C-terminal translocator domain was used to display the immunodominant B-cell epitope of the circumsporozoite protein (CSP) from Plasmodium falciparum on the surface of Salmonella enterica serovar Typhimurium (serovar Typhimurium SL3261) and serovar Typhi (serovar Typhi CVD 908). The MisL beta domain was predicted by alignment with AIDA-I, amplified from serovar Typhimurium SL3261, cloned in a plasmid fused to four repeats of the tetrapeptide NANP behind the Escherichia coli heat-labile enterotoxin B subunit signal peptide to ensure periplasmic traffic, and expressed under the control of the anaerobically inducible nirB promoter. The fusion protein was translocated to the outer membrane of both bacterial strains, although the foreign epitope was displayed more efficiently in serovar Typhimurium SL3261, which elicited a better specific antibody response in BALB/c mice. More importantly, antibodies were able to recognize the native CSP in P. falciparum sporozoites. These results confirm that MisL is indeed an autotransporter and that it can be used to express foreign immunogenic epitopes on the surface of gram-negative bacteria.
authors.affiliation: Unidad de Investigación Médica en Inmunología e Infectología, Hospital de Infectología Dr. Daniel Méndez Hernández, Centro Médico La Raza, Instituto Mexicano del Seguro Social, Mexico D.F., Mexico.
authors.forename: Fernando
authors.initials: F
authors.lastname: Ruiz-Pérez
authors.forename: Rocío
authors.initials: R
authors.lastname: León-Kempis
authors.forename: Araceli
authors.initials: A
authors.lastname: Santiago-Machuca
authors.forename: Guadalupe
authors.initials: G
authors.lastname: Ortega-Pierres
authors.forename: Eileen
authors.initials: E
authors.lastname: Barry
authors.forename: Myron
authors.initials: M
authors.lastname: Levine
authors.forename: César
authors.initials: C
authors.lastname: González-Bonilla
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D000913:Antibodies, Protozoan / Q000096:biosynthesis; D000953:Antigens, Protozoan / Q000235:genetics* / Q000276:immunology; D001426:Bacterial Proteins / Q000235:genetics / Q000276:immunology / Q000378:metabolism*; D001483:Base Sequence; D002352:Carrier Proteins / Q000235:genetics / Q000276:immunology / Q000378:metabolism*; D002462:Cell Membrane / Q000378:metabolism; D018076:DNA, Complementary; D018985:Epitopes, B-Lymphocyte / Q000235:genetics* / Q000276:immunology; D015870:Gene Expression; D005818:Genetic Engineering; D005822:Genetic Vectors / Q000235:genetics / Q000276:immunology / Q000378:metabolism*; D016056:Immunodominant Epitopes / Q000235:genetics* / Q000276:immunology; D017780:Malaria Vaccines / Q000235:genetics / Q000276:immunology; D026901:Membrane Transport Proteins; D051379:Mice; D008807:Mice, Inbred BALB C; D008969:Molecular Sequence Data; D010455:Peptides / Q000235:genetics / Q000276:immunology; D010963:Plasmodium falciparum / Q000235:genetics* / Q000276:immunology; D015800:Protozoan Proteins / Q000235:genetics* / Q000276:immunology; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000276:immunology; D012486:Salmonella typhimurium / Q000235:genetics / Q000276:immunology / Q000378:metabolism; D017386:Sequence Homology, Amino Acid; D014614:Vaccines, Synthetic / Q000235:genetics / Q000276:immunology
chemical_list: D000913:Antibodies, Protozoan; D000953:Antigens, Protozoan; D001426:Bacterial Proteins; D002352:Carrier Proteins; D018076:DNA, Complementary; D018985:Epitopes, B-Lymphocyte; D016056:Immunodominant Epitopes; D017780:Malaria Vaccines; D026901:Membrane Transport Proteins; C460865:MisL protein, Salmonella enterica; D010455:Peptides; D015800:Protozoan Proteins; D011993:Recombinant Fusion Proteins; D014614:Vaccines, Synthetic; C041595:circumsporozoite protein, Protozoan