title: Attenuated Listeria monocytogenes vaccine vectors expressing influenza A nucleoprotein: preclinical evaluation and oral inoculation of volunteers.
abstract: Listeria monocytogenes vectors have shown promise for delivery of viral and tumor antigens in animals. We used two mutant vector strains deleted for actA/plcB (BMB72) and actA/inlB (BMB54), and engineered both strains to secrete a heterologous nucleoprotein antigen from the Influenza A virus. Strains were evaluated in vitro and in mice. Twenty-two healthy volunteers received single oral doses of either strain in a physiological study of safety, shedding, and immunogenicity. Volunteers were observed in the hospital for seven days and had daily blood cultures, routine safety blood tests (complete blood count with differential; hepatic and renal function), and fecal cultures; none had fever, positive blood cultures, prolonged shedding, or serious or unexpected events. Four of 12 volunteers who received the actA/plcB-deleted strain had minor, transient, asymptomatic serum transaminase elevations (maximum increase 1.4× upper normal). Six of six volunteers who received ≥4 × 10(9) colony forming units had detectable mucosal immune responses to listerial antigens, but not to the vectored influenza antigen. Approximately half the volunteers had modest interferon-γ ELISpot responses to a complex listerial antigen, but none had increases over their baseline responses to the influenza antigen. Comparison with prior work suggests that foreign antigen expression, and perhaps also freezing, may adversely affect the organisms' immunogenicity.
authors.affiliation: Division of Infectious Diseases, Department of Medicine, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02114, USA.
authors.forename: Paul V
authors.initials: PV
authors.lastname: Johnson
authors.forename: Barbra M
authors.initials: BM
authors.lastname: Blair
authors.forename: Skye
authors.initials: S
authors.lastname: Zeller
authors.forename: Camille N
authors.initials: CN
authors.lastname: Kotton
authors.forename: Elizabeth L
authors.initials: EL
authors.lastname: Hohmann
mesh_terms: D000818:Animals; D000917:Antibody Formation / Q000276:immunology; D001427:Bacterial Toxins / Q000235:genetics / Q000276:immunology / Q000378:metabolism; D004353:Drug Evaluation, Preclinical; D058501:Enzyme-Linked Immunospot Assay; D005822:Genetic Vectors / Q000008:administration & dosage / Q000009:adverse effects* / Q000276:immunology; D006360:Heat-Shock Proteins / Q000235:genetics / Q000276:immunology / Q000378:metabolism; D006460:Hemolysin Proteins / Q000235:genetics / Q000276:immunology / Q000378:metabolism; D006801:Humans; D018928:Immunity, Mucosal; D007074:Immunoglobulin G / Q000096:biosynthesis; D007252:Influenza Vaccines / Q000008:administration & dosage / Q000009:adverse effects* / Q000235:genetics / Q000276:immunology; D007371:Interferon-gamma / Q000096:biosynthesis*; D008089:Listeria monocytogenes / Q000235:genetics* / Q000276:immunology / Q000378:metabolism; D051379:Mice; D019590:Nucleocapsid Proteins; D016601:RNA-Binding Proteins / Q000009:adverse effects* / Q000235:genetics / Q000276:immunology / Q000378:metabolism; D016896:Treatment Outcome; D014611:Vaccination; D014613:Vaccines, Attenuated / Q000008:administration & dosage / Q000009:adverse effects* / Q000235:genetics / Q000276:immunology / Q000378:metabolism; D014758:Viral Core Proteins / Q000009:adverse effects* / Q000235:genetics / Q000276:immunology / Q000378:metabolism
chemical_list: D001427:Bacterial Toxins; D006360:Heat-Shock Proteins; D006460:Hemolysin Proteins; D007074:Immunoglobulin G; D007252:Influenza Vaccines; C048842:NP protein, Influenza A virus; D019590:Nucleocapsid Proteins; D016601:RNA-Binding Proteins; D014613:Vaccines, Attenuated; D014758:Viral Core Proteins; D007371:Interferon-gamma; C038705:hlyA protein, Listeria monocytogenes