title: Ether lipid vesicle-based antigens impart protection against experimental listeriosis.
abstract: BACKGROUND
  Incidence of food-borne infections from Listeria monocytogenes, a parasite that has adapted intracellular residence to avoid antibody onslaught, has increased dramatically in the past few years. The apparent lack of an effective vaccine that is capable of evoking the desired cytotoxic T cell response to obliterate this intracellular pathogen has encouraged the investigation of alternate prophylactic strategies. It should also be noted that Archaebacteria (Archae) lipid-based adjuvants enhance the efficacy of subunit vaccines. In the present study, the adjuvant properties of archaeosomes (liposomes prepared from total polar lipids of archaebacteria, Halobacterium salinarum) combined with immunogenic culture supernatant antigens of L. monocytogenes have been exploited in designing a vaccine candidate against experimental listeriosis in murine model.
  
  
  METHODS
  Archaeosome-entrapped secretory protein antigens (SAgs) of L. monocytogenes were evaluated for their immunological responses and tendency to deplete bacterial burden in BALB/c mice challenged with sublethal listerial infection. Various immunological studies involving cytokine profiling, lymphocyte proliferation assay, detection of various surface markers (by flowcytometric analysis), and antibody isotypes (by enzyme-linked immunosorbent assay) were used for establishing the vaccine potential of archaeosome-entrapped secretory proteins.
  
  
  RESULTS
  Immunization schedule involving archaeosome-encapsulated SAgs resulted in upregulation of Th1 cytokine production along with boosted memory in BALB/c mice. It also showed protective effect by reducing listerial burden in various vital organs (liver and spleen) of the infected mice. However, the soluble form of the antigens (SAgs) and their physical mixture with sham (empty) archaeosomes, besides showing feeble Th1 response, were unable to protect the animals against virulent listerial infection.
  
  
  CONCLUSIONS
  On the basis of the evidence provided by the current data, it is inferred that archaeosome-entrapped SAgs formulation not only enhances cytotoxic T cell response but also helps in the clearance of pathogens and thereby increases the survival of the immunized animals.
authors: Interdisciplinary Biotechnology Unit, Aligarh Muslim University, Aligarh, UP, India.
authors: Mairaj Ahmed
authors: MA
authors: Ansari
authors: Swaleha
authors: S
authors: Zubair
authors: Saba
authors: S
authors: Tufail
authors: Ejaj
authors: E
authors: Ahmad
authors: Mohsin Raza
authors: MR
authors: Khan
authors: Zainuddin
authors: Z
authors: Quadri
authors: Mohammad
authors: M
authors: Owais
mesh_terms: D000704:Analysis of Variance; D000818:Animals; D000942:Antigens, Bacterial / Q000737:chemistry / Q000276:immunology*; D015703:Antigens, CD / Q000276:immunology; D001428:Bacterial Vaccines / Q000008:administration & dosage* / Q000737:chemistry / Q000276:immunology*; D015153:Blotting, Western; D049109:Cell Proliferation; D016207:Cytokines / Q000378:metabolism; D004591:Electrophoresis, Polyacrylamide Gel; D005260:Female; D005434:Flow Cytometry; D006217:Halobacterium / Q000737:chemistry; D007156:Immunologic Memory; D008081:Liposomes / Q000008:administration & dosage / Q000737:chemistry / Q000276:immunology; D008089:Listeria monocytogenes / Q000737:chemistry / Q000276:immunology*; D008088:Listeriosis / Q000276:immunology / Q000517:prevention & control*; D051379:Mice; D008807:Mice, Inbred BALB C; D018417:Th1 Cells / Q000276:immunology / Q000378:metabolism
chemical_list: D000942:Antigens, Bacterial; D015703:Antigens, CD; D001428:Bacterial Vaccines; D016207:Cytokines; D008081:Liposomes