title: Immunogenicity of chloroplast-derived HIV-1 p24 and a p24-Nef fusion protein following subcutaneous and oral administration in mice.
abstract: High-level expression of foreign proteins in chloroplasts of transplastomic plants provides excellent opportunities for the development of oral vaccines against a range of debilitating or fatal diseases. The HIV-1 capsid protein p24 and a fusion of p24 with the negative regulatory protein Nef (p24-Nef) accumulate to ∼4% and ∼40% of the total soluble protein of leaves of transplastomic tobacco (Nicotiana tabacum L.) plants. This study has investigated the immunogenicity in mice of these two HIV-1 proteins, using cholera toxin B subunit as an adjuvant. Subcutaneous immunization with purified chloroplast-derived p24 elicited a strong antigen-specific serum IgG response, comparable to that produced by Escherichia coli-derived p24. Oral administration of a partially purified preparation of chloroplast-derived p24-Nef fusion protein, used as a booster after subcutaneous injection with either p24 or Nef, also elicited strong antigen-specific serum IgG responses. Both IgG1 and IgG2a subtypes, associated with cell-mediated Th1 and humoral Th2 responses, respectively, were found in sera after subcutaneous and oral administration. These results indicate that chloroplast-derived HIV-1 p24-Nef is a promising candidate as a component of a subunit vaccine delivered by oral boosting, after subcutaneous priming by injection of p24 and/or Nef.
authors: Department of Plant Sciences, University of Cambridge, Cambridge, UK.
authors: Nuria
authors: N
authors: Gonzalez-Rabade
authors: Edward G
authors: EG
authors: McGowan
authors: Fei
authors: F
authors: Zhou
authors: Matthew S
authors: MS
authors: McCabe
authors: Ralph
authors: R
authors: Bock
authors: Philip J
authors: PJ
authors: Dix
authors: John C
authors: JC
authors: Gray
authors: Julian K-C
authors: JK
authors: Ma
mesh_terms: D016915:AIDS Vaccines / Q000008:administration & dosage* / Q000235:genetics / Q000276:immunology*; D000276:Adjuvants, Immunologic / Q000008:administration & dosage; D000284:Administration, Oral; D000818:Animals; D002736:Chloroplasts / Q000235:genetics* / Q000276:immunology; D005260:Female; D016655:HIV Core Protein p24 / Q000008:administration & dosage / Q000235:genetics / Q000276:immunology*; D056724:Immunity, Humoral / Q000276:immunology; D007117:Immunization, Secondary; D007279:Injections, Subcutaneous; D051379:Mice; D008807:Mice, Inbred BALB C; D008810:Mice, Inbred C57BL; D009538:Nicotine / Q000633:toxicity; D030821:Plants, Genetically Modified / Q000235:genetics; D014026:Nicotiana / Q000235:genetics; D054311:nef Gene Products, Human Immunodeficiency Virus / Q000008:administration & dosage / Q000235:genetics / Q000276:immunology*
chemical_list: D016915:AIDS Vaccines; D000276:Adjuvants, Immunologic; D016655:HIV Core Protein p24; D054311:nef Gene Products, Human Immunodeficiency Virus; C514837:nef protein, Human immunodeficiency virus 1; C514799:p24 protein, Human Immunodeficiency Virus Type 1; D009538:Nicotine