RESUMEN
The native cottontail rabbit papillomavirus (CRPV) L1 capsid protein gene was expressed transgenically via Agrobacterium tumefaciens transformation and transiently via a tobacco mosaic virus (TMV) vector in Nicotiana spp. L1 protein was detected in concentrated plant extracts at concentrations up to 1.0 mg/kg in transgenic plants and up to 0.4 mg/kg in TMV-infected plants. The protein did not detectably assemble into viruslike particles; however, immunoelectron microscopy showed presumptive pentamer aggregates, and extracted protein reacted with conformation-specific and neutralizing monoclonal antibodies. Rabbits were injected with concentrated protein extract with Freund's incomplete adjuvant. All sera reacted with baculovirus-produced CRPV L1; however, they did not detectably neutralize infectivity in an in vitro assay. Vaccinated rabbits were, however, protected against wart development on subsequent challenge with live virus. This is the first evidence that a plant-derived papillomavirus vaccine is protective in an animal model and is a proof of concept for human papillomavirus vaccines produced in plants.
Asunto(s)
Agrobacterium tumefaciens/genética , Antígenos Virales , Inmunización , Vacunas/uso terapéutico , Proteínas Estructurales Virales , Animales , Antígenos Virales/genética , Antígenos Virales/inmunología , Antígenos Virales/uso terapéutico , Secuencia de Bases , Clonación Molecular , Técnicas de Transferencia de Gen , Datos de Secuencia Molecular , Plantas Modificadas Genéticamente , ARN/biosíntesis , Conejos , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa , Nicotiana/genética , Nicotiana/metabolismo , Nicotiana/virología , Virus del Mosaico del Tabaco/genética , Vacunas/genética , Vacunas/inmunología , Proteínas Estructurales Virales/genética , Proteínas Estructurales Virales/inmunología , Proteínas Estructurales Virales/uso terapéuticoRESUMEN
As cervical cancer is causally associated with 14 high-risk types of human papillomavirus (HPV), a successful HPV vaccine will have a major impact on this disease. Although some persistent HPV infections progress to cervical cancer, host immunity is generally able to clear most HPV infections. Both cell-mediated and antibody responses have been implicated in influencing the susceptibility, persistence or clearance of genital HPV infection. There have been two clinical trials that show that vaccines based on virus-like particles (VLPs) made from the major capsid protein, L1, are able to type specifically protect against cervical intra-epithelial neoplasia and infection. However, there is no evidence that even a mixed VLP vaccine will protect against types not included in the vaccine, and a major challenge that remains is how to engineer protection across a broader spectrum of viruses. Strategies for production of HPV vaccines using different vaccine vectors and different production systems are also reviewed.
Asunto(s)
Papillomaviridae/inmunología , Infecciones por Papillomavirus/prevención & control , Neoplasias del Cuello Uterino/prevención & control , Vacunas Virales/uso terapéutico , Anticuerpos Antivirales/inmunología , Vacunas Bacterianas/inmunología , Vacunas Bacterianas/uso terapéutico , Citocinas/inmunología , Femenino , Seropositividad para VIH/inmunología , Humanos , Inmunidad Celular/inmunología , Infecciones por Papillomavirus/inmunología , Fitoterapia/métodos , Neoplasias del Cuello Uterino/inmunología , Neoplasias del Cuello Uterino/virologíaRESUMEN
Complete nucleotide sequences of the DNA-A (2800 nt) and DNA-B (2760 nt) components of a novel cassava-infecting begomovirus, South African cassava mosaic virus (SACMV), were determined and compared with various New World and Old World begomoviruses. SACMV is most closely related to East African cassava mosaic virus (EACMV) in both its DNA-A (85% with EACMV-MH and -MK) and -B (90% with EACMV-UG2-Mld and EACMV-UG3-Svr) components; however, percentage sequence similarities of less than 90% in the DNA-A component allowed SACMV to be considered a distinct virus. One significant recombination event spanning the entire AC4 open reading frame was identified; however, there was no evidence of recombination in the DNA-B component. Infectivity of the cloned SACMV genome was demonstrated by successful agroinoculation of cassava and three other plant species (Phaseolus vulgaris, Malva parviflora and Nicotiana benthamiana). This is the first description of successful infection of cassava with a geminivirus using Agrobacterium tumefaciens.
Asunto(s)
Geminiviridae/genética , Genoma Viral , Manihot/virología , Agrobacterium tumefaciens/genética , Clonación Molecular , Fabaceae/virología , Geminiviridae/clasificación , Malvaceae/virología , Datos de Secuencia Molecular , Sistemas de Lectura Abierta , Filogenia , Plantas Medicinales , Plantas Tóxicas , Recombinación Genética , Nicotiana/virología , Transformación GenéticaRESUMEN
A technique for the detection of plant virus coat proteins in plant sap is described. The method entails the electroblotting of sodium dodecyl sulphate-polyacrylamide gel electrophoresis-fractionated plant extracts onto nitrocellulose paper, probing the paper with virus-specific rabbit antisera, and indirect detection of virus proteins with horseradish peroxidase-conjugated goat anti-rabbit globulins. The sensitivity and specificity of the technique were tested using brome mosaic and barley stripe mosaic viruses. As little as 1 ng per track of virus protein was detectable, either as pure virus or when mixed with plant sap. Distant serological relationships were detected amongst tobamoviruses, and amongst the bromoviruses, with single antisera. The uses of the technique in probing capsid configuration in a presumed aphid picornavirus, and in routine diagnostic practice, are described.