Protective cell-mediated immunity by DNA vaccination against Papillomavirus L1 capsid protein in the Cottontail Rabbit Papillomavirus model.

Department of Pathology, Jake Gittlen Cancer Research Foundation, Pennsylvania State University College of Medicine, Hershey, Pennsylvania 17033, USA.
Viral Immunology (Impact Factor: 1.64). 02/2006; 19(3):492-507. DOI: 10.1089/vim.2006.19.492
Source: PubMed

ABSTRACT Papillomavirus major capsid protein L1 has successfully stimulated protective immunity against virus infection by induction of neutralizing antibodies in animal models and in clinical trials. However, the potential impact of L1-induced protective cell-mediated immune (CMI) responses is difficult to measure in vivo because of the coincidence of anti-L1 antibody. In this study, we tested the hypothesis that L1 could activate CMI, using the Cottontail Rabbit Papillomavirus (CRPV)-rabbit model. A unique property of this model is that infections can be initiated with viral DNA, thus bypassing all contributions to protection via neutralizing anti-L1 antibody. DNA vaccines containing either CRPV L1, or subfragments of L1 (amino-terminal two-thirds of L1 [L1N] and the carboxylterminal two-thirds of L1 [L1C]), were delivered intracutaneously into rabbits, using a gene gun. After three booster immunizations, the rabbits were challenged with several viral DNA constructs: wild-type CRPV, CRPV L1ATGko (an L1 ATG knockout mutation), and CRPV-ROPV hybrid (CRPV with a replacement L1 from Rabbit Oral Papillomavirus). Challenge of L1 DNA-vaccinated rabbits with wild-type CRPV resulted in significantly fewer papillomas when compared with challenge with CRPV L1ATGko DNA. Significantly smaller papillomas were found in CRPV L1-, L1N-, and L1C-vaccinated rabbits. In addition, rabbits vaccinated with either L1 or L1N grew significantly fewer and smaller papillomas when challenged with CRPV-ROPV hybrid DNA. Therefore, CRPV L1 DNA vaccination induced CMI responses to CRPV DNA infections that can contribute to protective immunity. Cross-protective immunity against CRPV L1 and ROPV L1 was elicited in these CRPV L1- and subfragment-vaccinated rabbits.

Download full-text


Available from: Jiafen Hu, Mar 25, 2015
  • Source
    • "Papillomas induced by wild type CRPV DNA and mutant mixtures were harvested and fixed in 10% formalin. The tissue was processed as reported previously (Hu, Cladel et al., 2006). "
    [Show abstract] [Hide abstract]
    ABSTRACT: Recent phylogenic studies indicate that DNA recombination could have occurred in ancient papillomavirus types. However, no experimental data are available to demonstrate this event because of the lack of human papillomavirus infection models. We have used the cottontail rabbit papillomavirus (CRPV)/rabbit model to study pathogenesis and immunogenicity of different mutant genomes in vivo. Although the domestic rabbit is not a natural host for CRPV infection, it is possible to initiate infection with naked CRPV DNA cloned into a plasmid and monitor papilloma outgrowth on these animals. Taking advantage of a large panel of mutants based on a CRPV strain (Hershey CRPV), we tested the hypothesis that two non-viable mutant genomes could induce papillomas by either recombination or complementation. We found that co-infection with a dysfunctional mutant with an E2 transactivation domain mutation and another mutant with an E7 ATG knock out generated papillomas in rabbits. DNA extracted from these papillomas contained genotypes from both parental genomes. Three additional pairs of dysfunctional mutants also showed similar results. Individual wild type genes were also shown to rescue the function of corresponding dysfunctional mutants. Therefore, we suggest that complementation occurred between these two non-viable mutant PV genomes in vivo.
    Virus Research 05/2009; 144(1-2):117-22. DOI:10.1016/j.virusres.2009.04.006 · 2.83 Impact Factor
  • Source
    • "These antibodies helped us to better detect L1 in both virion-and DNA-infected domestic rabbit papillomas. In some cases, the expression level of L1 was as high as that observed in cottontail rabbit papillomas (Hu et al., 2006b). "
    [Show abstract] [Hide abstract]
    ABSTRACT: Shope papillomavirus or cottontail rabbit papillomavirus (CRPV) is one of the first small DNA tumour viruses to be characterized. Although the natural host for CRPV is the cottontail rabbit (Sylvilagus floridanus), CRPV can infect domestic laboratory rabbits (Oryctolagus cuniculus) and induce tumour outgrowth and cancer development. In previous studies, investigators attempted to passage CRPV in domestic rabbits, but achieved very limited success, leading to the suggestion that CRPV infection in domestic rabbits was abortive. The persistence of specific anti-L1 antibody in sera from rabbits infected with either virus or viral DNA led us to revisit the questions as to whether L1 and infectious CRPV can be produced in domestic rabbit tissues. We detected various levels of L1 protein in most papillomas from CRPV-infected rabbits using recently developed monoclonal antibodies. Sensitive in vitro infectivity assays additionally confirmed that extracts from these papillomas were infectious. These studies demonstrated that the CRPV/New Zealand White rabbit model could be used as an in vivo model to study natural virus infection and viral life cycle of CRPV and not be limited to studies on abortive infections.
    Journal of General Virology 01/2008; 88(Pt 12):3286-93. DOI:10.1099/vir.0.82879-0 · 3.53 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: For more than a decade, community groups, scientific organizations and government agencies have collaborated to repopulate the endangered western barred bandicoot (Perameles bougainville). While initially successful, the unexpected discovery of a papillomatosis and carcinomatosis syndrome in captive and wild populations of P. bougainville exposed a dearth of knowledge regarding their diseases. This dissertation addresses this issue through study of the clinical pathology, immunology, parasitology, and virology of P. bougainville. To facilitate the detection and understanding of diseases in P. bougainville, guidelines for interpreting haematology and clinical chemistry results were developed, including calculated species-specific reference intervals for plasma aspartate transaminase activity (20-283 U/L), haemoglobin (122-165 g/L), haematocrit (0.36-0.49 L/L), total leukocytes (2.9-14.9 x10^9/L), monocytes (0-0.6 x10^9/L), eosinophils (0-0.9 x10^9/L) and total protein (47-63 g/L) estimated by refractometry. P. bougainville immunoglobulin was also fractionated from plasma and inoculated into sheep to derive antiserum for serological screening assays. Arthropods, helminths and protozoa parasitic on P. bougainville were catalogued and Eimeria kanyana n. sp. was formally described. The pathogenic and zoonotic potential of bacteria detected in ticks parasitic on P. bougainville was also considered. The association between bandicoot papillomatosis carcinomatosis virus type 1 (BPCV1) and the western barred bandicoot papillomatosis and carcinomatosis syndrome was investigated using PCR, in situ hybridization and virus isolation. Optimized in situ hybridization techniques demonstrated BPCV1 DNA within keratinocyte and sebocyte nuclei, and BPCV1 mRNA within the cytoplasm. BPCV1 virions were isolated by ultracentrifugation and visualized with negative stain transmission electron microscopy revealing icosahedral, non-enveloped viral capsids ~47 nm in diameter, comparable to viruses classified within Papillomaviridae and Polyomaviridae. A novel virus, tentatively named bandicoot papillomatosis carcinomatosis virus type 2 (BPCV2) was discovered in papillomatous lesions from a southern brown bandicoot (Isoodon obesulus). It had a circular double-stranded DNA genome of 7277 bp, and encoded two papillomavirus-like structural proteins, L1 and L2, and two polyomavirus-like putative transforming proteins, large T antigen and small t antigen. DNA and RNA in situ hybridization confirmed the presence of BPCV2 nucleic acids within lesion biopsies. The discovery of the bandicoot papillomatosis carcinomatosis viruses has provoked reassessment of the established virus taxonomy paradigm, theories of virus-host co-speciation and bandicoot population management strategies.
Show more