Lambdapapillomavirus 2 in a Gray Wolf ( Canis lupus ) from Minnesota, USA with Oral Papillomatosis and Sarcoptic Mange.

Oral papillomatosis was diagnosed in a gray wolf ( Canis lupus ) with sarcoptic mange from Minnesota, US found dead in February 2015. Intranuclear inclusion bodies were evident histologically, and papillomaviral antigens were confirmed using immunohistochemistry. Sequencing of the L1 papillomavirus gene showed closest similarity to Lambdapapillomavirus 2.

Recent advances in preclinical model systems for papillomaviruses.

Preclinical model systems to study multiple features of the papillomavirus life cycle have greatly aided our understanding of Human Papillomavirus (HPV) biology, disease progression and treatments. The challenge to studying HPV in hosts is that HPV along with most PVs are both species and tissue restricted. Thus, fundamental properties of HPV viral proteins can be assessed in specialized cell culture systems but host responses that involve innate immunity and host restriction factors requires preclinical surrogate models. Fortunately, there are several well-characterized and new animal models of papillomavirus infections that are available to the PV research community. Old models that continue to have value include canine, bovine and rabbit PV models and new rodent models are in place to better assess host-virus interactions. Questions arise as to the strengths and weaknesses of animal PV models for HPV disease and how accurately these preclinical models predict malignant progression, vaccine efficacy and therapeutic control of HPV-associated disease. In this review, we examine current preclinical models and highlight the strengths and weaknesses of the various models as well as provide an update on new opportunities to study the numerous unknowns that persist in the HPV research field.

Antibody titres against canine papillomavirus 1 peak around clinical regression in naturally occurring oral papillomatosis.

BACKGROUND: Most forms of canine papillomatosis are believed to be associated with papillomavirus infections. Canine papillomavirus type 1 (CPV1) is considered to be responsible for most oral cases and several forms of cutaneous papillomatosis. HYPOTHESIS/OBJECTIVES: The aim of this study was to evaluate cases of naturally occurring oral papillomatosis with regard to the type of virus involved, antibody induction and remission time. METHODS: Forty dogs showing different degrees of classical oral papillomatosis were included as a single study group. Tissue and serum samples were acquired upon initial presentation; serum samples were collected again upon remission (n = 13) and after 3 months of convalescence (n = 4). None of the dogs underwent antiviral therapy. Tissue samples were tested by PCR to detect CPV DNA, while serum samples were tested using a specific enzyme-linked immunosorbent assay for antibodies against the L1 capsid protein of CPV1. RESULTS: All tissue samples were positive for CPV1 DNA, and 87.5% of all serum samples contained measurable levels of antibody against the virus (cut-off value 0.3). The average optical density measured in the enzyme-linked immunosorbent assay was 0.51 at initial presentation, 1.65 upon remission and 0.83 at 3 months postrecovery. Time to clinical regression varied between 1 month and 1 year. CONCLUSIONS AND CLINICAL IMPORTANCE: These data support existing evidence for a high prevalence of CPV1 in canine oral papillomatosis. The healing process seems to correlate with a strong antibody response, and antibody titres peaked around the time of clinical recovery. In contrast to previous data from laboratory settings, the variation in remission time was very high.

Amplicon-plus targeting technology (APTT) for rapid production of a highly unstable vaccine protein in tobacco plants.

High-level expression of transgenes is essential for cost-effective production of valuable pharmaceutical proteins in plants. However, transgenic proteins often accumulate in plants at low levels. Low levels of protein accumulation can be caused by many factors including post-transcriptional gene silencing (PTGS) and/or rapid turnover of the transgenic proteins. We have developed an Amplicon-plus Targeting Technology (APTT), by using novel combination of known techniques that appears to overcome both of these factors. By using this technology, we have successfully expressed the highly-labile L1 protein of canine oral papillomavirus (COPV L1) by infecting transgenic tobacco plants expressing a suppressor of post-transcriptional gene silencing (PTGS) with a PVX amplicon carrying a gene encoding L1, and targeting the vaccine protein into the chloroplasts. Further, a scalable "wound-and-agrospray" inoculation method has been developed that will permit high-throughput Agrobacterium inoculation of Nicotiana tabacum, and a spray-only method (named "agrospray") for use with N. benthamiana to allow large-scale application of this technology. The good yield and short interval from inoculation to harvest characteristic of APTT, combined with the potential for high-throughput achieved by use of the agrospray inoculation protocol, make this system a very promising technology for producing high value recombinant proteins, especially those known to be highly labile, in plants for a wide range of applications including producing vaccines against rapidly evolving pathogens and for the rapid response needed to meet bio-defense emergencies.

Cell-mediated immune responses to COPV early proteins.

Cell-mediated immunity plays a key role in the regression of papillomavirus-induced warts and intra-epithelial lesions but the target antigens that induce this response are not clear. Canine oral papillomavirus (COPV) infection of the oral cavity in dogs is a well-characterized model of mucosal papillomavirus infection that permits analysis of the immune events during the infectious cycle. In this study we show that during the COPV infectious cycle, systemic T cell responses to peptides of several early proteins particularly the E2 protein, as assayed by delayed type hypersensitivity, lymphoproliferation and IFN-gamma ELISPOT, can be detected. The maximal response occurs in a narrow time window that coincides with maximal viral DNA replication and wart regression: thereafter, systemic T cell responses to early proteins decline quite rapidly. Vaccination using particle-mediated immunotherapeutic delivery (PMID) of codon-modified COPV E2 and E1 genes induces strong antigen-specific cell-mediated immune responses in the vaccinated animals. These data show that therapeutic immunization by PMID with codon-modified E2 is completely effective, that to E1 is partially protective, that this correlates with the intensity of antigen-specific cell-mediated immune responses and, further, they emphasize the importance of these responses and the route of immunization in the generation of protective immunity.