Edmund K. Hainisch

Inoculation of young horses with bovine papillomavirus type 1 virions leads to early infection of PBMCs prior to pseudo-sarcoid formation

Bovine papillomavirus types 1 and 2 (BPV-1 and BPV-2) are known to induce common equine skin tumours, termed sarcoids. Recently, it was demonstrated that vaccination with BPV-1 virus-like particles (VLPs) is safe and highly immunogenic in horses. To establish a BPV-1 challenge model for evaluation of the protective potential of BPV-1 VLPs, four foals were injected intradermally with infectious BPV-1 virions and with viral genome-based and control inocula, and monitored daily for tumour development. Blood was taken before inoculation and at weekly intervals. BPV-1-specific serum antibodies were detected by a pseudo-virion neutralization assay. Total nucleic acids extracted from tumours, intact skin and PBMCs were tested for the presence of BPV-1 DNA and mRNA using PCR and RT-PCR, respectively. Intralesional E5 oncoprotein expression was determined by immunofluorescence. Pseudo-sarcoids developed exclusively at sites inoculated with virions. Tumours became palpable 11-32 days after virion challenge, reached a size of ≤20 mm in diameter and then resolved in ≤6 months. No neutralizing anti-BPV-1 serum antibodies were detectable pre- or post-challenge. BPV-1 DNA was present in lesions but not in intact skin. In PBMCs, viral DNA was already detectable before lesions were first palpable, in concentrations correlating directly with tumour growth kinetics. PBMCs from two of two foals also harboured E5 mRNA. Immunofluorescence revealed the presence of the E5 protein in tumour fibroblasts, but not in the apparently normal epidermis overlying the lesions. Together with previous findings obtained in horses and cows, these data suggest that papillomavirus infection may include a viraemic phase.

Potential of a BPV1 L1 VLP vaccine to prevent BPV1- or BPV2-induced pseudo-sarcoid formation and safety and immunogenicity of EcPV2 L1 VLPs in horse

We have previously shown that immunization of horses with BPV1 L1 virus-like particles (VLP) is safe and highly immunogenic, and that bovine papillomavirus types 1 and 2 (BPV1, BPV2) are closely related serotypes. Here we evaluated the protective potential of a BPV1 L1 VLP vaccine against experimental BPV1 and BPV2 challenge, and studied the safety and immunogenicity of a bivalent EcPV2/BPV1 L1 VLP vaccine. Fourteen healthy horses were immunized with BPV1 L1 VLPs (100 µg/injection) plus adjuvant on days 0 and 28, whilst seven remained unvaccinated. On day 42, all 21 horses were challenged intradermally at ten sites of the neck with 107 BPV1 virions per injection. In analogy, 14 horses immunized twice with EcPV2 plus BPV1 L1 VLPs (50 µg each) and seven control animals were challenged with 107 BPV2 virions/injection. Immunization with BPV1 L1 VLPs alone induced a robust antibody response (day-42 median titre: 12,800) and BPV1-inoculated skin remained unchanged in 13/14 vaccinated horses. Immunization with the bivalent vaccine was safe, resulted in lower median day-42 antibody titres of 400 for BPV1, and 1600 for EcPV2, and conferred significant yet incomplete cross-protection from BPV2-induced tumour formation, with 11/14 horses developing small, short-lived papules. Control horses developed pseudo-sarcoids at all inoculation sites. The monovalent BPV1 L1 VLP vaccine proved highly effective in protecting horses from BPV1-induced pseudo-sarcoid formation. Incomplete protection from BPV2-induced tumour development conferred by the bivalent vaccine is due to the poorer immune response by immune interference or lower cross-neutralization titres to heterologous BPV2 virions.We have previously shown that immunization of horses with bovine papillomavirus type 1 (BPV1) L1 virus-like particles (VLPs) is safe and highly immunogenic and that BPV1 and bovine papillomavirus type 2 (BPV2) are closely related serotypes. Here we evaluated the protective potential of a BPV1 L1 VLP vaccine against experimental BPV1 and BPV2 challenge and studied the safety and immunogenicity of a bivalent equine papillomavirus type 2 (EcPV2)/BPV1 L1 VLP vaccine. Fourteen healthy horses were immunized with BPV1 L1 VLPs (100 µg per injection) plus adjuvant on days 0 and 28, while seven remained unvaccinated. On day 42, all 21 horses were challenged intradermally at 10 sites of the neck with 107 BPV1 virions per injection. In analogy, 14 horses immunized twice with EcPV2 plus BPV1 L1 VLPs (50 µg each) and seven control animals were challenged with 107 BPV2 virions per injection. Immunization with BPV1 L1 VLPs alone induced a robust antibody response (day 42 median titre: 12 800), and BPV1-inoculated skin remained unchanged in 13/14 vaccinated horses. Immunization with the bivalent vaccine was safe, resulted in lower median day 42 antibody titres of 400 for BPV1 and 1600 for EcPV2 and conferred significant yet incomplete cross-protection from BPV2-induced tumour formation, with 11/14 horses developing small, short-lived papules. Control horses developed pseudo-sarcoids at all inoculation sites. The monovalent BPV1 L1 VLP vaccine proved highly effective in protecting horses from BPV1-induced pseudo-sarcoid formation. Incomplete protection from BPV2-induced tumour development conferred by the bivalent vaccine is due to the poorer immune response by immune interference or lower cross-neutralization titres to heterologous BPV2 virions.

Bacterial meningitis after sinus surgery in five adult horses.

OBJECTIVE To report meningoencephalitis as a complication after paranasal sinus surgery in 5 horses. STUDY DESIGN Case series. ANIMALS Adult horses (n = 5). METHODS Medical records (2005-2010) of 5 horses that developed neurologic signs after sinus surgery were reviewed to identify potential risk factors, cause(s), or common pathways for infection. RESULTS Underlying diseases were primary (n = 1) and secondary sinusitis (4) because of apical dental infection (1), sinus cyst (2), or masses in the ethmoturbinate region (2). Horses were treated by conventional surgical approaches and aftercare including repeated sinus lavage. Four horses had undulating pyrexia postoperatively despite antimicrobial therapy. All horses developed neurologic signs, eventually unresponsive to treatment. Suppurative meningoencephalitis was diagnosed macro- and/or microscopically on necropsy in all horses. CONCLUSION Meningitis is a rare but fatal complication after sinus surgery in horses.Objective To report meningoencephalitis as a complication after paranasal sinus surgery in 5 horses. Study Design Case series. Animals Adult horses (n = 5). Methods Medical records (2005–2010) of 5 horses that developed neurologic signs after sinus surgery were reviewed to identify potential risk factors, cause(s), or common pathways for infection. Results Underlying diseases were primary (n = 1) and secondary sinusitis (4) because of apical dental infection (1), sinus cyst (2), or masses in the ethmoturbinate region (2). Horses were treated by conventional surgical approaches and aftercare including repeated sinus lavage. Four horses had undulating pyrexia postoperatively despite antimicrobial therapy. All horses developed neurologic signs, eventually unresponsive to treatment. Suppurative meningoencephalitis was diagnosed macro- and/or microscopically on necropsy in all horses. Conclusion Meningitis is a rare but fatal complication after sinus surgery in horses.

Prophylactic Vaccination Against Papillomavirus-Induced Tumour Disease

The Papillomaviridae family comprises a large number of genetically heterogeneous papillomaviruses (PVs) that are the causative agents of benign lesions or cancer in humans and a wide range of animal species. Early research in animal PV systems has disclosed several important characteristics of PVs and led to the recognition of human papillomaviruses (HPVs) as carcinogenic viruses in 1995. One of the most crucial findings in animals was that in vitro generated PV major capsid proteins spontaneously self-assemble to empty viral capsids termed virus-like particles (VLPs) that are safe and highly immunogenic. This discovery paved the way for the establishment and commercial release of highly effective polyvalent VLP-based vaccines for the prevention of HPV-induced tumour disease in humans. In addition, it encouraged veterinary scientists to work on the establishment of analogous, VLP-based vaccines for the protection of horses and other equids from common PV-induced cutaneous and mucosal tumours that is bovine PV type 1/2 (BPV1/2)-associated sarcoids and equine PV type 2 (EcPV2)-induced squamous cell carcinomas (SCCs). So far, BPV1 and EcPV2 VLPs were shown to be safe and highly immunogenic in horses. Furthermore, immunisation of horses with BPV1 VLPs conferred complete protection from experimental BPV1 infection and associated pseudo-sarcoid formation and also elicited cross protection from BPV2 infection. Similarly, the protective potential of EcPV2 VLPs against experimental infection with EcPV2 pseudo-virions was shown in a murine model. Taken together, these findings indicate that BPV1 and EcPV2 VLPs are safe and highly effective in protecting equids from PV-induced sarcoids and SCCs.

Type-specific L1 virus-like particle-mediated protection of horses from experimental bovine papillomavirus 1-induced pseudo-sarcoid formation is long-lasting

Equine sarcoids are common therapy-resistant skin tumours induced by bovine papillomavirus type 1 or 2 (BPV1, BPV2) infection. We have previously shown that prophylactic vaccination with BPV1 L1 virus-like particles (VLPs) efficiently protects horses from experimental BPV1-induced pseudo-sarcoid development. Here, we assessed BPV1 L1 VLP vaccine-mediated long-term protection from experimental tumour formation in seven horses 5 years after immunization with three different doses of BPV1 L1 VLPs, and three unvaccinated control animals. Horses were challenged by intradermal inoculation with infectious BPV1 virions at 10 sites on the neck (106 virions per injection). In vaccinated horses, BPV1 challenge did not result in any apparent lesions irrespective of vaccine dosage and BPV1-neutralizing antibody titres that had dropped considerably over time and below the detection limit in one individual. Control horses developed pseudo-sarcoids at all inoculation sites. We conclude that immunization of horses with BPV1 L1 VLPs induces long-lasting protection against experimental BPV1 virion-induced disease.

Bacterial Meningitis After Sinus Surgery in Five Adult Horses: Bacterial Meningitis After Sinus Surgery

OBJECTIVE To report meningoencephalitis as a complication after paranasal sinus surgery in 5 horses. STUDY DESIGN Case series. ANIMALS Adult horses (n = 5). METHODS Medical records (2005-2010) of 5 horses that developed neurologic signs after sinus surgery were reviewed to identify potential risk factors, cause(s), or common pathways for infection. RESULTS Underlying diseases were primary (n = 1) and secondary sinusitis (4) because of apical dental infection (1), sinus cyst (2), or masses in the ethmoturbinate region (2). Horses were treated by conventional surgical approaches and aftercare including repeated sinus lavage. Four horses had undulating pyrexia postoperatively despite antimicrobial therapy. All horses developed neurologic signs, eventually unresponsive to treatment. Suppurative meningoencephalitis was diagnosed macro- and/or microscopically on necropsy in all horses. CONCLUSION Meningitis is a rare but fatal complication after sinus surgery in horses.Objective To report meningoencephalitis as a complication after paranasal sinus surgery in 5 horses. Study Design Case series. Animals Adult horses (n = 5). Methods Medical records (2005–2010) of 5 horses that developed neurologic signs after sinus surgery were reviewed to identify potential risk factors, cause(s), or common pathways for infection. Results Underlying diseases were primary (n = 1) and secondary sinusitis (4) because of apical dental infection (1), sinus cyst (2), or masses in the ethmoturbinate region (2). Horses were treated by conventional surgical approaches and aftercare including repeated sinus lavage. Four horses had undulating pyrexia postoperatively despite antimicrobial therapy. All horses developed neurologic signs, eventually unresponsive to treatment. Suppurative meningoencephalitis was diagnosed macro- and/or microscopically on necropsy in all horses. Conclusion Meningitis is a rare but fatal complication after sinus surgery in horses.