Recombinant Bovine Herpesvirus 4 (BoHV-4) Expressing Glycoprotein D of BoHV-1 Is Immunogenic and Elicits Serum-Neutralizing Antibodies against BoHV-1 in a Rabbit Model

Abstract

Several biological characteristics of bovine herpesvirus 4 (BoHV-4) make it a good candidate as a gene delivery vector for vaccination purposes. These characteristics include little or no pathogenicity, unlikely oncogenicity, the capability to accommodate large amounts of foreign genetic material, the ability to infect several cell types coming from different animal species, and the ability to maintain transgene expression in both undifferentiated and differentiated cells. Bovine herpesvirus 4 (BoHV-4) has been isolated from a variety of samples and cells from healthy cattle and from cattle that have experienced abortion or with metritis, pneumonia, diarrhea, respiratory infection, and mammary pustular dermatitis (reviewed in reference 35). The virus was first isolated in Europe from cattle with respiratory and ocular diseases by Bartha et al. (2) and later in the United States by Mohanty et al. (26). Subsequently, distinct BoHV-4 isolates were obtained both in Europe and in the United States (11,25,31,34). However, the pathogenic role of BoHV-4 remains unclear, and only a few investigators have successfully produced an experimental disease (reviewed in reference 35). Although BoHV-4 is classified as a gammaherpesvirus based on genome sequence (3, 13, 41), it differs from other Gammaherpesviridae members in important biological properties. Unlike most other gammaherpesviruses, BoHV-4 causes cytopathic effect (CPE) and replicates in a variety of primary cultures and cell lines of bovine and various other animal species (32). In addition, there is no evidence for oncogenicity or growth transformation by BoHV-4.In contrast to BoHV-4, BoHV-1, an alphaherpesvirus, is a major viral pathogen of cattle and causes significant economic losses worldwide (39). Infection is accompanied by various clinical manifestations, such as infectious bovine rhinotracheitis, infectious pustular vulvovaginitis, balanoposthitis, abortion, and generalized systemic infection. BoHV-1 is known to play an important role in the bovine respiratory disease complex, commonly referred to as shipping fever (39). Inflammation and necrosis of respiratory epithelia and immunosuppression often lead to increased susceptibility to secondary viral and bacterial infections, resulting in severe clinical disease.Due to its biological characteristics, BoHV-4 has been suggested as a gene delivery vector (7,9,14). In the present work, we explored the feasibility of employing BoHV-4 as a vector to deliver the immunodominant glycoprotein D (gD) of BoHV-1 and generated a model for BoHV-1 vaccination by BoHV-4 expressing BoHV-1 gD. MATERIALS AND METHODSViruses. Recombinants BoHV-4, wild-type BoHV-4 (strain LVR), and wildtype BoHV-1 (strain New York) were propagated by infecting confluent monolayers of Madin-Darby bovine kidney (MDBK) cells at a multiplicity of infection (MOI) of 0.5 50% tissue culture infectious doses (TCID 50 ) per cell and maintained in minimal essential medium (MEM) with 2% fetal bovine serum (FBS) for 2 h. The medium was then removed and replac...

Cellular Targeting of Engineered Heterologous Antigens Is a Determinant Factor for Bovine Herpesvirus 4-Based Vaccine Vector Development

“…HEK 293T cells were cultured and transfected as previously described (5). Thirty micrograms of pCMV-IgKE2gD-TM was electroporated in HEK 293T cells from a confluent 75-cm 2 flask, and a plasmid expressing green fluorescent protein (GFP) under the control of the cytomegalovirus (CMV) promoter (pEGFP-C1) was identically electroporated (Equibio apparatus; 186 V, 960 F, 4-mm-gap cuvettes) as a negative control and to monitor the efficiency of transfection through the number of green cells.…”

Antigen delivery systems for veterinary vaccine development

“…Vaccination of cattle with the EHV-1/BVDV recombinant resulted in BVDVspecific, neutralizing antibodies and reduction of viraemia levels and nasal virus shedding after a BVDV challenge infection. This shows that EHV-1 vectors are suitable for vaccination of cattle and may find application in cases where existing antibodies preclude use of live vector vaccines derived from bovine viruses, like the recombinant BHV-4 viruses reported recently which express BVDV glycoprotein E2 or BHV-1 gD [122,123]. Inoculation of the recombinants into rabbits or sheep induced neutralizing antibodies against the respective target pathogens.…”

Establishment of a Bovine Herpesvirus 4 based vector expressing a secreted form of the Bovine Viral Diarrhoea Virus structural glycoprotein E2 for immunization purposes

“…A major disadvantage of HSV-1 is its cytotoxicity for many cell types, including neurons, although genetic alterations have been made to reduce its cytotoxicity [ 37 ]. In contrast, we have previously shown that BoHV-4 is able to infect a wide variety of cell types, including neural cells and liver cells, without cytotoxicity [ 46 , 47 ]. These observations suggest that BoHV-4 might have the potential for use as a gene delivery vector for the nervous system and liver.…”