Vaccination of calves against bovine herpesvirus-1: assessment of the protective value of eight vaccines

Assessment of BoAHV-1 Seronegative Latent Carrier by the Administration of Two Infectious Bovine Rhinotracheitis Live Marker Vaccines in Calves

Seronegative latent carriers (SNLCs) are animals that carry the virus without detectable antibodies and pose a risk for disease transmission and diagnostic challenges, suggesting the importance of consideration of marker vaccines in managing them. Therefore, in this study, we evaluated two modified live infectious bovine rhinotracheitis (IBR) marker vaccines (single and double deletions) for their ability to generate SNLC calves. These vaccines were administered to four groups (n = 3 in each group) of three-month-old calves in the presence or absence of passive immunity. Three hundred days after the first vaccination and after confirming the IBR seronegativity of all animals, dexamethasone was administered intravenously for five consecutive days. Only animals immunized with the modified live IBR marker vaccine (single deletion) in the absence of passive immunity exhibited a more enduring immune response than those vaccinated in the presence of passive immunity. Moreover, the administration of a modified live IBR marker vaccine (double deletion) to calves with passive immunity generated SNLC. These findings underscore the potential of live IBR marker vaccine (double-deletions) to aid serological diagnostic tools and develop vaccination protocols in achieving the desired immune response, particularly in the context of latent carrier status, offering valuable insights into optimizing vaccination strategies for effective IBR control.

The combination of vaccines and adjuvants to prevent the occurrence of high incidence of infectious diseases in bovine

As the global population grows, the demand for beef and dairy products is also increasing. The cattle industry is facing tremendous pressures and challenges. The expanding cattle industry has led to an increased risk of disease in cattle. These diseases not only cause economic losses but also pose threats to public health and safety. Hence, ensuring the health of cattle is crucial. Vaccination is one of the most economical and effective methods of preventing bovine infectious diseases. However, there are fewer comprehensive reviews of bovine vaccines available. In addition, the variable nature of bovine infectious diseases will result in weakened or even ineffective immune protection from existing vaccines. This shows that it is crucial to improve overall awareness of bovine vaccines. Adjuvants, which are crucial constituents of vaccines, have a significant role in enhancing vaccine response. This review aims to present the latest advances in bovine vaccines mainly including types of bovine vaccines, current status of development of commonly used vaccines, and vaccine adjuvants. In addition, this review highlights the main challenges and outstanding problems of bovine vaccines and adjuvants in the field of research and applications. This review provides a theoretical and practical basis for the eradication of global bovine infectious diseases.

Evaluation of an Immunization Protocol Using Bovine Alphaherpesvirus 1 gE-Deleted Marker Vaccines against Bubaline Alphaherpesvirus 1 in Water Buffaloes

European regulations on the control of infectious diseases provide measures to control Bovine alphaherpesvirus 1 (BoHV-1) infection in both cattle and buffalo. Owing to the reported serological cross-reactivity between BoHV-1 and Bubaline alphaherpesvirus 1 (BuHV-1), we hypothesized a new immunization protocol using BoHV-1 gE-deleted marker vaccines could protect water buffalo against BuHV-1. Five water buffaloes devoid of BoHV-1/BuHV-1-neutralizing antibodies were immunized with two commercial BoHV-1 gE-deleted marker vaccines at 0, 30, 210, and 240 post-vaccination days (PVDs). Five additional water buffaloes were used as controls. At 270 PVD (0 post-challenge days (PCDs), all animals were challenged intranasally with wild-type (wt) BuHV-1. The vaccinated animals produced humoral immunity (HI) as early as PVD 30 whereas, in control animals, antibodies were detected on PCD 10. After challenge infection, HI significantly increased in vaccinated animals compared to that in controls. Real-time PCR for gB revealed viral shedding in vaccinated animals from PCDs 2 to 10. In contrast, positive results were observed from PCDs 2 to 15 in the unvaccinated control group. Although the findings indicated the possible protection capabilities of the tested protocol, these findings did not support its protective roles in water buffaloes against wt-BuHV-1.

Subunit vaccine based on glycoprotein B protects pattern animal guinea pigs from tissue damage caused by infectious bovine rhinotracheitis virus

Infectious bovine rhinotracheitis (IBR) is caused by Bovine herpesvirus type 1 (BoHV-1), which seriously threatens the global cattle industry. Only vaccination to improve immunity is the most direct and effective means to prevent IBR. Attempts are being made to use subunit vaccines, deleted or recombinant viral vaccines to reduce or eradicate IBR. For investigating the immunological characteristics of glycoprotein B subunit vaccine in pattern animal guinea pigs, the partial glycoprotein B (gB) of BoHV-1 with dominant antigenic characteristic was selected. A recombinant prokaryotic expression vector pET-32a-gB with the truncated gB gene was constructed, expressed, identified and the purified proteins were used to immunize guinea pigs. The immune effect of the subunit vaccine was assessed by monitoring clinical symptoms, viral load, antibody secretion, and histopathological changes. The results indicated that guinea pigs immunized with the gB subunit vaccine produced high levels of anti-gB antibodies and virus-neutralizing antibodies. The gB subunit vaccine significantly reduced viral shedding and lung tissue damage after IBRV challenge. The animals inoculated the gB subunit vaccine also had less virus reactivation. Its protective effect on viral shedding and tissue damage was similar to that of inactivated BoHV-1 vaccine. This work is a proof-of-concept study of subunit vaccine-induced protection against BoHV-1. And it is expected to be a candidate vaccine for the prevention of IBR.

Assessment of Different Infectious Bovine Rhinotracheitis Marker Vaccines in Calves

Three commercially available infectious bovine rhinotracheitis (IBR) live marker vaccines were evaluated for their ability to provide clinical protection to vaccinated calves against wild-type (wt) Bovine alphaherpesvirus-1 (BoHV-1) challenge and their possible effect on wt BoHV-1 latency reactivation following the challenge. On 35 post-vaccination days (PVDs), all animals were challenged with wt BoHV-1. Only the calves in the control group developed severe forms of IBR. The reactivation of latent BoHV-1 was induced by dexamethasone (DMS) treatment on 28 post-challenge days (PCDs). All animals showed IBR clinical signs on three post-DMS treatment days (PDTDs). On PVD 14, all vaccinated animals developed neutralizing antibodies (NAs), whereas in control animals, the NAs appeared post-challenge. The positivity for glycoprotein-B (gB) was detected using real-time polymerase chain reactions in all animals from PCDs 1 to 7. In contrast, the gB-positivity was observed in the immunized calves from PDTDs 3 to 10. Positive expression of gD and gE was observed in nasal swabs of all calves on PDTD 7. These findings suggested that the IBR marker vaccines evaluated in this study protected against wt BoHV-1-induced disease but not against wt BoHV-1-induced latency reactivation, indicating the necessity of developing new products to protect animals from wt BoHV-1-induced latency.

Recombinant Bovine Herpesvirus Type I Expressing the Bovine Viral Diarrhea Virus E2 Protein Could Effectively Prevent Infection by Two Viruses

Bovine respiratory disease complex (BRDC) is a comprehensive disease in cattle caused by various viral and bacterial infections. Among them, bovine herpesvirus type I (BoHV−1) and bovine viral diarrhea virus (BVDV) play important roles and have caused huge financial losses for the cattle industry worldwide. At present, vaccines against BRDC include trivalent attenuated BoHV−1, BVDV−1, and BVDV−2 live vaccines, BoHV−1 live attenuated vaccines, and BoHV−1/BVDV bivalent live attenuated vaccines, which have limitations in terms of their safety and efficacy. To solve these problems, we optimized the codon of the BVDV−1 E2 gene, added the signal peptide sequence of the BoHV−1 gD gene, expressed double BVDV−1 E2 glycoproteins in tandem at the BoHV−1 gE gene site, and constructed a BoHV−1 genetics-engineered vectored vaccine with gE gene deletion, named BoHV−1 gE/E2−Linker−E2⁺ and BoHV−1 ΔgE. This study compared the protective effects in BoHV−1, BoHV−1 ΔgE, BoHV−1 gE/E2−Linker−E2⁺, and BVDV−1 inactivated antigen immunized guinea pigs and calves. The results showed that BoHV−1 gE/E2−Linker−E2⁺ could successfully induce guinea pigs and calves to produce specific neutralizing antibodies against BVDV−1. In addition, after BoHV−1 and BVDV−1 challenges, BoHV−1 gE/E2−Linker−E2⁺ can produce a specific neutralizing antibody response against BoHV−1 and BVDV−1 infections. Calves immunized with this type of virus can be distinguished as either vaccinated animals (gE^-) or naturally infected animals (gE⁺). In summary, our data suggest that BoHV−1 gE/E2−Linker−E2⁺ and BoHV−1 ΔgE have great potential to prevent BVDV−1 or BoHV−1 infection.

Challenges in Veterinary Vaccine Development

Animals provide food and clothing in addition to other value-added products. Changes in diet and lifestyle have increased the consumption and the use of animal products. Infectious diseases in animals are a major threat to global animal health and its welfare; their effective control is crucial for agronomic health, for safeguarding food security and also alleviating rural poverty. Development of vaccines has led to increased production of healthy poultry, livestock, and fish. Animal production increases have alleviated food insecurity. In addition, development of effective vaccines has led to healthier companion animals. However, challenges remain including climate change that has led to enhancement in vectors and pathogens that may lead to emergent diseases in animals. Preventing transmission of emerging infectious diseases at the animal-human interface is critically important for protecting the world population from epizootics and pandemics. Hence, there is a need to develop new vaccines to prevent diseases in animals. This review describes the broad challenges to be considered in the development of vaccines for animals.

TLR activation, immune response and viral protection elicited in cattle by a commercial vaccine against Bovine Herpesvirus-1

The innate and acquired immune response induced by a commercial inactivated vaccine against Bovine Herpesvirus-1 (BoHV-1) and protection conferred against the virus were analyzed in cattle. Vaccination induced high levels of BoHV-1 antibodies at 30, 60, and 90 days post-vaccination (dpv). IgG1 and IgG2 isotypes were detected at 90 dpv, as well as virus-neutralizing antibodies. An increase of anti-BoHV-1 IgG1 in nasal swabs was detected 6 days post-challenge in vaccinated animals. After viral challenge, lower virus excretion and lower clinical score were observed in vaccinated as compared to unvaccinated animals, as well as BoHV-1-specific proliferation of lymphocytes and production of IFNγ, TNFα, and IL-4. Downregulation of the expression of endosome Toll-like receptors 8-9 was detected after booster vaccination. This is the first thorough study of the immunity generated by a commercial vaccine against BoHV-1 in cattle.

Evaluation of Safety and Efficacy of an Inactivated Marker Vaccine against Bovine alphaherpesvirus 1 (BoHV-1) in Water Buffalo (Bubalus bubalis)

Recent studies have explored the seropositivity of Bovine alphaherpesvirus 1 (BoHV-1) in water buffaloes, suggesting the urgency for developing strategies to eradicate the virus involving both cattle and water buffaloes. However, in Europe, the glycoprotein E (gE) deleted marker vaccines against BoHV-1 are commercially available only for the cattle industry. This study, for the first time, evaluated the safety and efficacy of a commercial inactivated gE-deleted marker vaccine in water buffalo. Five animals devoid of BoHV-1-neutralizing antibodies were vaccinated via intramuscular route. Five additional animals served as an unvaccinated control group. Sixty days after the first immunization, all animals were experimentally infected with a virulent BoHV-1via intranasal route. A detectable BoHV-1-humoral immune response was observed in the vaccinated group on post-vaccination day 30, whereas the antibodies appeared on post-challenge day 10 in the control group. Moreover, the vaccinated animals neither show viral shedding nor clinical signs compared to the control upon challenge. However, post-challenge, the BoHV-1-specific humoral and cell-mediated immune responses were significantly more increased in vaccinated animals than the control animals. Overall, the present study provides evidence of both the safety and efficacy of an inactivated gE-deleted marker vaccine against BoHV-1 in water buffaloes.

Evaluation of Passive Immunity Induced by Immunisation Using Two Inactivated gE-deleted Marker Vaccines against Infectious Bovine Rhinotracheitis (IBR) in Calves

Different types of vaccines against Infectious Bovine Rhinotracheitis (IBR) are commercially available. Among these, inactivated glycoprotein E (gE)-deleted marker vaccines are commonly used, but their ability to induce passive immunity is poorly known. Here, we evaluated the passive immunity transferred from dams immunised with commercial inactivated gE-deleted marker vaccines to calves. We vaccinated 12 pregnant cattle devoid of neutralising antibodies against Bovine alphaherpesvirus 1 (BoHV-1) and divided them into two groups with 6 animals each. Both groups were injected with a different inactivated gE-deleted marker vaccine administrated via intranasal or intramuscular routes. An additional 6 pregnant cattle served as the unvaccinated control group. After calving, the number of animals in each group was increased by the newborn calves. In the dams, the humoral immune response was evaluated before calving and, subsequently, at different times until post-calving day 180 (PCD180). In addition, the antibodies in colostrum, milk, and in serum samples from newborn calves were evaluated at different times until PCD180. The results indicated that inactivated glycoprotein E (gE)-deleted marker vaccines are safe and produce a good humoral immune response in pregnant cattle until calving and PCD180. Moreover, results showed that, in calf serum, passive immunity persists until PCD180.

Antibody Responses to Bovine Alphaherpesvirus 1 (BoHV-1) in Passively Immunized Calves

To date, in countries where infectious bovine rhinotracheitis (IBR) is widespread, its control is associated with deleted marker vaccines. These products lack one or more genes responsible for the synthesis of glycoproteins or enzymes. In Europe, the most widely used marker vaccine is one in which glycoprotein E (gE-) is deleted, and it is marketed in a killed or modified-live form. Using this type of immunization, it is possible to differentiate vaccinated animals (gE-) from those infected or injected with non-deleted (gE+) products using diagnostic tests specific for gE. The disadvantage of using modified-live gE-products is that they may remain latent in immunized animals and be reactivated or excreted following an immunosuppressive stimulus. For this reason, in the last few years, a new marker vaccine became commercially available containing a double deletion related to genes coding for gE and the synthesis of the thymidine-kinase (tk) enzyme, the latter being associated with the reduction of the neurotropism, latency, and reactivation of the vaccine virus. Intramuscularly and intranasally administered marker products induce a humoral immune response; however, the mother-to-calf antibody kinetics after vaccination with marker vaccines is poorly understood. This review discusses several published articles on this topic.

Evaluation of BHV-1 antibody titer in a cattle herd against different BHV-1 strains

Although modified-live multivalent vaccines, such as PregGuard GOLD and Bovi-Shield Gold, have been used routinely in both beef and dairy cattle in the US, abortion and respiratory diseases still occasionally occur following vaccination. To determine whether the antibody induced by the multivalent vaccine can recognize BHV-1 isolates from aborted animals, BHV-1 antibody titer was evaluated with two isolates from abortion cases and two vaccine BHV-1 viruses. Cattle serum was collected from a dairy herd that was vaccinated annually with Bovi-Shield Gold 5 vaccine. Among the 28 cattle tested, no statistical significant difference in serum neutralization titer was observed when test virus was either vaccine virus or clinical isolates. It suggests that the BHV-1 antibody from the vaccinated cattle can recognize both the vaccine virus and clinical isolates. However, it is noticed that cows at 5 years old or older had a significantly lower BHV-1 antibody titer on average than the average of SN titer in 3 year-old cows. Similarly, cows at 5 years or older had a significantly lower BVDV antibody titer than cows at about 2 years of age. In addition, cattle vaccinated within 0-2 months had a significantly higher BHV-1 titer than those that received vaccination 6 months or greater prior to titer measurement. In contrast, cattle that received a vaccination 6 months prior had a significantly higher anti-BVDV antibody titer than those vaccinated within 1-2 months. The BVDV antibody titers remained relatively unchanged between 6 months and 1 year post-vaccination. Our study suggests little antigenic variation exists between BHV-1 disease isolates and BHV-1 of the multivalent vaccines. In addition, BHV-1 antibody titer is relatively lower at 6 months post vaccination in those tested animals. However, the BVDV antibody titer remained relatively high after 6 months from time of vaccination.

Inclusion of the bovine neutrophil beta-defensin 3 with glycoprotein D of bovine herpesvirus 1 in a DNA vaccine modulates immune responses of mice and cattle

Bovine herpesvirus 1 (BoHV-1) causes recurrent respiratory and genital infections in cattle and predisposes them to lethal secondary infections. While modified live and killed BoHV-1 vaccines exist, these are not without problems. Development of an effective DNA vaccine for BoHV-1 has the potential to address these issues. As a strategy to enhance DNA vaccine immunity, a plasmid encoding the bovine neutrophil beta-defensin 3 (BNBD3) as a fusion with truncated glycoprotein D (tgD) and a mix of two plasmids encoding BNBD3 and tgD were tested in mice and cattle. In mice, coadministration of BNBD3 on the separate plasmid enhanced the tgD-induced gamma interferon (IFN-γ) response but not the antibody response. BNBD3 fused to tgD did not affect the antibody levels or the number of IFN-γ-secreting cells but increased the induction of tgD-specific cytotoxic T lymphocytes (CTLs). In cattle, the addition of BNBD3 as a fusion construct also modified the immune response. While the IgG and virus-neutralizing antibody levels were not affected, the number of IFN-γ-secreting cells was increased after BoHV-1 challenge, specifically the CD8(+) IFN-γ(+) T cells, including CD8(+) IFN-γ(+) CD25(+) CTLs. While reduced virus shedding, rectal temperature, and weight loss were observed, the level of protection was comparable to that observed in pMASIA-tgD-vaccinated animals. These data show that coadministration of BNBD3 with a protective antigen as a fusion in a DNA vaccine strengthened the Th1 bias and increased cell-mediated immune responses but did not enhance protection from BoHV-1 infection.

Bovine herpes virus infections in cattle

Bovine herpes virus 1 (BHV-1) is primarily associated with clinical syndromes such as rhinotracheitis, pustular vulvovaginitis and balanoposthitis, abortion, infertility, conjunctivitis and encephalitis in bovine species. The main sources of infection are the nasal exudates and the respiratory droplets, genital secretions, semen, fetal fluids and tissues. The BHV-1 virus can become latent following a primary infection with a field isolate or vaccination with an attenuated strain. The viral genomic DNA has been demonstrated in the sensory ganglia of the trigeminal nerve in infectious bovine rhinotracheitis (IBR) and in sacral spinal ganglia in pustular vulvovaginitis and balanoposthitis cases. BHV-1 infections can be diagnosed by detection of virus or virus components and antibody by serological tests or by detection of genomic DNA by polymerase chain reaction (PCR), nucleic acid hybridization and sequencing. Inactivated vaccines and modified live virus vaccines are used for prevention of BHV-1 infections in cattle; subunit vaccines and marker vaccines are under investigation.

Viral diseases of the ruminant nervous system

This article presents the etiology, epidemiology, clinical features,and diagnosis of the primary viral neurologic diseases observed in ruminants. In general, these viral neurologic diseases are uncommon but often fatal. Rabies virus is perhaps the most important cause of encephalitis in cattle because of the public health implications. Other viral encephalitis diseases in ruminants include bovine herpesvirus encephalomyelitis, pseudorabies, malignant catarrhal fever, ovine and caprine lentiviral encephalitis, West Nile virus encephalitis, Borna disease, paramyxoviral sporadic bovine encephalomyelitis,and ovine encephalomyelitis (louping-ill).

Immunization against bovine herpesvirus-1 infection. Preliminary tests in calves with a DNA vaccine

A bovine herpesvirus-1 (BHV-1) vaccine expressing glycoprotein D, the form with the transmembrane anchor removed, was evaluated for inducing immunity in calves. The plasmid encoding gD of BHV-1 was injected three times to nine calves, using three animals for each of the following routes: intramuscularly (i.m.), intradermally (i.d.), or intranasally (i.n.). Three additional calves were given the plasmid vector only and served as unvaccinated controls. When calves were subjected to challenge infection with BHV-1, all vaccinated calves as well as the controls developed a typical severe form of infectious bovine rhinotracheitis. However, compared to the controls, the vaccinated calves showed earlier clearance of challenge virus. Moreover, the calves given the vaccine i.m. developed neutralizing antibody to BHV-1 between 21 and 42 days following the first injection of vaccine, whereas in calves vaccinated either i.d. or i.n., as well as the controls, antibody first appeared in their sera 14 days post-challenge infection.

A study on latency in calves by five vaccines against bovine herpesvirus-1 infection

Four bovine herpesvirus-1 (BHV-1) commercial vaccines, three of which (vaccines B, D, E) were modified live vaccines (MLV) and one (vaccine A) identified as a live strain of BHV-1 gE negative, were used for vaccination of calves, using three calves for each vaccine. Three months after vaccination calves were subjected to dexamethasone (DMS) treatment following which virus was recovered from calves inoculated with vaccine B and from those given vaccine D. No virus reactivation was obtained in calves, which received vaccines A or E. The DNA extracted from the two reactivated viruses was subjected to restriction endonuclease analysis. The restriction pattern of the isolate obtained from calves vaccinated with vaccine D differs significantly from that of the original vaccine, whereas the reactivated virus from calves given vaccine B conserved the general pattern of the original vaccine strain. For each reactivated virus in this experiment (B and D) as well as for the isolate obtained from calves vaccinated with a further MLV (vaccine C) in a previous trial, three calves were inoculated. No clinical signs of disease were detected in any of the inoculated calves during the observation period. When the nine calves were exposed 40 days later to challenge infection with virulent BHV-1, they remained healthy and no virus was isolated from their nasal swabbings. These results indicate that some BHV-1 vaccines considered in the project can establish latency in the vaccinated calves, however, the latency does not appear to interfere with the original properties of the vaccines in terms of safety and efficacy.