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

Abstract

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.

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

“…The results demonstrated that the product did not induce any clinical signs or adverse reactions. The results of this study, in agreement with those published previously on cattle [17,31], suggested that in water buffalo, there is no risk of adverse reactions following the administration of the inactivated gE-deleted marker vaccine. Moreover, the outcomes of the present study demonstrate no clinical signs after immunization with the modified live gE-deleted marker vaccine.…”

“…Similar results were obtained in a study conducted by Montagnaro et al using a modified live gEdeleted marker vaccine in water buffalo [32]. Moreover, these results agree with the results of previous studies on cattle immunized with two inactivated gE-deleted marker vaccines [17]. In contrast, other studies described a low induction of NA against BoHV-1 after immunization with inactivated gE-deleted marker vaccines [33].…”

“…This study reported a low percentage of sera reactive to BoHV-1 (1.8%) and suggested that BuHV-1 could be the main circulating alphaherpesvirus infection in Mediterranean water buffaloes [12]. It is known that inactivated gE-deleted marker vaccines induce a high immune response in cattle [17,27], while no information is available regarding the induction of the immune response by these vaccines in the Bubalus bubalis against BoHV-1.…”

“…In cattle, the DIVA strategy is considered the first line of intervention for eradication programs in areas where IBR infection has a high prevalence. This strategy enables the differentiation of animals immunized with gE-deleted marker vaccines (gE-negative) from those infected with either the wild-type virus or immunized with traditional non-deleted marker vaccines (gE-positive) through diagnostic tests specific for gE of BoHV-1 [17,18,26,27].…”

“…The protective measures aimed at controlling BoHV-1 infection in cattle include the administration of live attenuated or inactivated vaccines. In addition, marker vaccines that lack one or more genes responsible for glycoprotein or enzyme synthesis have also been used [15][16][17][18]. The strategy of marker vaccination that differentiates the vaccinated animals is called Differentiating Infected from Vaccinated Animals (DIVA) [18].…”