United States of America, As Represented by the Secretary of Agriculture

Marla J Koster

Marvin J Grubman

Fayna C Diaz-San Segundo

Teresa B De Los Santos

James J Zhu

Jarasvech Chinsangaram

Mauro P Moraes

Mauro Moraes

A member of the bovine type III IFN family, boIFN-&#x3bb;3, was identified and characterized. We expressed boIFN-&#x3bb;3 using a recombinant replication defective human adenovirus type 5 (Ad5) and demonstrated antiviral activity against foot-and-mouth disease virus (FMDV) and vesicular stomatitis virus (VSV) in bovine cells in vitro. Cattle were inoculated with Ad5-boIFN-&#x3bb;3 followed by intradermolingual or aerosol FMDV challenge. Results demonstrated that the type III IFN family is conserved in bovines and that treatment of cattle with boIFN-&#x3bb;3 alone or in combination with IFN-&#x3b1; is able to confer delayed and reduced severity of FMD. Furthermore inoculation with Ad5-boIFN-&#x3bb;3 alone conferred full protection against aerosol challenge for at least 7 days after administration suggesting that type III IFN used in combination with FMD vaccines could fill one of the current gaps in emergency vaccination against FMDV.

Antiviral activity of bovine type III interferon against foot-and-mouth disease virus

Previously we have identified a conserved domain (SAP, for SAF-A/B, Acinus, and PIAS) in the foot-and-mouth disease virus (FMDV) leader (L) protein coding region that is required for proper sub-cellular localization and function. Mutation of isoleucine 55 and leucine 58 to alanine (I55A, L58A) within the SAP domain resulted in a viable virus that displayed a mild attenuated phenotype in cell culture, along with altered sub-cellular distribution of L and failure to induce degradation of the transcription factor nuclear factor kappa-B. Here we report that inoculation of swine and cattle with this mutant virus results in the absence of clinical disease, the induction of a significant FMDV-specific neutralizing antibody response, and protection against subsequent homologous virus challenge. Remarkably, swine vaccinated with SAP mutant virus are protected against wild type virus challenge as early as two days post-vaccination suggesting that a strong innate as well as adaptive immunity is elicited. This variant could serve as the basis for construction of a live-attenuated FMD vaccine candidate.

Recombinant live attenuated foot-and-mouth disease (FMD) vaccine containing mutations in the L protein coding region

Early protection of susceptible animals against foot and mouth disease (FMD) may be achieved by inoculating the animals with a vaccine comprising an interferon DNA sequence. One day after inoculation, animals have been found protected from challenge with virulent foot and mouth disease virus. Co-administration with an effective foot and mouth disease virus vaccine provides protection prior to the development of specific immunity, a feature especially desireable during a FMD outbreak.

Foot and mouth disease virus vaccine comprising interferons

Previously, we showed that type I interferon (alpha/beta interferon [IFN-&#x3b1;/&#x3b2;]) can inhibit foot-and-mouth disease virus (FMDV) replication in cell culture, and swine inoculated with 10PFU of human adenovirus type 5 expressing porcine IFN-&#x3b1; (Ad5-pIFN-&#x3b1;) were protected when challenged 1 day later. In this study, we found that type II pIFN (pIFN-&#x3b3;) also has antiviral activity against FMDV in cell culture and that, in combination with pIFN-&#x3b1;, it has a synergistic antiviral effect. We also observed that while each IFN alone induced a number of IFN-stimulated genes (ISGs), the combination resulted in a synergistic induction of some ISGs. To extend these studies to susceptible animals, we inoculated groups of swine with a control Ad5, 10PFU of Ad5-pIFN-&#x3b1;, low- or high-dose Ad5-pIFN-&#x3b3;, or a combination of Ad5-pIFN-&#x3b1; and low- or high-dose Ad5-pIFN-&#x3b3; and challenged all groups with FMDV 1 day later. The control group and the groups inoculated with either Ad5-pIFN-&#x3b1; or a low dose of Ad5-pIFN-&#x3b3; developed clinical disease and viremia. However, the group that received the combination of both Ad5-IFNs with the low dose of Ad5-pIFN-&#x3b3; was completely protected from challenge and had no viremia. Similarly the groups inoculated with the combination of Ad5s with the higher dose of Ad5-pIFN-&#x3b3; or with only high-dose Ad5-pIFN-&#x3b3; were protected. The protected animals did not develop antibodies against viral nonstructural (NS) proteins, while all infected animals were NS protein seropositive. No antiviral activity or significant levels of IFNs were detected in the protected groups, but there was an induction of some ISGs. The results indicate that the combination of type I and II IFNs act synergistically to inhibit FMDV replication in vitro and in vivo.

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Cutchogue, NY, United States of America

Marla J Koster