The Development of Classical Swine Fever Marker Vaccines in Recent Years

Abstract

Classical swine fever (CSF) is a severe disease that has caused serious economic losses for the global pig industry and is widely prevalent worldwide. In recent decades, CSF has been effectively controlled through compulsory vaccination with a live CSF vaccine (C strain). It has been successfully eradicated in some countries or regions. However, the re-emergence of CSF in Japan and Romania, where it had been eradicated, has brought increased attention to the disease. Because the traditional C-strain vaccine cannot distinguish between vaccinated and infected animals (DIVA), this makes it difficult to fight CSF. The emergence of marker vaccines is considered to be an effective strategy for the decontamination of CSF. This paper summarizes the progress of the new CSF marker vaccine and provides a detailed overview of the vaccine design ideas and immunization effects. It also provides a methodology for the development of a new generation of vaccines for CSF and vaccine development for other significant epidemics.

Development of Porcine Monoclonal Antibodies with In Vitro Neutralizing Activity against Classical Swine Fever Virus from C-Strain E2-Specific Single B Cells

“…The immunized antigen should have the ability to induce strong immune responses, especially nAb responses. The glycoprotein E2 of CSFV exposed on the outer surface is responsible for inducing nAbs and eliciting protective immunity against CSFV [4,[8][9][10][11][12][13]. Thus, we administered three doses of CE2 based vaccine to induce a high proportion of nAb-secreting B cells in peripheral blood of immunized pigs.…”

“…To date, alternative DIVA vaccine strategies based on CSFV envelope glycoprotein E2 have been developed. These include CSFV E2 subunit vaccines [8][9][10][11][12][13] and live chimeric virus vaccine made by replacing the E2 of the closely related bovine viral diarrhea virus with the E2 of CSFV [14][15][16]. Their DIVA concept is based on the fact that field-virus-infected animals can raise antibodies to an additional antigen (such as E rns protein), while vaccinated animals only develop a CSFV E2-specific antibody response.…”

“…Unfortunately, the E2-substituted chimeric virus vaccine (Suvaxyn CSF Marker) is only approved by the EU for emergency vaccination within restricted control. E2 subunit vaccines can effectively induce CSF protection, but they induced shorter immunity compared to the live attenuated vaccine, thus two or more doses are required followed by single-dose re-vaccination every six months [8][9][10][11][12]. These limitations indicate a need for development of new and better vaccine platforms for CSF control and prevention.…”

Review detection of Newcastle disease virus

“…But the best way is to immunize with an NDV-marked vaccine or a gene-deleted vaccine. For example, the swine fever rabbit attenuated vaccine is modified so that it lacks a certain gene (such as E0) or a certain segment (such as E2), but its immunogenicity does not change ( 90 , 91 ). Using the protein expressed by the deleted gene as a diagnostic antigen can distinguish the antibodies produced by vaccinated pigs and naturally infected pigs.…”

Generation and Efficacy of Two Chimeric Viruses Derived from GPE− Vaccine Strain as Classical Swine Fever Vaccine Candidates

“…Extensive vaccination using live attenuated vaccines has been implemented and widely applied in several countries as a mandatory CSF control program, along with other biosafety approaches [ 9 ]. Although the advantage of the above vaccines is to provide complete protection against CSF, a drawback of vaccines is the lack of an immunological marker for differentiating infected from vaccinated animals (DIVA), making proof of CSF eradication difficult and inhibiting international pig trade [ 10 , 11 ]. In this scenario, the ideal vaccine can be engineered by combining live attenuated vaccines with marker properties [ 10 , 12 ].…”