Vaccination of horses with a recombinant modified vaccinia Ankara virus (MVA) expressing African horse sickness (AHS) virus major capsid protein VP2 provides complete clinical protection against challenge

Abstract

HighlightsA recombinant modified Vaccinia Ankara virus expressing VP2 of African horse sickness virus serotype 9 was generated.Four horses were vaccinated on days 0 and 20. Three unvaccinated controls were used.Vaccinated and control horses were challenged intravenously with 107.4TCID50 of AHSV-9 on day 34 of the study.At challenge, vaccinates had virus neutralising antibodies but were negative for antibodies to AHSV-VP7.All vaccinates were completely protected against clinical signs of African horse sickness.

African Horse Sickness Caused by Genome Reassortment and Reversion to Virulence of Live, Attenuated Vaccine Viruses, South Africa, 2004–2014

“…Collectively, these findings have major implications for strategies to control AHS, both in AHS-endemic regions and during future incursions into currently AHSV-free areas. However, AHSV-LAV confers critical and effective protection for susceptible horses in AHS-endemic areas and, although potentially safer recombinant AHSV vaccines have proven effective in laboratory studies ( 37 , 38 ), these are not available commercially and they are yet to be evaluated in the field. Until alternative vaccines become commercially available, control of AHS will remain reliant on the use of AHSV-LAV coupled with the adoption of strategies to minimize the likelihood of natural dissemination of revertant and reassortant vaccine-derived viruses.…”

Immunoinformatics Prediction of Peptide-Based Vaccine Against African Horse Sickness Virus

“…Canarypox virus vectored (ALVAC®) vaccine expressing the (VP2) and (VP5) of (AHSV-4) was also studied against African horse sickness virus (AHSV) infection and it gave promising results [52]. More recently a pilot study has investigated the immunogenicity of recombinant Modified Vaccinia Ankara virus as a vector for the (AHSV-4): (VP2, VP7) and the non-structural protein (NS3) antigens, the results revealed the great potential for the (MVAVP2) in eliciting protective immunity against lethal (AHSV) infections [13,47].…”

“…(VP2) is the major protective antigen of (AHSV) that is responsible for the serotype formation. The majority of neutralizing epitopes are located on (VP2) which can be considered as the main target of immune response to the virus [11][12][13]17,18].…”

“…In addition, serotypes 5 and 9 are normally excluded from the (LAV) formulations as serotype 5 is difficult to attenuate and partially crossreacts with serotype 8 and serotype 9 partially cross-reacts with serotype 6 [1,9,11,12,[19][20][21]. A recent Approach applied is the recombinant technology that was used in the development of recombinant modified vaccinia ankara (MVA-VP2) vaccine which is highly protective against (AHSV), but the scale of it is limited to only two serotypes; (AHSV-4) and (AHSV-9) [5,9,10,13,17,18,22]. Therefore, it is important to consider alternative approaches for (AHSV) vaccine development.…”

Immunogenicity of plant‐produced African horse sickness virus‐like particles: implications for a novel vaccine

“…Due to raised international awareness and local dissatisfaction with the current vaccine, AHSV research has focussed in recent years on the development of recombinant vaccines based on selected antigenic AHSV proteins, particularly the outer capsid proteins VP2 and VP5. Baculovirus expression systems (Kanai et al ., ; Roy and Sutton, ) and poxvirus vectors (Alberca et al ., ; Calvo‐Pinilla et al ., , ; El Garch et al ., ; Guthrie et al ., ) have been used to produce vaccines that induce protective immunity against various AHSV antigens. Disadvantages inherent to these types of vaccines include firstly, that recombinant soluble antigens are generally poorly immunogenic and require potent adjuvants or repeated boost inoculations to enhance immunogenicity; secondly, that pre‐existing immunity against the viral vector may compromise vaccine efficacy.…”