Recombinant canarypox virus vector (ALVAC-AHSV) co-expressing synthetic genes encoding the outer capsid proteins (VP2 and VP5) of AHSV serotype 4 (AHSV-4) (Guthrie et al., 2009).
f. Immunization Route
Intramuscular injection (i.m.)
g.
Horse Response
Vaccination Protocol:
Two groups of four horses each (two males and two females) were inoculated intramuscularly with 10^7.1 or 10^6.4 TCID50, respectively, of ALVAC–AHSV in approximately 1 ml of diluent containing a Carbopol® 974P adjuvant (BF Goodrich) (Guthrie et al., 2009).
Vaccine Immune Response Type:
VO_0003057
Challenge Protocol:
All nine horses were challenged by intravenous inoculation of 105.5 TCID50 of AHSV-4 at 28 days after the second vaccination (week 8) (Guthrie et al., 2009).
Efficacy:
Post challenge, all horses remained healthy and showed no adverse effects after vaccination (Guthrie et al., 2009).
2. Plant Produced AHSV Serotype 5 VLPs Vaccine
a. Type:
Subunit vaccine
b. Status:
Research
c. Host Species for Licensed Use:
None
d. Antigen
Plant-produced AHSV-1/5 VLPs displaying VP2 and VP5 of serotype 5 as the outer shell lay- ered on the AHSV serotype 1 core (VP3/VP7) (O'Kennedy et al., 2022)
AHSV-1/5 VLPs were produced in N. benthamiana ðš«XT/FT. The AHSV virion is a triple layered particle formed by the outer capsids (VP2 and VP5), the middle layer (VP7), and the inner shell (VP3, subcore). D-(+)-Trehalose dihydrate (Sigma-Aldrich)(5 % m/v) was added to the TFF purified VLPs before filter sterilization with a 0.45 lM + 0.2 lM Sartopore 2 sterile capsule (Sartorius, 5441307H4) using a peristaltic pump. The appropriate filter sterilized VLPs were mixed with autoclaved adjuvant (5% Montanide GEL 01 PR, Seppic, France) immediately before vaccination. (O'Kennedy et al., 2022)
h. Immunization Route
Intraperitoneal injection (i.p.)
i. Description
A plant-produced AHSV-1/5 VLP (Chimaeric Virus-Like Particles) provides protection against AHSV-5 in IFNAR -/- mice. (O'Kennedy et al., 2022)
j.
Mouse Response
Vaccination Protocol:
Eight groups of IFNAR-/- mice (n = 3) were vaccinated intraperitoneally with 1 µg, 5 µg or 10 µg plant-produced VLPs or VP2. Five groups of mice (n = 6 for vaccinated; and n = 3 for control groups) were used in the challenge study. Mice in the challenge study, were prime boost vaccinated (days 0 and 14) with either 10 µg VLPs (group 1) or 10 µg VP2 (group 2) or PBS buffer (negative control, group 3) or BEI inactivated 5x10^4 PFU (positive control, group 4). (O'Kennedy et al., 2022)
Immune Response:
Mice vaccinated with a single dose of plant-produced chimaeric AHSV- 1/5 VLPs seroconverted at a 5 µg and 10 µg vaccine dose, within the first 14 days. The primary vaccination of AHSV-1/5 VLPs led to seroconversion of 1:40 (1.6 log10) and 1:28 (1.45 log10) when vaccinated with 5 and 10 lg AHSV-1/5 VLPs already on day 14, respectively. A booster vaccine was however necessary to elevate the neutralizing antibodies (nAbs) to 1:320 (2.5 log10) on day 28 for all VLP vaccine doses. Ten micrograms of soluble VP2 per mouse were required to equal this immune response after prime-boost vaccination. All the test antigens indicated a measure of CD4+/ CD8+ stimulation which is required to induce cell memory. Mice vaccinated with plant-produced AHSV-1/5 VLPs showed a larger increase in stimulation as compared to the OBP BEI inactivated vaccine as positive control and to a lesser extent for the soluble VP2 vaccinated mice. (O'Kennedy et al., 2022)
Challenge Protocol:
Groups 1–4 were challenged 28 days after the primary vaccine. Challenge with a dose containing 1.4 X 10^5 pfu of AHSV-5 per mouse on day 28 (14 days post booster immunization) was administered subcutaneously. (O'Kennedy et al., 2022)
Efficacy:
Protection against AHSV-5 conferred by both plant-produced adjuvanted VLPs and VP2 vaccines correlated strongly with SNTs determined during the immunogenicity study and mice (n = 6) of each group survived until day 25 post challenge when the study was terminated. The negative control group (PBS with adjuvant) succumbed within 8– 11 days after challenge. (O'Kennedy et al., 2022)
AHSV-5 VP2 was produced in N. benthamiana DXT/FT. D-(+)-Trehalose dihydrate (Sigma-Aldrich)(5 % m/v) was added to the IMAC purified VP2 antigens before filter sterilization with a 0.45 lM + 0.2 lM Sartopore 2 sterile capsule (Sartorius, 5441307H4) using a peristaltic pump. The appropriate filter sterilised VP2 antigens were mixed with autoclaved adjuvant (5% Montanide GEL 01 PR, Seppic, France) immediately before vaccination. (O'Kennedy et al., 2022)
g. Immunization Route
Intraperitoneal injection (i.p.)
h. Description
A plant produced AHSV Vaccine expressing VP2 antigen protects against AHSV-5 challenge in mice. (O'Kennedy et al., 2022)
i.
Mouse Response
Vaccination Protocol:
Eight groups of IFNAR-/- mice (n = 3) were vaccinated intraperitoneally with 1 µg, 5 µg or 10 µg plant-produced VLPs or VP2. Five groups of mice (n = 6 for vaccinated; and n = 3 for control groups) were used in the challenge study. Mice in the challenge study, were prime boost vaccinated (days 0 and 14) with either 10 µg VLPs (group 1) or 10 µg VP2 (group 2) or PBS buffer (negative control, group 3) or BEI inactivated 5x104 PFU (positive control, group 4). (O'Kennedy et al., 2022)
Immune Response:
Mice vaccinated with a single dose of plant-produced chimaeric AHSV- 1/5 VLPs seroconverted at a 5 µg and 10 µg vaccine dose, within the first 14 days. The primary vaccination of AHSV-1/5 VLPs led to seroconversion of 1:40 (1.6 log10) and 1:28 (1.45 log10) when vaccinated with 5 and 10 lg AHSV-1/5 VLPs already on day 14, respectively. A booster vaccine was however necessary to elevate the neutralizing antibodies (nAbs) to 1:320 (2.5 log10) on day 28 for all VLP vaccine doses. Ten micrograms of soluble VP2 per mouse were required to equal this immune response after prime-boost vaccination. All the test antigens indicated a measure of CD4+/ CD8+ stimulation which is required to induce cell memory. Mice vaccinated with plant-produced AHSV-1/5 VLPs showed a larger increase in stimulation as compared to the OBP BEI inactivated vaccine as positive control and to a lesser extent for the soluble VP2 vaccinated mice. (O'Kennedy et al., 2022)
Challenge Protocol:
Groups 1–4 were challenged 28 days after the primary vaccine. Challenge with a dose containing 1.4 X 105 pfu of AHSV-5 per mouse on day 28 (14 days post booster immunization) was administered subcutaneously. (O'Kennedy et al., 2022)
Efficacy:
Protection against AHSV-5 conferred by both plant-produced adjuvanted VLPs and VP2 vaccines correlated strongly with SNTs determined during the immunogenicity study and mice (n = 6) of each group survived until day 25 post challenge when the study was terminated. The negative control group (PBS with adjuvant) succumbed within 8– 11 days after challenge. (O'Kennedy et al., 2022)
Vaccination Protocol:
The mice were vaccinated by the intra-peritoneal route on days 0 and 28 with 10^7 pfu of MVA-VP2 per mouse (Castillo-Olivares et al., 2011).
Vaccine Immune Response Type:
VO_0000287
Challenge Protocol:
The mice were subsequently challenged on day 35 with 106 pfu of AHSV-4 (Castillo-Olivares et al., 2011).
Efficacy:
All of the MVA-VP2 vaccinated animals were also protected from clinical signs and were completely healthy until the end of the study period (Castillo-Olivares et al., 2011).
IV. References
1. Castillo-Olivares et al., 2011: Castillo-Olivares J, Calvo-Pinilla E, Casanova I, Bachanek-Bankowska K, Chiam R, Maan S, Nieto JM, Ortego J, Mertens PP. A modified vaccinia Ankara virus (MVA) vaccine expressing African horse sickness virus (AHSV) VP2 protects against AHSV challenge in an IFNAR -/- mouse model. PloS one. 2011; 6(1); e16503. [PubMed: 21298069].
2. de et al., 2015: de la Poza F, Marín-López A, Castillo-Olivares J, Calvo-Pinilla E, Ortego J. Identification of CD8 T cell epitopes in VP2 and NS1 proteins of African horse sickness virus in IFNAR(-/-) mice. Virus research. 2015; 210; 149-153. [PubMed: 26272673].
3. Guthrie et al., 2009: Guthrie AJ, Quan M, Lourens CW, Audonnet JC, Minke JM, Yao J, He L, Nordgren R, Gardner IA, Maclachlan NJ. Protective immunization of horses with a recombinant canarypox virus vectored vaccine co-expressing genes encoding the outer capsid proteins of African horse sickness virus. Vaccine. 2009; 27(33); 4434-4438. [PubMed: 19490959].
4. Manning et al., 2017: Manning NM, Bachanek-Bankowska K, Mertens PPC, Castillo-Olivares J. Vaccination with recombinant Modified Vaccinia Ankara (MVA) viruses expressing single African horse sickness virus VP2 antigens induced cross-reactive virus neutralising antibodies (VNAb) in horses when administered in combination. Vaccine. 2017; 35(44); 6024-6029. [PubMed: 28438410].
5. Rutkowska et al., 2011: Rutkowska DA, Meyer QC, Maree F, Vosloo W, Fick W, Huismans H. The use of soluble African horse sickness viral protein 7 as an antigen delivery and presentation system. Virus research. 2011; 156(1-2); 35-48. [PubMed: 21195731].
