Protective efficacy of a single immunization with capripoxvirus-vectored recombinant peste des petits ruminants vaccines in presence of pre-existing immunity.
Sheeppox, goatpox and peste des petits ruminants (PPR) are highly contagious ruminant diseases widely distributed in Africa, the Middle East and Asia. Capripoxvirus (CPV)-vectored recombinant PPR vaccines (rCPV-PPR vaccines), which have been developed and shown to protect against both Capripox (CP) and PPR, would be critical tools in the control of these important diseases. In most parts of the world, these disease distributions overlap each other leaving concerns about the potential impact that pre-existing immunity against either disease may have on the protective efficacy of these bivalent rCPV-PPR vaccines. Currently, this question has not been indisputably addressed. Therefore, we undertook this study, under experimental conditions designed for the context of mass vaccination campaigns of small ruminants, using the two CPV recombinants (Kenya sheep-1 (KS-1) strain-based constructs) developed previously in our laboratory. Pre-existing immunity was first induced by immunization either with an attenuated CPV vaccine strain (KS-1) or the attenuated PPRV vaccine strain (Nigeria 75/1) and animals were thereafter inoculated once subcutaneously with a mixture of CPV recombinants expressing either the hemagglutinin (H) or the fusion (F) protein gene of PPRV (10(3) TCID50/animal of each). Finally, these animals were challenged with a virulent CPV strain followed by a virulent PPRV strain 3 weeks later. Our study demonstrated full protection against CP for vaccinated animals with prior exposure to PPRV and a partial protection against PPR for vaccinated animals with prior exposure to CPV. The latter animals exhibited a mild clinical form of PPR and did not show any post-challenge anamnestic neutralizing antibody response against PPRV. The implications of these results are discussed herein and suggestions made for future research regarding the development of CPV-vectored vaccines.
CIRAD, UMR CMAEE, F-34398 Montpellier, France; INRA, UMR1309 CMAEE, F-34398 Montpellier, France. Electronic address: philippe.caufour@cirad.fr.
Philippe
P
Caufour
National Animal health Diagnosis and Investigation Center (NAHDIC), P.O. Box 04, Sebeta, Ethiopia.
Tesfaye
T
Rufael
Animal Production and Health Laboratory, FAO/IAEA Agriculture & Biotechnology Laboratory, IAEA Laboratories, International Atomic Energy Agency, Wagramer Strasse 5, P.O. Box 100, A-1400 Vienna, Austria.
Charles Euloge
CE
Lamien
CIRAD, UMR CMAEE, F-34398 Montpellier, France; INRA, UMR1309 CMAEE, F-34398 Montpellier, France.
Renaud
R
Lancelot
National Animal health Diagnosis and Investigation Center (NAHDIC), P.O. Box 04, Sebeta, Ethiopia.
Menbere
M
Kidane
National Animal health Diagnosis and Investigation Center (NAHDIC), P.O. Box 04, Sebeta, Ethiopia.
Dino
D
Awel
National Animal health Diagnosis and Investigation Center (NAHDIC), P.O. Box 04, Sebeta, Ethiopia.
Tefera
T
Sertse
CIRAD, UMR CMAEE, F-34398 Montpellier, France; INRA, UMR1309 CMAEE, F-34398 Montpellier, France.
Olivier
O
Kwiatek
CIRAD, UMR CMAEE, F-34398 Montpellier, France; INRA, UMR1309 CMAEE, F-34398 Montpellier, France.
Geneviève
G
Libeau
National Animal health Diagnosis and Investigation Center (NAHDIC), P.O. Box 04, Sebeta, Ethiopia.
Mesfin
M
Sahle
Animal Production and Health Laboratory, FAO/IAEA Agriculture & Biotechnology Laboratory, IAEA Laboratories, International Atomic Energy Agency, Wagramer Strasse 5, P.O. Box 100, A-1400 Vienna, Austria.
Adama
A
Diallo
INRA, UMR1309 CMAEE, F-34398 Montpellier, France; CIRAD, UMR CMAEE, F-97170 Petit-Bourg, Guadeloupe, France.
Emmanuel
E
Albina
D000818:Animals; D000914:Antibodies, Viral / Q000097:blood; D018151:Capripoxvirus / Q000276:immunology*; D015511:Goat Diseases / Q000517:prevention & control*; D006041:Goats; D008297:Male; D009500:Neutralization Tests; D029021:Peste-des-Petits-Ruminants / Q000517:prevention & control*; D018107:Peste-des-petits-ruminants virus; D014614:Vaccines, Synthetic / Q000276:immunology; D014765:Viral Vaccines / Q000276:immunology*
D000914:Antibodies, Viral; D014614:Vaccines, Synthetic; D014765:Viral Vaccines
Capripoxvirus; Peste des petits ruminants; Pre-existing immunity; Recombinant viral vector; Vaccine efficacy