Vaccination of sheep with Maedi-visna virus gag gene and protein, beneficial or harmful?
In spite of intense efforts no vaccine is yet available that protects against lentiviral infections. Sheep were immunised eight times over a period of 2.5 years with the maedi-visna (MVV) gag gene on two different vectors, 2 sheep with VR1012-gag-CTE and 2 sheep with pcDNA3.1-gag-CTE. All sheep responded to some of the mature MVV Gag proteins in Western blot (WB). Three of them responded to the virus in lymphocyte proliferation test. The sheep received a boost with recombinant Gag protein resulting in elevated antibody response. However, when they were challenged intratracheally with MVV they all became immediately infected as judged by a strong rise in antibody titer and virus isolation from blood. It is therefore clear that the vaccination gave no protection. It is even possible that it facilitated infectivity since virus was isolated earlier from all the vaccinated sheep than from any of the unvaccinated sheep infected in the same way with the same dose.
Torsteinsdóttir
Sigurbjörg
S
Institute for Experimental Pathology, University of Iceland, Keldur v/Vesturlandsveg, IS-112 Reykjavík, Iceland. sibbath@hi.is
Carlsdóttir
Helga María
HM
Svansson
Vilhjálmur
V
Matthíasdóttir
Sigrídur
S
Martin
Agnes Helga
AH
Pétursson
Gudmundur
G
D000818:Animals; D000914:Antibodies, Viral / Q000276:immunology; D002460:Cell Line; D049109:Cell Proliferation; D002478:Cells, Cultured; D002522:Chlorocebus aethiops; D004279:DNA, Viral / Q000235:genetics / Q000276:immunology; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D015683:Gene Products, gag / Q000235:genetics / Q000276:immunology* / Q000378:metabolism*; D007114:Immunization; D008214:Lymphocytes / Q000166:cytology / Q000276:immunology; D012756:Sheep / Q000276:immunology*; D013997:Time Factors; D014611:Vaccination / Q000009:adverse effects*; D014790:Visna-maedi virus / Q000235:genetics / Q000276:immunology* / Q000302:isolation & purification / Q000378:metabolism*
D000914:Antibodies, Viral; D004279:DNA, Viral; D015683:Gene Products, gag