Correlation between the induction of Th1 cytokines by an attenuated equine infectious anemia virus vaccine and protection against disease progression.
The equine infectious anemia virus (EIAV) donkey-leukocyte attenuated vaccine (DLV) has been used to protect against equine infectious anaemia (EIA) disease for several decades in China. The attenuated mechanism and immunological protective mechanisms remain to be elucidated. To identify responses that correlate with the protection against disease, we immunized horses with DLV, followed by challenge with an EIAV wild-type strain LN. All vaccinated horses were asymptomatic and had a low level of virus replication (<10 copies ml-1). The expression level of cytokines including gamma interferon, interleukin 2 and 12 in DLV immunized horses was 5-100-fold higher than that in non-vaccinated controls (n=4, P<0.01). After challenge with virulent LN, horses vaccinated with DLV showed lower viral loads (<10(3) copies ml-1) with no temperature increase, except for one transient febrile episode in one animal. In contrast, horses in the non-vaccinated control group experienced much higher viral loads (>10(7) copies ml-1) and intermittent febrile episodes. Cytokine production in the DLV-vaccinated horses increased and attained a plateau level at approximately 50 days post-vaccination, and exceeded 10(7) copies per 10(7) peripheral blood mononuclear cells (PBMCs) 1-3 months post-challenge. However, non-vaccinated control horses died after several fever episodes (>or=39 degrees C), which coincided with higher viral load (10(6)-10(7) copies ml-1) and lower cytokine production (<10(4) copies per 10(7) PBMCs). The results indicate that high levels of EIAV-specific cytokines induced by the attenuated EIAV vaccine may contribute to the protective immune response against EIA disease.
Zhang
Xiaoyan
X
State Key Laboratory for Infectious Disease Prevention and Control, National Center for AIDS/STD Control and Prevention, China CDC, Beijing 100050, China.
Wang
Ying
Y
Harbin Veterinary Research Institute, Harbin 150086, China.
Liang
Hua
H
State Key Laboratory for Infectious Disease Prevention and Control, National Center for AIDS/STD Control and Prevention, China CDC, Beijing 100050, China.
Wei
Li
L
Harbin Veterinary Research Institute, Harbin 150086, China.
Xiang
Wenhua
W
Harbin Veterinary Research Institute, Harbin 150086, China.
Shen
Rongxian
R
Harbin Veterinary Research Institute, Harbin 150086, China.
Shao
Yiming
Y
State Key Laboratory for Infectious Disease Prevention and Control, National Center for AIDS/STD Control and Prevention, China CDC, Beijing 100050, China.
D000818:Animals; D016207:Cytokines / Q000096:biosynthesis*; D018450:Disease Progression; D004859:Equine Infectious Anemia / Q000276:immunology* / Q000517:prevention & control*; D015870:Gene Expression; D006736:Horses; D004860:Infectious Anemia Virus, Equine / Q000276:immunology*; D007371:Interferon-gamma / Q000096:biosynthesis; D018664:Interleukin-12 / Q000096:biosynthesis; D007376:Interleukin-2 / Q000096:biosynthesis; D012333:RNA, Messenger / Q000032:analysis / Q000235:genetics; D012367:RNA, Viral / Q000097:blood; D020133:Reverse Transcriptase Polymerase Chain Reaction; D018417:Th1 Cells / Q000276:immunology; D014613:Vaccines, Attenuated / Q000276:immunology; D019562:Viral Load; D014765:Viral Vaccines / Q000276:immunology*
D016207:Cytokines; D007376:Interleukin-2; D012333:RNA, Messenger; D012367:RNA, Viral; D014613:Vaccines, Attenuated; D014765:Viral Vaccines; D018664:Interleukin-12; D007371:Interferon-gamma