Cytokine responses to EHV-1 infection in immune and non-immune ponies.
Protecting equids against equine herpesvirus-1 (EHV-1) infection remains an elusive goal. Repeated infection with EHV-1 leads to protective immunity against clinical respiratory disease, and a study was conducted to measure the regulatory cytokine response (IFN-gamma and IL-4) in repeatedly infected immune ponies compared to non-immune ponies. Two groups of four ponies were established. Group 1 ponies had previously been infected on two occasions, and most recently 7 months before this study. Group 2 ponies had no history no vaccination or challenge infection prior to this study. Both groups were subjected to an intranasal challenge infection with EHV-1, and blood samples were collected pre-infection, and at 7 and 21 days post-infection for preparation of PBMCs. At each time point, the in vitro responses of PBMCs to stimulation with EHV-1 were measured, including IFN-gamma and IL-4 mRNA production, and lymphoproliferation. Group 1 ponies showed no signs of clinical disease or viral shedding after challenge infection. Group 2 ponies experienced a biphasic pyrexia, mucopurulent nasal discharge, and nasal shedding of virus after infection. Group 1 ponies had an immune response characterized both before and subsequent to challenge infection by an IFN-gamma response to EHV-1 in the absence of an IL-4 response, and demonstrated increased EHV-1-specific lymphoproliferation post-infection. Group 2 ponies had limited cytokine or lymphoproliferative responses to EHV-1 pre-challenge, and demonstrated increases in both IFN-gamma and IL-4 responses post-challenge, but without any lymphoproliferative response. Protective immunity to EHV-1 infection was therefore characterized by a polarized IFN-gamma dependent immunoregulatory cytokine response.
Department of Medical Sciences, School of Veterinary Medicine, University of Wisconsin, 2015 Linden Drive West, Madison, WI 53706, USA.
Dane K
DK
Coombs
T
T
Patton
Andrea K
AK
Kohler
G
G
Soboll
Cormac
C
Breathnach
Hugh G G
HG
Townsend
D P
DP
Lunn
D000818:Animals; D000914:Antibodies, Viral / Q000097:blood; D049109:Cell Proliferation; D004247:DNA / Q000737:chemistry / Q000235:genetics; D006566:Herpesviridae Infections / Q000235:genetics / Q000276:immunology / Q000662:veterinary* / Q000821:virology; D004861:Herpesvirus 1, Equid / Q000235:genetics / Q000276:immunology*; D006734:Horse Diseases / Q000235:genetics / Q000276:immunology* / Q000821:virology*; D006736:Horses; D007371:Interferon-gamma / Q000096:biosynthesis / Q000235:genetics / Q000276:immunology*; D015847:Interleukin-4 / Q000096:biosynthesis / Q000235:genetics / Q000276:immunology*; D007963:Leukocytes, Mononuclear / Q000166:cytology / Q000821:virology; D008297:Male; D009297:Nasal Mucosa / Q000821:virology; D009500:Neutralization Tests / Q000662:veterinary; D016133:Polymerase Chain Reaction / Q000662:veterinary; D012333:RNA, Messenger / Q000096:biosynthesis / Q000235:genetics
D000914:Antibodies, Viral; D012333:RNA, Messenger; D015847:Interleukin-4; D007371:Interferon-gamma; D004247:DNA