Equine alphaherpesviruses (EHV-1 and EHV-4) differ in their efficiency to infect mononuclear cells during early steps of infection in nasal mucosal explants

Annelies P. Vandekerckhove (1) , S. Glorieux (1) , A.C. Gryspeerdt (1) , L. Steukers (1) , J. van Doorsselaere (2) , N. Osterrieder (3) , G.R. van de Walle (4) , H.J. Nauwynck (1)

1 Department of Virology
2 KATHO Catholic University College of South-West Flanders
3 Freie Universität Berlin
4 Faculty of Veterinary Medicine

Equine herpesvirus type 1 (EHV-1) replicates extensively in the epithelium of the upper respiratory tract, after which it can spread throughout the body via a cell-associated viremia in mononuclear leukocytes reaching the pregnant uterus and central nervous system. In a previous study, we were able to mimic the situation in an respiratory mucosal explant system. A plaquewise spread of EHV-1 was observed in the epithelial cells, whereas in the connective tissue below the basement membrane (BM), EHV-1-infected mononuclear leukocytes were noticed. Equine herpesvirus type 4 (EHV-4), a close relative of EHV-1, can also cause mild respiratory disease, but a cell-associated viremia in leukocytes is scarce and secondary symptoms are rarely observed. Based on this striking difference in pathogenicity, we aimed to evaluate how EHV-4 behaves in equine mucosal explants. Upon inoculation of equine mucosal explants with the EHV-4 strains VLS 829, EQ 012 and V01-3-13, replication of EHV-4 in epithelial cells was evidenced by the presence of viral plaques in the epithelium. Interestingly, EHV-4-infected mononuclear leukocytes in the connective tissue below the BM were extremely rare and were only present for one of the three strains. The inefficient capacity of EHV-4 to infect mononuclear cells explains in part the rarity of EHV-4-induced viremia, and subsequently, the rarity of EHV-4-induced abortion or EHM.

Mots clés: EHV-4; hampered spread; basement membrane barrier; mononuclear cells

Domaines: Médecine vétérinaire et santé animale

Annelies P. Vandekerckhove, S. Glorieux, A.C. Gryspeerdt, L. Steukers, J. van Doorsselaere, et al.. Equine alphaherpesviruses (EHV-1 and EHV-4) differ in their efficiency to infect mononuclear cells during early steps of infection in nasal mucosal explants. Veterinary Microbiology, 2011, 152 (1-2), pp.21. ⟨10.1016/j.vetmic.2011.03.038⟩. ⟨hal-00719074⟩