Protection against myxomatosis and rabbit viral hemorrhagic disease with recombinant myxoma viruses expressing rabbit hemorrhagic disease virus capsid protein

Two myxoma virus-rabbit hemorrhagic disease virus (RHDV) recombinant viruses were constructed with the SG33 strain of myxoma virus to protect rabbits against myxomatosis and rabbit viral hemorrhagic disease. These recombinant viruses expressed the RHDV capsid protein (VP60). The recombinant protein, which is 60 kDa in size, was antigenic, as revealed by its reaction in immunoprecipitation with antibodies raised against RHDV. Both recombinant viruses induced high levels of RHDV- and myxoma virus-specific antibodies in rabbits after immunization. Inoculations by the intradermal route protected animals against virulent RHDV and myxoma virus challenges

Atrophy of primary lymphoid organs induced by Marek's disease virus during early infection is associated with increased apoptosis, inhibition of cell proliferation and a severe B-lymphopenia

Marek's disease is a multi-faceted highly contagious disease affecting chickens caused by the Marek's disease alphaherpesvirus (MDV). MDV early infection induces a transient immunosuppression, which is associated with thymus and bursa of Fabricius atrophy. Little is known about the cellular processes involved in primary lymphoid organ atrophy. Here, by in situ TUNEL assay, we demonstrate that MDV infection results in a high level of apoptosis in the thymus and bursa of Fabricius, which is concomitant to the MDV lytic cycle. Interestingly, we observed that in the thymus most of the MDV infected cells at 6 days post-infection (dpi) were apoptotic, whereas in the bursa of Fabricius most of the apoptotic cells were uninfected suggesting that MDV triggers apoptosis by two different modes in these two primary lymphoid organs. In addition, a high decrease of cell proliferation was observed from 6 to 14 dpi in the bursa of Fabricius follicles, and not in the thymus. Finally, with an adapted absolute blood lymphocyte count, we demonstrate a major B-lymphopenia during the two 1st weeks of infection, and propose this method as a potent non-invasive tool to diagnose MDV bursa of Fabricius infection and atrophy. Our results demonstrate that the thymus and bursa of Fabricius atrophies are related to different cell mechanisms, with different temporalities, that affect infected and uninfected cells

Differential expression of Marek's disease virus (MDV) late proteins during in vitro and in situ replication: Role for pUL47 in regulation of the MDV UL46-UL49 gene locus

Marek's disease virus (MDV) is a lymphotropic alphaherpesvirus that replicates in a highly cell-associated manner in vitro. Production of infectious cell-free virus only occurs in feather follicle epithelial (FFE) cells of infected chicken skins. Previously, we described differential expression for a core alphaherpesvirus protein, pUL47 that was found to be abundantly expressed in FFE cells of infected chickens, while barely detectable during in vitro propagation. Here, we further examined the dynamics of expression of four tegument proteins within the UL46-49 locus during in vitro and in situ replication. All four proteins examined were expressed abundantly in situ, whereas both pUL47 and pUL48 expression were barely detectable in vitro. Replacement of the putative UL47 and UL48 promoters with the minimal cytomegalovirus promoter enhanced mRNA and protein expression in vitro. Interestingly, enhanced expression of pUL47 resulted in increased UL46, UL48, and UL49 transcripts that resulted in increased pUL46 and pUL48 expression

11th International Symposium on Marek's Diseases and Avian Herpesviruses

International audienc

Statistical methods for the comparison of antibody levels in serums assayed by enzyme linked immunosorbent assay

International audienc

ESCDL-1 cell-line derived from chicken ES cells is fully permissive to Mardiviruses

National audienc

Procédé de sélection d'une lignée cellulaire permissive pour la réplication de virus aviaires

The present invention relates to a method for obtaining an untransformed avian cell line enabling in vitro avian virus replication. Said method includes the following steps: a) culturing avian embryonic stem cells in the presence of a stroma for at least 3 days; b) culturing for at least 2 days in a medium having a low serum concentration; c) culturing for at least 2 days in a medium having a low serum concentration containing 1 to 10 mM of hexamethyleme bisacetamide (HMBA); d) culturing for at least 10 days in a medium having a low serum concentration; and e) culturing or freezing an avian cell line enabling avian virus replication. The invention also relates to the resulting cell line and to the use thereof in vaccine preparationsLa présente invention concerne un procédé d'obtention d'une lignée cellulaire aviaire non transformée permettant la réplication de virus aviaires in vitro, comprenant les étapes suivantes : a) Mise en culture de cellules souches embryonnaires aviaires en présence d'un stroma pendant au moins 3 jours; b) Culture dans un milieu à faible concentration de sérum pendant au moins 2 jours; c) Culture dans un milieu à faible concentration de sérum comprenant entre 1 et 10 mM de hexaméthylène bisacétamide (HMBA), pendant au moins 2 jours; d) Culture dans un milieu à faible concentration de sérum pendant au moins 10 jours; e) Culture ou congélation d'une lignée cellulaire aviaire permettant la réplication de virus aviaires. L'invention est également relative à la lignée cellulaire ainsi obtenue, et à son utilisation dans des préparations vaccinales