Restriction fragment length polymorphism of DQB and DRB class II genes of the ovine major histocompatibility complex.

The ovine major histocompatibility complex (MhcOvar) class II region was investigated by Southern blot hybridizations using ovine probes specific for the second exons of Ovar-DRB and Ovar-DQB genes. Multiple bands were revealed when genomic DNA was digested with each of five restriction enzymes (BamHI, EcoRI, HindIII, PvuII and TaqI), and successively hybridized with the two radiolabelled ovine probes. Restriction fragment length polymorphisms (RFLPs) were analysed in 89 sheep originating from six inbred families and the inheritance of the fragment patterns was determined. Forty-one fragments were recorded with the DQB probe; 32 were detected with the DRB probe. They constituted 9 DQB and 10 DRB allelic patterns. Twelve DQB-DRB haplotypes were resolved in this study.

[Induction of interferon activity in nasal mucus by association of levamisole by systemic route -- inactivated virus by local route (author's transl)]. / Induction d'une activité interféron dans le mucus nasal chex le veau par l'association lévamisole par voie gén,érale-virus inactivé par voie locale.

Calf respiratory disease could have a non-specific origin. The respiratory tract bacterial flora is pathogen only if the animal faces stress which decreases the defense capacities of the respiratory mucosa. The simultaneous administration of UV irradiated IBR virus by nasal route and of levamisole by systemic route induces a protection which is accompanied by interferon synthesis in the nasal mucus. This protection is evaluated experimentally with an infectious IBR virus challenge. In the natural conditions the respiratory disease loses its transmissible aspect in the treated calves.

Transfer of antibodies against the CPD virus through colostrum and milk.

Newborn lamb immunoglobulins are of maternal origin and the transfer is done exclusively by colostrum and milk (syndesmochorial placentation). Antibody levels in colostrum and in maternal serum are the same at the moment of lambing. Milk antibodies are synthesized by cells which invade the udder at the end of the milking period. We immunized ewes with C.P.D. virus during gestation or at the end of lactation and we evaluated the presence of specific neutralizing antibodies in colostrum, in milk and in the sera of the mother and lamb. We recommend vaccination during pregnancy for ewes which are not going to feed their lambs: colostral given protection persists for 3 or 4 weeks. Ewe vaccination when the udder dried up is the choice when natural suckling is used: the lamb is protected as long as it is with its mother. In the conditions used in this work the steroid injection did not interfere with colostral antibody transmission.