Indications of immunodepression in chickens infected with various strains of Marek's disease virus.
The effect of infection by various strains of Marek's disease virus (MDV) on the immune function of 3-week-old chickens was examined. MDV strains of low (CU-2, RB-7) and high (RB-3, MD-5, and MD-11) pathogenicity were compared with prototype JM-10 strain of moderate pathogenicity. Mortality, whole body weight, relative weights of lymphoid organs, histopathology, humoral antibody responses to thymus-dependent and -independent antigens, and in vitro lymphocyte responses to mitogen stimulation were investigated at 1, 2, and 3 weeks postinfection. MDV strains of high pathogenicity significantly depressed responses at 3 weeks postinfection, seeming to indicate the ability of these viruses to induce severe immunodepression. However, the fact that the moderately pathogenic and even some of the low-pathogenicity strains induced immunodepression suggests that other viral mechanisms are also important in its determination.
Rivas
A L
AL
Department of Avian and Aquatic Animal Medicine, New York State College of Veterinary Medicine, Cornell University, Ithaca 14853.
Fabricant
J
J
D000818:Animals; D000917:Antibody Formation; D002060:Bursa of Fabricius / Q000473:pathology; D002645:Chickens / Q000276:immunology*; D008381:Herpesvirus 2, Gallid / Q000472:pathogenicity; D007111:Immunity, Cellular; D007153:Immunologic Deficiency Syndromes / Q000209:etiology / Q000662:veterinary*; D008380:Marek Disease / Q000276:immunology* / Q000473:pathology; D009929:Organ Size; D013154:Spleen / Q000473:pathology; D013950:Thymus Gland / Q000473:pathology