Gogorza L M, Morán P E, Larghi J L, Seguí R, Lissarrague C, Saracco M, Braun M, Esteban E N
Department of Animal Health and Preventive Medicine, Veterinary School U.N.C.P.B.A., Buenos Aires, Argentina.
Prev Vet Med. 2005 Nov 15;72(1-2):49-54; discussion 215-9. doi: 10.1016/j.prevetmed.2005.07.015. Epub 2005 Oct 25.
Detection of bovine virus diarrhoea virus (BVDV) in one vaccinated beef cattle and three non-vaccinated dairy herds was investigated on peripheral blood leukocytes (PBL) with or without previous treatment followed by a capture ELISA (cELISA). Using the combination of PHA and polycation treatment, PBL from 229 seropositive cattle were studied and could be classified in four different states of BVDV infection. Lysed PBL from four animals were directly positive in cELISA (Category I), PBL of 17 animals were positive after PHA stimulation (Category II), 15 animals were positive only after PHA stimulation plus polycation treatment (Category III), while virus could not be detected in 193 seropositive cattle. Wild-type BVDV strains were isolated by co-culture on polycation-treated MDBK cells from 11 of these seropositive animals. BVDV antibodies of these same animals were able to neutralize their own virus, indicating that virus persists in PBL in spite of strain-specific antibodies. No apparent change of leukocyte subpopulations could be detected in any category of virus-positive animals. Thus, BVDV may be present in the PBL of some cattle, even in the presence of a specific active immune response.
对一头接种过疫苗的肉牛和三个未接种疫苗的奶牛群进行了研究,通过捕获酶联免疫吸附测定法(cELISA),在有无预处理的外周血白细胞(PBL)中检测牛病毒性腹泻病毒(BVDV)。使用PHA和聚阳离子处理相结合的方法,对229头血清阳性牛的PBL进行了研究,并可将其分为四种不同的BVDV感染状态。来自四只动物的裂解PBL在cELISA中直接呈阳性(I类),17只动物的PBL在PHA刺激后呈阳性(II类),15只动物仅在PHA刺激加聚阳离子处理后呈阳性(III类),而在193头血清阳性牛中未检测到病毒。通过在聚阳离子处理的MDBK细胞上共培养,从这些血清阳性动物中的11只分离出了野生型BVDV毒株。这些相同动物的BVDV抗体能够中和自身病毒,这表明尽管存在毒株特异性抗体,病毒仍在PBL中持续存在。在任何一类病毒阳性动物中均未检测到白细胞亚群的明显变化。因此,即使在存在特异性主动免疫反应的情况下,BVDV仍可能存在于一些牛的PBL中。