20 research outputs found
Analysis of ORF 1 in European porcine reproductive and respiratory syndrome virus by long RT-PCR and restriction fragment length polymorphism (RFLP) analysis
Determination of 5 '-leader sequences from radically disparate strains of porcine reproductive and respiratory syndrome virus reveals the presence of highly conserved sequence motifs
Sensitive detection and typing of porcine reproductive and respiratory syndrome virus by RT-PCR amplification of whole viral genes
Heterologous challenge with porcine reproductive and respiratory syndrome (PRRS) vaccine virus: no evidence of reactivation of previous European-type PRRS virus infection
Experimental infection with the Paderborn isolate of classical swine fever virus in 10-week-old pigs: determination of viral replication kinetics by quantitative RT-PCR, virus isolation and antigen ELISA
Epitope mapping porcine reproductive and respiratory syndrome virus by phage display: the nsp2 fragment of the replicase polyprotein contains a cluster of B-cell epitopes
Porcine humoral immune responses to multiple injections of murine monoclonal antibodies
In humans and cattle, multiple injections of murine monoclonal antibodies (m-mAbs) induce anti-mouse antibody responses. The objectives of the present. study were to investigate whether a similar response could be seen when pigs were subjected to m-mAb therapy, and to study the kinetics of such a response. In two separate animal experiments, long-term treatment was performed with m-mAbs at low-dose levels and therapeutic levels, respectively. Two specific m-mAbs that recognized cognate antigen in the pigs (CD4 and CD8 surface antigens on T-lymphocytes) and two irrelevant control m-mAbs having no cognate antigen in the pigs were used. Enzyme-linked immunosorbent assays (ELISA) were used to quantitate the circulating m-mAbs, as well as the induced pig anti-mouse antibodies (PAMA), in serum samples from m-mAb-treated pigs. As expected, we generally saw vigorous PAMA responses within 10 days aft er the start of m-mAb treatment with the specific m-mAbs. However, the different mAbs showed striking differences in the kinetics and levels of PAMA responses, differences that might be ascribed to the m-mAb formulation and epitope specificity. In conclusion, treatment of pigs with m-mAbs against T-cell surface antigens induced rapid PAMA responses. This may influence and possibly decrease the effect of the m-mAb treatment by narrowing the time period where m-mAbs can efficiently be used for cell depletion
Analysis of ORF 1 in European porcine reproductive and respiratory syndrome virus by long RT-PCR and restriction fragment length polymorphism (RFLP) analysis
Reversion of a live porcine reproductive and respiratory syndrome virus vaccine investigated by parallel mutations
g parallel mutations might be seen as second-site compensatory mutations for one or more of the mutations that accumulated in the vaccine virus sequence during cell-culture adaptation. Evaluation of the remaining mutations in the ORF1 sequence revealed stronger selective pressure for amino acid conservation during spread in pigs than during vaccine production. Furthermore, it was found that the selective pressure did not change during the time period studied. The implications of these findings for PRRS vaccine attenuation and reversion are discussed. Introduction Live attenuated virus vaccines are used worldwide in both humans and animals. Although this kind of vaccine is generally considered safe, reported cases of reversion to virulence have highlighted the inherent safety problems in the use of traditional live attenuated vaccines (Cizman et al., 1989 ; Christensen et al., 1992 ; Minor, 1993 ; Xie et al., 1998