Isoelectric spectrum and titration curves of Aleutian disease virus proteins

Abstract

Three major virus‐specific proteins (Mr = 85 000, 75 000 and 25 000) were detected in purified preparations of the cell culture‐adapted Aleutian disease virus (ADV) SL3 isolate according to their molecular weight, isoelectric point and titration curve, For all structural proteins, amino acid sequence homologies were demonstrated by proteolytic peptide mapping. The virus‐induced protein Mr 75 000, detected only in lysates of infected cells, revealed a different proteolytic peptide map. It was shown that each of the structural proteins, although demonstrated to be homogeneous in molecular weight, consists of multiple species differing in their isoelectric points. Protein modifications are discussed as possible cause for the charge variations of ADV structural proteins.

Epitopic Mapping of Structural and Nonstructural Aleutian Disease Virus Proteins

“…The p25 polypeptide found consistently in crude cell lysates and in partially purified preparations of ADV SL3 [4] was shown to be antigenetically related to p85 and p75. It was recognized by all mAbs reactive against p85 and p75 (table I).…”

“…The nonstructural components have different molecular and antigenic characteristics and are encoded in the 3' half sequence of the parvovirus ge nome [1,2], For the two structural proteins (p85 and p75) of Aleutian disease virus (ADV), an au tonomously replicating parvovirus, exten sive peptide homology was revealed using proteolytic digestion. In turn, no obvious homology was found between structural (p75, p85) and nonstructural (p71) ADV pro-teins [3,4]. These findings suggest that the structural ADV polypeptides have a com mon genetic origin, and hence by analogy to other parvoviruses [1], are antigenically re lated.…”

“…It has been postulated that they result from in vivo virion degradation during ADV in fection, whereas ADV propagated in cell cul tures was assumed to contain only nondegraded p85 and p75 polypeptides [26]. Fur ther study will be undertaken to elucidate whether the p25 polypeptide, which differs from p85 and p75 in molecular weight, iso electric spectrum, and titration curve but shares their molecular [4] and antigenic char acteristics (table I), originates from in vitro proteolytic cleavage and constitutes only an artifact. Alternatively, the p25 polypeptide may be a structural protein of the ADV parti cle.…”

“…In turn, because the digest of the ADV p71 protein contained different peptides, another molec ular characteristic of this nonstructural, vi rus-induced protein [3,4] was shown.…”

Topographical analysis of the G virion of Aleutian mink disease parvovirus with monoclonal antibodies

“…Classical infections in adult mink are characterized by chronic viremia, extremely high levels of antiviral antibodies, hypergammaglobulinemia, and circulating immune complexes [10,31,32]. The immune complexes play a prominent role in the pathogenesis of immune complex-mediated glomerulonephritis and arteritis that afflicts adult mink chronically infected with ADV [20,32]. Viral proteins can be detected as breakdown products in vivo, with relative molecular weights between 14,000 and 30,000 kDa [1,37].…”