Structural proteins of mammalian RNA tumor viruses: relatedness of the interspecies antigenic determinants of the major internal protein

Abstract

The relatedness of antigenic determinants of purified major core proteins of the murine, feline, RD 114/baboon, and woolly monkey/gibbon ape groups of RNA tumor viruses was examined by competition radioimmunoassay. In assay systems of a homologous antigen and antiserum, high affinity competition for binding to all of the antibodies was observed only with the homologous unlabeled protein; the core proteins of other groups of viruses showed only low affinity binding of a small fraction of antibodies, presumably those reactive with the interspecies determinants, at concentrations of competing protein 10to 100-fold greater than that of the labeled antigen. The cross-reactive (interspecies) antigens of every two viruses were selectively examined by precipitating the purified 125I-labeled protein with antiserum against each of the other proteins. The extent to which these shared determinants were common to the other viruses was then tested by the effectiveness of the proteins of each virus to compete for antibody binding. Several classes of interspecies determinants were distinguished: those common to two of the groups of viruses, others to three, and some to all four. Moreover, an even greater variety of interspecies determinants was indicated by differences in the affinity of the individual proteins for antibody binding, supporting the hypothesis that there are at least several, if not many, different interspecies determinants with a broad spectrum of antigenic crossreactivity. These studies suggest that the murine and feline viruses are closely related as they contain cross-reactive antigenic determinants not shared with the other viruses, that the feline virus is more closely related to the woolly monkey virus than to RD 114, and that the RD 114 and woolly monkey viruses retain interspecies determinants shared relatively equally with each of the other viruses.

Proteins of bovine leukemia virus. I. Characterization and reactions with natural antibodies

“…(v) There was no cross-reactivity in a radioimmunoassay competition using 1251-labeled Rauscher-murine leukemia virus p30 precipitated by a goat antifeline leukemia virus antiserum. This test detects antigenic interspecies determinants that are common to the major internal protein of murine and feline leukemia viruses shared also by most of the other mammalian type C viruses (22).…”

Application of a Novel Radioimmunoassay to Identify Baculovirus Structural Proteins That Share Interspecies Antigenic Determinants

“…Nucleotide sequence homology studies and radioimmunoassays (RIAs) are two of the more sensitive methods used to demonstrate genetic relatedness among viruses and similar antigenic determinants in viral gene products, respectively. It is well established that conserved antigenic determinants are more readily detected than their corresponding nucleotide sequences (1,21,34). For example, a sensitive RIA was recently used to demonstrate an immunological linkage between retroviruses which had diverged to the point where base sequence homology could no longer be detected (5).…”

Humoral immune responses of cats to mammalian type‐C virus p30s

“…An additional possibility is that this represents a response to RD114 and that the MuLV probe was more immunereactive. In this regard, Strand and August (1975) have recently shown that the combination of labelled MuLV p30 and anti RDl14 p30 produce a broadly reactive assay similar to that seen with this cat serum. An additional possibility is that these antibodies are directed against a p30 of distinct specificity, for example, a third class of cat type-C viruses.…”