Radioimmunoassay for the Major Structural Protein of Hamster Type C Viruses

Abstract

A radioimmunoassay for the major, group-specific antigen (p30) of hamster type C viruses was developed. The test detected -5 ng of viral protein per ml and was highly specific for hamster viruses when used with homologous antibody. Comparison of three hamster viruses, two being mouse-hamster pseudotypes, in homologous and heterologous intraspecies assays, showed no evidence of type specificity for these proteins. The pseudotype viruses showed no evidence of mouse virus p30 antigenic determinants. An interspecies antigen assay employing 1251-labeled hamster p30 and anti-feline p30 was completely inhibited by cat (feline leukemia virus), hamster, and rat viruses, to a slightly lesser degree by mouse viruses, and only poorly by RD 114 and Gibbon ape viruses. The Mason-Pfizer virus did not inhibit this assay. Hamster p30 was detected by radioimmunoassay in individual embryos from two LSH hamsters and in several adult tissues, excluding muscle at levels below that required for detection in complement-fixation tests.

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

“…Limited, low affinity binding of antibody was observed with some competing proteins at concentrations 10to 100-fold greater than the labeled antigen; this can be attributed to binding of the small proportion of cross-reactive antibodies by the interspecies determinants of the competing protein. Similar results obtained with the woolly monkey and RD 114 virus proteins have been reported by Parks et al (36) and Goldbert et al (17) and with the hamster virus protein by Charman et al (7).…”

“…The extent to which these determinants were common to the other two viruses was then tested by the effectiveness of the proteins of each virus to compete for antibody binding. In part, similar analyses have been reported by Stephenson and Aaronson (51), Parks and Scolnick (35), and Charman et al (7).…”

“…Group specificity of the p27 to p30 proteins. The predominant antigenic reactivity of the p27 to p30 proteins of type-C RNA viruses is known to be specific to viruses of a given group (7,14,18,35,43,44,54). The present experiments, in which each of the four purified '251-labeled proteins was precipitated by its homologous antiserum and the displacement by the four unlabeled proteins was analyzed, provide a quantitative estimate of the extent of this specificity.…”

“…Of these, the most broadly reactive is the major internal protein (57; Strand and August, unpublished data). Studies of the related determinants of this protein have shown cross-reactivity between all species of mammalian type-C viruses tested (7,13,35,51,54) and a high degree of amino acid sequence homology of several mammalian type-C viruses has been shown by Oroszlan et al (34).…”

Felv epidemiology in los angeles cats: Appraisal of detection methods

“…Tubes were then centrifuged for 20 min at 3,000 g, supernatants decanted to waste, and precipitate radioactivity determined in a Nuclear Chicago model 1185 Autogamma Counter with an efficiency for 1251 of about 80 %. Data reduction was as previously published (Charman, 1974). This assay detects FeLV p30 at concentrations of 1-5 ng/ similar to conventional double antibody RIAs, 2.…”