[Inhibition of adenovirus reproduction in cell culture by specific antibodies].

The capacity of specific antibodies to inhibit the reproduction of homo- and heterologous adenoviruses in Hela cell added to culture medium after virus adsorption was studied. The inhibiting effect of polyclonal antivirus and monospecific antihexone antibodies to homo- and heterologous adenoviruses was shown. The effect was more expressed when using antibodies to homologous antibodies. The intensity of inhibition depended on antibodies concentration in the medium and infecting dose of the virus. Essential reduction of the quantity of infected cells and a decrease of the titer of adenovirus synthesized in the presence of homo- and heterologous antibodies was shown but adenovirus reproduction was not inhibited completely.

[Stability of the structure and antigenic determinants of adenovirus type 1 native hexon to proteases]. / Ustoichivost' struktury i antigennykh determinantov nativnogo geksonaadenovirusa tipa 1 k proteazam.

Hexon capsomers of human adenovirus type 1 (h1) labeled by iodine 125 were digested in a native state (trimers) by trypsin, chymotrypsin or papain, and the resulting hydrolysates were analyzed by SDS-PAGE. In each case, a discrete and temporally stable pattern of relatively large fragments was revealed. The degree of hexon polypeptide hydrolysis was maximal for papain, intermediate for chymotrypsin and minimal for trypsin, the largest fragments in the digest being 32, 40 and 80 kD, respectively. At room temperature, all the electrophoretically discernible hexon proteolytical fragments were held together in structures resembling intact hexon trimers and could be regarded as "hexon cores", of which papain hexon cores were the most stable during SDS-PAGE. Radioimmunoprecipitation analysis revealed a complete absence of native hexon antigenicity in thermodenaturated fragments of hexon protease digests, while native trypsin, chymotrypsin and papain hexon cores could be precipitated by hexon-specific antibodies. The immunoprecipitated material contained all of the hexon fragments found in appropriate hexon cores and retained the structure of the original cores. Trypsin, chymotrypsin and papain hexon cores were shown to possess at least part of native Ad h1 hexon antigenic determinants of each of the following specificities: species-specific (epsilon), cross-reactive with hexon of human adenoviruses (h3 and h6), simian adenovirus (sim 16), bovine adenoviruses (bos 3 and bos 7) and avian adenovirus (Aviadenovirus gal 1 or CELO). Thus, the full spectrum of known hexon antigenic determinants (species-specific to intergenus-crossreactive) is at least portly stable against protease attack of native hexon capsomers.

Changes of adenovirus hexon associated with different passage history of Ad h 1.

Two descendants of the prototype strain AD71-Washington D. C. were obtained by independent passaging for at least 18 years in Kiev, and in Budapest (Ad h 1 kappa, and Ad h 1B, respectively). By restriction endonuclease mapping, the DNA was identical corresponding to the patterns of human adenovirus type 1. In spite of this, SDS-polyacrylamide gel electrophoresis revealed that the purified hexon of Ad h 1 kappa was of lower Mr than the subunit of Ad h 1B. In contrast to this, the native capsomer (hexon) of Ad h 1 kappa exhibited lower electrophoretic mobility in agarose gel electrophoresis than the native hexon of Ad h 1B. Oligopeptide mapping of the main hexon bands from SDS-polyacrylamide gels revealed the presence of unique spots among the chymotryptic oligopeptides of Ad h 1B, too. Thus, the differences in the sensitivity to proteolytic cleavage during purification seem to have a structural basis. Antigenic analysis of the native hexon capsomers was performed using polyclonal antihexon immunsera. Immunodiffusion, immunoelectrophoresis, and competitive RIA were used for comparison. The results indicate that native hexon capsomers of Ad h 1 kappa and Ad ha 1B possess antigenic differences within the type-specific regions, nevertheless, their genetic background could not be detected by the restriction endonucleases applied. It cannot be excluded that the differences were results of altered assembly of virions under different passage conditions.

[Radioimmunological analysis of simian adenovirus SA7 hexon]. / Radioimmunologicheskii analiz geksona adenovirusa obez'ian SA7.

Direct and competitive radioimmunoassay (RIA) identified several antigenic determinants in hexone of adenovirus (Ad) of lower primates SA7: a species-specific, one common for Ad SA7 and SV38, as well as 2 genus-specific determinants: one common for the studied human Ad types 1 and 6, simian Ad SA7 and SV38, cattle AD of type 3, and a new determinant common for human Ad type 6 and simian Ad SA7 and SV38. It is proposed that the above genus specific determinants be designated alpha 1 and alpha 2, respectively. Indirect evidence of the occurrence in nature of rabbit Ad was obtained as sera from some nonimmunized animals precipitate purified labeled SA7 hexone, i.e. contain antibodies to the genus-specific determinant of the hexone.