Effect of 6-azacytidine on the course of experimental adenoviral infection in newborn Syrian hamsters.

Adenoviral infection is a serious human pathology leading to respiratory, gastrointestinal and ocular disorders and epidemic outbreaks, especially in children's groups. Here we present the results from an investigation of anti- adenoviral effect of 6-azacytidine (6-AC) both in vitro and in vivo. The selectivity index of 6-AC for adenovirus type 5 in HEp-2 cells was 374, the 50% effective concentration was 0.5 mg/ml. For in vivo investigations we developed a model of disseminated adenoviral infection in newborn Syrian hamsters. The infectious virus was recovered from the liver, kidney, lungs and heart. Application of 6-AC led to a reduced period of the virus presence (7 days in the liver and 4 days in the kidney and heart) and lowered virus titers on day 3 post-inoculation (p.i.) (liver - 2.7 and 4.1, heart - 0 and 3.2, kidney - 0 and 2.4 log(10 )CPD(50)/mg tissue weight, in the presence and absence of 6-AC, respectively). Application of 6-AC to newborn Syrian hamsters led to partial destruction of their splenocytes. The results obtained suggest that 6-AC or 6-ACbased drugs with lower toxicity or applied topically may be suitable for therapy and prevention of adenoviral infection in humans.

Structure--antiadenoviral activity of nitrogen containing macroheterocycles and their analogues.

The search for the inhibitors of adenoviruses has been performed among the substances of new class NCM (nitrogen containing macroheterocycles) and their analogues that have high potential of pharmacological properties. We have found a number of NCM and their derivatives that inhibit the reproduction of adenoviruses to various degrees. For the prediction of NCM structure with antiadenoviral activity we have performed the computer modeling using QSAR approach on the basis of simplex representation of molecular structure (SiRMS).

Detection of plant viruses using a surface plasmon resonance via complexing with specific antibodies.

The use of instrumental systems based on the surface plasmon resonance (SPR) for rapid diagnosis of intact plant viruses (in particular, tobacco mosaic virus (TMV)) is considered. A new approach using detection of viral antigen and antibody (IgG) complexes formed during the preincubation step (instead of their consecutive application in classical approach) is discussed. A comparison between signal level registered from the mixture of virus and specific serum and that from the sample without virus (samples deposited onto the sensor surface treated with thiocyanate and protein A Staphylococcus aureus) allows unambiguous detection of viral particles in the material studied. The performance capabilities of the method are discussed and illustrated by quantitative detection of virus in the actual samples (cells homogenate) at high concentration.

Simple method for plant virus detection: effect of antibody immobilization technique.

The possibility has been demonstrated for applying a surface plasmon resonance for detecting plant viruses in real samples. An optimal mode for antiviral immunoglobulin immobilization on sensor surfaces is described. Out of three proposed techniques for sensor surface treatment, namely, unmodified gold surface, gold surface treated with (a) thiocyanate and (b) thiocyanate and protein A (Staphylococcus aureus), the latter was chosen as most suited for retention of the formed native immunoglobulin layer.

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.

Polypeptides and immunoreactivity of empty adenovirus type 1 particles.

Two distinct CsCl-stable empty particle populations were characterized in human adenovirus type 1 infected cells. Different sensitivity to proteases and polypeptide composition indicate that empty capsids A and B are degradation products of two different assembly intermediates. Both empty particle populations react with antihexon antibodies similarly to complete virions. Thus the arrangement of exposed type-specific epitopes is suggested to be unchanged during virus assembly. Experimental evidence is presented that both antifibre and antihexon antibodies trigger structural changes of complete virions, which are initiating the specific loss of core protein V from antibody-aggregated virions.