Two different categories of hepatitis B antigen carriers have been investigated. One comprises patients treated with dialysis and known to be highly infectious. The other consists of blood donors found in routine screenings. Serum specimens have been studied with regard to Dane particles, Dane-core-associated DNA polymerase activity, and e-antigen. The two groups differed markedly in the aspects studied. The five healthy blood donors had no, or very few, detectable Dane particles and no detectable DNA polymerase activity; four of the five healthy donors had antibodies against e-antigen. The one sick donor and all six dialysis patients had many Dane particles and polymerase activity; five of the six dialysis patients had e-antigen. Thus, these results further underline the difference between the two groups, and e-antigen and DNA polymerase activity could represent possible useful parameters for judging infectivity.

C is a human cysteine proteinase inhibitor present in extracellular fluids. Cystatin C and a tripeptide derivative (Z-LVG-CHN2) that mimics its proteinase-binding center, were tested for possible antiviral activity against herpes simplex virus type 1 (HSV) and poliovirus type 1. Both recombinant cystatin C and Z-LVG-CHN2 displayed strong inhibitory effects on HSV replication, whereas no significant effect on poliovirus replication was seen. The molar concentration of cystatin C that gave total inhibition of HSV replication was lower than that of either Z-LVG-CHN2 or of acyclovir, the drug currently most used against HSV infections. These results suggest that cysteine proteinase inhibitors might play a physiological role as inhibitors of viral replication and that such proteinase inhibitors, or peptide derivatives that mimic their proteinase-binding centers, might be used as antiviral agents.

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SUMMARYGuinea pig antisera were prepared against purified hexon, penton and fibre antigens of adenovirus type 5. Sera reacting specifically with particular antigens as judged by immunodiffusion, complement fixation and haemagglutination-inhibition tests were assayed for virus neutralizing capacity. The latter was exerted almost exclusively by anti-hexon sera. Type 5 anti-hexon but not anti-fibre sera neutralized type I virus provided the serum virus reaction took place at low pH values.Since the hexon antigens contain the group-specific adenovirus antigen, demonstrable by complement fixation or immunodiffusion, the ability of heterotypic adenovirus rabbit antisera to combine with adenovirus type 5 was assayed. Evidence of such combinations was obtained by the demonstration of virus inactivation following addition of a goat anti-rabbit serum. It was shown that adenovirus type I and type 2 antisera combined with type 5 virus. The technique used did not reveal combinations between type 5 virus and antisera against type 3, type I2, type 2L nor against Coxsackie B. The IgG fractions of rabbit antisera against type i, type 2 and type 12 were shown to enhance inactivation of type 5 virus + antibody complexes. No enhancement was obtained with type 3 or Coxsackie B, IgG. The results suggest that although the hexon antigens contain common structures the cortfigurational pattern differs among the different virus types.

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