The need for characterization of pathogenicity genes of recombinant DNA viruses used as human vaccines

The region 0.7615-0.796 m.u. of the HSV-1 genome determines suppression of humoral antibody formation against herpes simplex virus

The influence of genetic properties of parts of the HSV-1 genome on suppression of humoral antibody formation was investigated by using intratypic recombinants. The deleted strain HFEM (HSV-1) induces suppression. The MluI DNA fragment (coordinates 0.7615-0.796 m.u.) derived from the antibody inducing strain F1 (HSV-1) was transfected into the deleted strain HFEM to produce the recombinant virus R-M1CI and shown to restore antibody formation, as demonstrated by neutralization- and ELISA-tests. The intratypic recombinant viruses R-15, R-19 and R-26, produced by transfection of the Bam HI DNA-fragment B (0.738-0.809 m.u.) of strain F1 into the deleted strain HFEM, resulted in antibody formation only in the recombinant virus R-26. The reason for these different properties might be associated with the presence of small deletions in the SmaI A-fragment (0.763-0.765 m.u.) or elsewhere in the Bam HI DNA-fragment B. Our results were finally correlated to replication of the recombinant viruses in macrophages and to spread into spleen and adrenal glands. There is evidence that antibody formation may be correlated to the ability of HSV to replicate in macrophages.

Langerhans cells in vaccinia virus infection in mouse skin

Langerhans cells function as potent antigen-presenting cells in the epidermis. They were shown to play an essential role in the mechanisms of defense of the skin against viral infections. In the present study, the response of Langerhans cells to infection of the skin with vaccinia virus was investigated. Decrease in Langerhans cell density in the skin was accompanied by an increase in the pathogenicity of the WR and Noguchi but not of the Lister strain of vaccinia virus. Langerhans cell density was shown to increase rapidly at the site of inoculation with the two pathogenic strains of vaccinia virus.

Role of epidermal Langerhans cells in viral infections

Langerhans cells function as highly potent antigen-presenting cells in the epidermis. In the last few years, their role in viral infections has been studied in various experimental systems. They have been shown to be involved in the pathogenesis of a number of infections of viral origin. These include vaccinia virus, human papilloma virus, herpes simplex virus, foot and mouth disease virus and human retrovirus infections. Studies on the effect of various factors, that are known to modulate the activity and density of Langerhans cell in the epidermis, may lead in the future to the development of new strategies aimed at inhibiting virus infections or even eradicating latent infection.