Pathogenesis of defective retroviruses.

ABSTRACT

Concerns about the presence of contaminating defective retroviruses in cells used for vaccine preparations have been raised. These concerns mainly reflect the fact that (i) most species harbour several copies of endogenous defective and/or non-defective retroviral sequences in their genome; (ii) these sequences have frequently been found to participate in recombination events giving rise to novel viral entities; and (iii) several strains of defective retroviruses have been shown to be pathogenic. Here, a brief description of the main features of defective retroviruses is provided. In addition, the characteristics and plasticity of defective retroviruses are illustrated with a defective retrovirus inducing a mouse disease, murine AIDS (MAIDS).