INHIBITION OF EARLY AND LATE EVENTS OF THE HIV-1 REPLICATION CYCLE BYCYTOPLASMIC FAB INTRABODIES AGAINST THE MATRIX PROTEIN, P17

Background: The HIV-1 matrix (MA) protein, p17, contains two subcellul ar localization signals that facilitate both nuclear impart of the vir al preintegration complex early during infection and virus particle as sembly late in infection. The dual role of MA in both the afferent and efferent arms of the HIV-1 life cycle makes it an important target fo r intracellular immunization-based gene therapy strategies. Materials and Methods: Here we report, using a new bicistronic vector, that an i ntracellular Fab antibody, or Fab intrabody, directed against a carbox y-terminal epitope of MA from the Clade B HIV-1 genotype, can inhibit HIV-1 infection when expressed in the cytoplasm of actively dividing C D4(+) T cells. Results: Marked inhibition of proviral gene expression occurred when single-round HIV-1 CAT virus was used for infections. In challenge experiments using both laboratory strains and syncytium-ind ucing primary isolates of HIV-1, a substantial reduction in the infect ivity of virions released from the cells was also observed. Conclusion s: This novel strategy of simultaneously blocking early and late event s of the HIV-1 life cycle may prove useful in clinical gene therapy ap proaches for the treatment of HIV-1 infection and AIDS, particularly w hen combined with genetic or pharmacologic-based strategies that inhib it other HIV-1 target molecules simultaneously.