A monoclonal antibody extends the half-life of an anti-HIV oligodeoxynucleotide and targets it to CD4+ cells

An approach was sought to increase the half-life and target cell specificity of antisense oligodeoxynucleotides (oligos). A monoclonal antibody (MAb) was derived from mice immunised with an oligo complementary to a region (1-20) of the HIV genome. This MAb exerts a protective effect on the oligo from the degradation induced by plasma exonucleases in vitro and in vivo. Moreover the anti-oligo MAb dissociates from the oligo in the presence of its complementary sequence to allow hybridization of the two complementary strands. To direct the oligo to CD4⁺ cells the anti-oligo MAb was cross-linked to an anti-CD4 MAb. The heteroaggregate determines a 5-fold increase in the cellular membrane binding of the oligo to CD4⁺ lymphocytes. These findings suggest a new approach to enhancing the therapeutic action and the target specificity of antisense oligodeoxynucleotides useful for the selective inhibition of HIV replication in vivo.