Short-term monotherapy in HIV-infected patients with a virus entry inhibitor against the gp41 fusion peptide.

To infect host cells, most enveloped viruses must insert a hydrophobic fusion peptide into the host cell membrane. Thus, fusion peptides may be valuable targets for developing drugs that block virus entry. We have shown previously that a natural 20-residue fragment of α(1)-antitrypsin, designated VIRus-Inhibitory Peptide (VIRIP), that binds to the gp41 fusion peptide of HIV-1 prevents the virus from entering target cells in vitro. Here, we examine the efficacy of 10-day monotherapy with the optimized VIR-576 derivative of VIRIP in treatment-naïve, HIV-1-infected individuals with viral RNA loads of ≥10,000 copies per ml. We report that at the highest dose (5.0 grams per day), intravenous infusion of VIR-576 reduced the mean plasma viral load by 1.23 log(10) copies per ml without causing severe adverse effects. Our results are proof of concept that fusion peptide inhibitors suppress viral replication in human patients, and offer prospects for the development of a new class of drugs that prevent virus particles from anchoring to and infecting host cells.

Immunoglobulin-like transcripts as risk genes for autoimmunity.

Risk genes for multiple sclerosis (MS) are localized in the gene regions 6p21-11 and 19q13, the latter harboring the genes of the immunoglobulin-like transcripts (ILTs). ILTs are a family of activating and inhibitory receptors expressed on antigen-presenting cells (APCs) as well as on natural killer (NK) and T cells. Because of the inhibitory function of ILT2 and ILT4 and their binding to human leukocyte antigen (HLA)-G, they play a role in immune tolerance and may be important in pathogenesis of autoimmunity. ILT6 shows presence-absence variability and is produced by macrophages in a soluble form. ILT6 deletion is associated with MS. Furthermore, ILT6 activates T cell proliferation and is therefore a candidate gene for autoimmune disorders.