The invention is directed to the use of peptides that can bind and block the interaction of α1 proteinase inhibitor (α1PI) and one or more molecules, for example antibodies to HIV-1 envelope proteins. The invention features methods of activating α1PI in a cell, methods of treating or preventing a disease or disorder in a subject, for example HIV-1 or AIDS. The invention also features pharmaceutical compositions comprising one or more peptides that block the interaction of α1 α1PI and one or more molecules. Also included in the invention are kits.
