Pertussis toxin B-oligomer is pleiotropic HIV Tat inhibitor.

2004 MAR 31 - (NewsRx.com & NewsRx.net) -- The pertussis toxin B-oligomer is a pleiotropic inhibitor of the HIV Tat protein.

"HIV-1-transactivating factor Tat contributes to virus replication and to the onset of AIDS-associated pathologies by targeting different infected and uninfected cell types," immunologists in Italy explained.

C. Rizzi and colleagues at the University of Brescia "previously demonstrated that the B-oligomer of pertussis toxin (PTX-B) inhibits HIV infection and replication in primary T cells and macrophages and Tat-dependent HIV-1 long terminal repeat (LTR) transactivation in T-lymphoid Jurkat cells."

In their subsequent study, the collaborators found that "PTX-B inhibits Tat-dependent NF-kappaB activation and HIV-1 LTR-transactivation in non-permissive epithelial HL3T1 cells in a phosphaticlylinositol 3'-kinase-dependent way."

"PTX-B exerts its inhibition both when Tat is produced endogenously in transfected cells and in cells incubated with the extracellular Tat protein," they wrote in the European Journal of Immunology. "In this latter case, PTX-B does not interfere with extracellular Tat uptake by cells."

"PTX-B inhibited also interleukin-8 secretion and virus expression stimulated in chronically infected U1 promonocytic cells by intra- and/or extracellular Tat," test results revealed. "The ...