Affiliation: P2-P3 Laboratories, DIBIT, Via Olgettina n. 58, 20132, Milano, Italy.
The innate immune system accounts for the fastest defense response to microbial invasion although, conversely, several pathogens can modulate the host response resulting in a modulation of their survival and propagation. In this regard, some bacterial toxins possess immuno-stimulating properties that have been exploited in terms of vaccine adjuvanticity and induction of specific cytotoxic T lymphocytes. Among these, Bordetella pertussis toxin (PTX) possesses the ability of modulating the immune responses in multiple ways, as demonstrated in vivo as well as in ex-vivo and in vitro experimental systems. In addition, PTX, as well its nontoxic B-oligomer PTX-B and the genetically inactivated PT-9K/129G molecule, have been recently shown to inhibit infection of primary cells, lymphoid organs and cervical tissue by the human immunodeficiency virus type 1 (HIV-1), the etiological agent of the acquired immunodeficiency syndrome. This article focuses on the regulation of the immune response and on the anti-viral properties of PTX and of its nontoxic related molecules as an example of exploitation of a natural bacterial product to combat viral infections.