Recombinant expression and characterization of anti-HIV-1 IgAs

Different antibodies against HIV-1 have been developed at the Department of Biotechnology and have been tested in numerous in vitro studies and some of them also in clinical trials. Among others the mAb 4B3 demonstrated promising results in a macrophage assay infected with virus strain BaL and TV1. To test their potency in an in vitro mucosal system, it is necessary to swith the subclass from IgG to IgA specificity. Naturally occurring IgAs pass the epithelial barrier by cellular internalization via endocytosis with subsequent cleavage of the extracellular part of the receptor which remains at the IgA molecule, known as secretory component. This enables to transport the dimeric IgA from the site of application through the tight epithelial layer to the luminal surface. To test the IgA antibodies in an mucosal application the secretory component must be already coexpressed with the antibody. Therefore, this challenging project needs the expression of a heteropolymeric complex consisting of two antibody specific light and heavy chains connected by the common J-chain and associated with the secretory component. Afterwards the antibodies must be purified and, characterized and tested in different model systems.