Cre-GFP AAV (Serotype AAV-BI30)

AAV serotype refers to a specific variant of the adeno-associated virus (AAV) that differs in the composition of its capsid proteins. These capsid proteins determine the tropism of the virus, i.e., its ability to infect and transduce specific types of cells and tissues. The term "serotype" is derived from the immune response: each serotype has different antigens that are recognized differently by the immune system. For example, AAV2, AAV5, and AAV9 are different serotypes, each with unique targeting and delivery properties. This targeting ability is critical to the success of gene therapy and research applications. Different AAV serotypes are naturally occurring or artificially synthesized variants. To date, at least 13 natural AAV serotypes and more than 100 variants have been identified.

AAV-BI30 exhibits a remarkable ability to specifically infect and transduce CNS endothelial cells. It is stably expressed in mouse and rat models, as well as in human microvascular endothelial cells in vitro. AAV-BI30 is based on the AAV9 capsid with specific modifications. It has a 7-mer inserted between amino acids 588 and 589 of the VP1 protein. In addition, it carries the K449R mutation and the NNSTRGG insertion at the same position. In particular, the AAV9 engineered capsid variant AAV-BI30 was recently shown to effectively transduce brain, retinal, and spinal cord vascular endothelial cells after systemic administration. However, AAV-BI30 also exhibits a broad tropism for peripheral organs, especially the liver, which may lead to hepatotoxicity in treated mice.