"Packaging" is the process by which AAV preparations are generated - meaning the process by which a linear single-stranded DNA sequence is encapsidated within a viral protein coat. AAV preparations are generated using a plasmid-based (helper virus-free) packaging protocol in 293T cells, either in-house by Addgene scientists or through collaboration with viral vector manufacturing facilities.
The plasmids are delivered via triple co-transfection of the transfer plasmid (which contains AAV2 ITRs), a plasmid encoding the AAV2 rep gene plus a serotype-specific cap gene, and finally a third plasmid encoding adenoviral helper sequences. The viral particles produced by the cells are therefore a "pseudotype" that can be denoted by AAV2/x - where "x" is the serotype conferred by the aforementioned rep/cap plasmid. In our catalog, these are called simply "AAVx" particles - namely by the indexing catalog ID numbers. In other words, an AAV2/5 preparation of plasmid 49055 would have a catalog ID of "49055-AAV5." For a table with AAV packaging plasmids, please see our AAV Plasmids page.
The linear DNA sequence flanked by the ITRs (in the aforementioned "transfer plasmid") is what gets packaged into the AAV particles. Given the fact that the AAV2 ITRs themselves are the only native viral sequences present in the rAAV (recombinant AAV) genome, the particles have only ~6% of the wild-type virus genome within them. The rep/cap and the adenoviral helper plasmid sequences which are provided in trans are not packaged, and are only involved in producing proteins that encapsulate this linear genome within the serotype-specific protein coat (the capsid). The adenoviral (AdV) sequences are therefore lost in the process, as the naked plasmid DNA is eventually degraded after transfection of the 293T cells.
More information regarding our general AAV production protocol and quality control can be found on our Viral Production page.