There are LOTS of DC vaccines, and the methods to make them have been in the scientific literature since the 1980's.  Some work better than others, but Dendreon's Provenge is the only one that made it to market where it promptly failed for economic reasons.  There is a long list of companies that died after spending nine-figures developing autologous vaccines.

 

If an academic center wants to do a combination product study with a mAb and a vaccine, it is simpler to do it with a "home grown" vaccine, especially if there is an existing IND.