NorthWest Biotherapeutics Inc (NWBO)

[Michonne]

For example, NW Bio's old tech uses freeze-thaw approach, doesn't use heat shock, doesn't use TLR agonists, etc. Well, years later it's been discovered that:

"Although activation of the nuclear factor-?B pathway remained intact, the kinase activity of phosphorylated p38 mitogen-activated protein kinase was inhibited in lysate-pulsed DCs. Lysate-induced DC suppression was partially reversed in vitro by induction of tumor cell stress before lysis, and only DCs loaded with stressed lysates afforded protection against tumor challenge in vivo. These data suggest that ex vivo freeze-thaw of tumor cells does not effectively mimic in vivo immunogenic necrosis, and advocates careful characterization and optimization of tumor cell-derived vaccine sources for cancer immunotherapy.

We have previously argued24 that the passive “necrosis” generated by repeated freeze-thaw cycles in vitro is distinct from true pathologic necrosis in vivo, where a variety of immunologic stress signals can be generated. One family of such signals is the heat shock proteins (HSP), which act as both nonspecific immune adjuvants and as chaperones for successful delivery of TAA to antigen presenting cells such as DCs.

Although some studies have shown that stressed apoptotic cells, with induced HSP production, have enhanced immunogenicity, the clinically attractive and simple strategy of freeze-thaw, unmodified lysate-loaded DCs has been widely applied in early trials. This has been despite limited data assessing the interaction between such lysates and DCs, and a failure to address the question of whether their preparation is indeed optimally immunogenic.

As the immune response generated by DCs is related to their maturation state, we hypothesized that DCs, which had taken up TAA in the form of necrotic lysates, and were then matured using a range of TLR agonists, would represent a potent anticancer vaccine. In this study, we show that freeze-thaw lysates in fact inhibit the maturation of DCs in response to a range of TLR ligands, interfere with DC/T-cell interactions, and selectively target particular signaling pathways. To some extent, these effects are shown to be reduced by stressing cells before lysis. These data have important implications for the optimal preparation of tumor cell lysate-based vaccines for clinical application."

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3901408/

Whoops. There are just better methods now.