HSP70 did not
activate NK cells directly. Instead, HSP70 induced the expression
of an NKG2D ligand MICA on DCs, which then activated NK cells in
an NKG2D-dependent manner.
DCs are the most powerful professional
antigen presenting cells (APCs) that are instrumental in processing
antigens and orchestrating antigen-specific adaptive immunity and
tolerance
NK cells and DCs can functionally interact with each other both in
vitro and in vivo
autologous HSP70 could stimulate significant IFN-γ production
The magnitude
of the IFN-γ response was different from patient to patient and correlated
with the number of functional NK cells
In addition, 10 out of 14 patients had significantly
increased IFN-γ producing cells in the peripheral blood after HSP70 vaccinations,
which is again in line with increased NK cell activity as reported
in our original study in these patients