The goal of this experiment is to determine whether
natural killer (NK) cell activity is altered in microgravity.
NK cells are an important part of the immune system, since they are pre-programmed
to destroy virus infected cells and cancerous cells. Therefore it is important
for long term space exploration to characterize whether microgravity and spaceflight
conditions alter the function of NK cells, as this may affect the frequency at
which latent virus infections become reactivated or tumours develop in a long
duration space missions.
The experiment will measure the ability of NK cells from human peripheral blood
to lyse K562 target cells. This will be achieved by using 3H-Uridine labelled
formalin fixed K562 cells which will be mixed with NK cells in-flight, then incubated
for 24h. At the end of the incubation period cells will be filtered from the
medium in-flight, then transferred to refrigerated stowage until post flight
analysis. Post-flight, the amount of radiolabel in the intact target cells (on
the filter) and released from lysed cells (in the medium) will be measured, as
well as cytokine production by the target cells.