Human MASCs do not cause an immune rejection response in young, healthy rats

ASC Bio's Human MASCs do not cause an immune rejection response in young, healthy rats. Studies using other human adult stem cells use immunocompromised rats or mice. We wondered if human MASCs would cause an immune rejection? So we did a PPD test by injecting human MASCs sub-q into young, healthy, normal rats. Seven rats were injected with 10-20 million cells in 0.5 ml of DMEM. When there was no observed reaction after 2 weeks, the last animal received 42 million cells.  

 On Day 0, a small lump was present:

That was expected because it was 0.5 ml of liquid in the skin.  Control of DMEM alone or rat MASCs had the same bump.  On day 2 the bump was still there, buy by Day 7 it was gone: 

Day 2 top photo, Day 7 bottom photo. This was the same reaction for DMEM alone or rat MASCs in DMEM. If this was a PPD test, then the result would be “negative. Why? Well, MASCs have no MHCII and very low levels of MHCI.