If fulminate rejection in allogeneic and xenogeneic engraftments is not an evolutionary relict feature, then any treatment that ablates the host surveillance's effector arms capabilities and eliminates graft vs. host reactivity should induce donor chimerism in transplant settings. We demonstrate here marked proliferative response of Botryllus (Urochordata) blood cells months following their infusions (2×104-105 blood cells per host) into the concordant xenogeneic environment of irradiated Botrylloides soma. The state of infused cells was followed by Botryllus specific microsatellite alleles on DNA samples from host zooids and vascular system. Increased growth rates and life spans of engrafted hosts in some cases, and sudden chimerical death following the outbreak of donor cells in others, indicate a 'double-edged sword' expression of concurrent evolutionary selected mechanisms. This DES phenomenon in immunity underlies divergent stem cell competition phenomena in multicellular organisms, leading in mammals, to cases of autoimmune diseases vis-à-vis long-lasting microchimerism events following an iatrogenic transplantation.
Bibliographical noteFunding Information:
We are grateful to C. Rabinowitz for technical assistance. Funded by grants from the NIH (ROI-DK54762), the Israel Science Foundation (456/01) and the US–Israel Binational Science Foundation. N.S.-B. was a doctoral fellow of Ch. Clore Foundation. This study is part of N.S.-B. PhD dissertation at Bar-Ilan University.
- DES, double-edged sword
- Stem cells