[On the occurrence of phenoloxidase containing cells (POZ) in nude mice]

Nude mice, who are deficient in T-lymphocytes, were investigated to test, if the T-lymphocytes belong to the POZ or not. The results did not solve the question. But it has been confirmed that the POZ of the tissues are haematopoetic stem cells. Regarding to the obtained PO evidence nude mice are deranged in the PO-cell system. This derangement might be the reason for the fact that these animals tolerate foreign tissues like tumours.