Viability and distribution of leukocytes following cross-circulation experiments between leukemic and normal or irradiated rats.

IN PREVIOUS STUI)IES imivolvimsg acute cross-circulat-ioms experiment-s in rats, evidence was obtained that leukocyt-es transfused by this method were not imnsediately destroyed. ‘ 2 It was postulated that disappearance of t-ramisfused leukocytes fromn the arterial blood of irradiated leukopenic animals represemsted redistribut-ioms of these cells into a depleted body leukocyte “pool,” rather than their dest-ructiomi amid lysis. Indirect evidemsce for functional viability of these cells was derived from t-he fact t-hat irradiated rats, aft-er cross-circulatiomi with normual aninsabs, demomistrated increased ability to remove bacteria from their blood, probably t-hrough the mechanisni of phagocytosis by the transfused henkocytes.3 Morphologic idemit-ificatiomi amid localizatiomi of transfused leukocytes after they had disappeared fromn the circulation should reveal their sites of redistributioti. It has t)eems postulated that msomscirculat-imig transfused leukocytes might retisaili viable cit-her its the tissues or within sluggish vascular channels. Although the method of cross-circulatiomi permitted transfer of 400,000,000 normal leukocytes ati(l eveis more leukenuic cells imito irradiated recipients, Osgood’s calculatioms would iti(hicat-e t-hat this quamitity probably represents only a smnall fraction of the total ratleukocyte “pool.” It seemed unlikely, then, that microscopic examimiation of the tissues would permitthe idemutification amid localization of the transfused cells. The umsique circulation of t-he rodeist t-ail suggested that the capillaries amid vemsubes of the tail mightbe a site of intravascular heukocyte aggregatiomi. Therefore, certain studies of the normal rat tail were umsdert-aken, aii(h tail blood leukocyt-e coumits were compared with arterial blood leukocyte counts duritsg and aft-er various cross-circubatioms experiments. Its addition to the observations relating to the viability of transfused leukocytes, sonic interesting aspects comscermsed with the transmission of the Shay chiorobeukemia amid with t-he ability of leukemnic leukocyt-es to reverse radiation damusage were emscoumstered.