The use of technetium-99m as a radioisotopic label to assess cell-mediated immunity in vitro☆☆☆

摘要: Abstract We have developed a radioisotopic microassay of cell-mediated immunity employing target cells prelabeled with technetium-99m ( 99m Tc), high specific activity metastable gamma emitter. Labeling kinetics, release and reutilization, subcellular localization, effects Tc on DNA protein synthesis been investigated. Target were optimally labeled 10 mCi at 37 °C for min. Cyclic freezing thawing released less than 10% total bound radioisotope. Spontaneous leakage by monolayer was negligible over 48 hr that which appeared to be nonreutilizable. Cell fractionation revealed nuclear, mitochondrial, microsomal fractions all Tc. The incorporation 3 H-thymidine H-amino acids not impaired in Tc-labeled cells. alloimmune reactivity C57BL/6 mice had received A/J skin allografts studied means the microcytotoxicity assay. Cell-mediated clearly evident 7 days postgrafting, peaked 14 days, declined background levels 21 days. These findings correlated well initial acceptance ultimate rejection allografts. rapid labeling time without dependence upon cell division incorporation, activity, low spontaneous release, nonreutilizability are important advantages other radionuclides employed vitro assays immunity.