A new approach to labeling cells with technetium-99m, Part I. Preparation of modified polylysine and in vitro cell labeling.
A method for labeling cells with technetium-99m via hydrophilic, polycationic poly D-lysine modified by N-acetyl homocysteine has been developed. The modified polylysine (MPL) is labeled with 99mTc in > 95% yield and is stable for > 12 h. Maximum cell labeling is achieved by a 1-h incubation at room temperature with isolated leukocytes, granulocytes and peripheral blood mononuclear cells attaining 60-75% 99mTc incorporation, and red blood cells 35%. Ninety-two percent of the label is retained by leukocytes after a 1-h incubation at room temperature in 50% serum. The cell uptake of 99mTc-MPL is affected by the presence of negatively charged species in the medium; the inhibitory effects of 5% serum or serum albumin can be reversed by increasing the concentration of 99mTc-MPL, while those of heparin are not.
Mahmood
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A
Department of Radiology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA USA.
Delmon-Moingeon
L I
LI
Limpa-Amara
N
N
Davison
A
A
Jones
A G
AG
D000328:Adult; D001773:Blood Cells / Q000000981:diagnostic imaging*; D004912:Erythrocytes / Q000000981:diagnostic imaging; D006098:Granulocytes / Q000000981:diagnostic imaging; D006801:Humans; D006863:Hydrogen-Ion Concentration; D066298:In Vitro Techniques; D007553:Isotope Labeling; D008297:Male; D009000:Monocytes / Q000000981:diagnostic imaging; D015609:Organotechnetium Compounds / Q000138:chemical synthesis*; D011107:Polylysine / Q000138:chemical synthesis*; D011877:Radionuclide Imaging; D013696:Temperature
D015609:Organotechnetium Compounds; C094942:technetium Tc 99m polylysine; D011107:Polylysine