The Effects of (99mTc) Hm-Pao Labeling on Lymphocyte Functions

Objective: (99mTc) HM-PAO labeled leucocytes have been used as a standard diagnostic procedure for the detection of\udinfection and inflammation. Although, some investigators have already pointed out that labeling of leucocytes with (99mTc)\udHM-PAO has detrimental effects on the cells, still very little is known regarding the effects of ionizing radiation on lymphocyte\udfunctions.\udMethods: In this study, we evaluated the effects of (99mTc) HM-PAO labeling on lymphocyte adhesion, proliferation,\udmigration and apoptosis. We used NC-NC lymphoblastoid cell line as the lymphocyte population. (99mTc) HM-PAO labeling\uddecreased cell adhesion, proliferation and motility whereas induced apoptosis, and cell cycle arrest. Proliferation assays were\udperformed both using MTT and ELISA tests with 24 hours intervals following labeling.\udResults: It was recorded that the rate of decrease in proliferation was up to 70% by the 4th day after labeling. (99mTc) HMPAO\udlabeling led a 35% decrease on adhesion ability of the cells on fibronectin. By using Boyden chamber motility assay, we\udshowed that both spontaneous and MCP-1 induced lymphocyte motility were potently blocked by (99mTc) HM-PAO labeling.\udThe rate of decrease in motility was approximately five times. In addition, we observed a 12 times increase in the apoptosis\udrate within the (99mTc) HM-PAO treated cells compared to the control cells. Besides it was observed that cell cycle arrest was\udinduced starting from 3rd day after (99mTc) HM-PAO treatment.\udConclusion: Based on our data (99mTc) HM-PAO labeling has damaging effects on lymphocyte functions including cell\udadhesion, proliferation, motility and viability in in vitr