Influence of Serum Dental Alloy Eluates on Primary Human CD8±Lymphocyte-Migration

Introduction: Active cellular locomotion is a feature of diverse T cell types. Using a 3-D collagen matrix migration model in combination with computer-assisted cell tracking for reconstruction of migration paths and confocal microscopy, we investigated the locomotion behavior of CD8+ lymphocytes governing cell-dental material interactions due to the influence of different dental alloys. Material and methods: Locomotion of immunomagnetically isolated human CD8+ peripheral blood lymphocytes suspended in type I collagen gels was recorded using time-lapse videomicroscopy. Paths of randomly selected locomoting cells over a period of two hours were digitized, reconstructed and quantitatively analysed. A dental alloy free assay served as a control. We evaluated two different quantitative parameters: (1) the average percentage of CD8+ cells moving and (2) the velocity of the migrating CD8±cells due to the influence of serum-alloy-eluates. Results: We could show a reduction of average percentage of CD8+ cells migration in the presence of alloys (range from 13% up to 19,6%) in comparison to the average migration of 33% in the control. Concerning the velocity the same deminishing tendency could be seen (range from 3,8µm/min up to 2,4 µm/min for alloys, 6,3µm/min for controls). Discussion: We presume that the CD8+ cells are migrating in a 3-D collagen matrix migration model in a 'random-walk' fashion influenced by the components of serum-alloy-eluates. Recent studies (Entschladen et al. 1997) showed a spontaneous locomotion of CD8+ cells accompanied by enhanced tyrosine phosphorylation of the focal adhesion kinase (FAK). In contrast inhibition of protein tyrosine kinase (PTK) activity was overcome by subsequent activation of protein kinase C (PKC) using PMA. This PKC-driven locomotion is independent of tyrosine phosphorylation events indicating that the T lymphocyte locomotion is regulated by more than one signal transduction pathway. The analysis of these two 'driven-mechanisms' could be used as an indicator for biocompatibility of different dental materials. Supported by Heraeus-Kulzer Keywords: T-lymphocytes, Migration, dental alloy, Elution, Confocal Laser Scanning Microscopy (CLSM)