Sensitive and quantitative determination of monocyte adherence.

A new sensitive and highly reproducible one-step ELISA is described to quantitatively determine the adherent capacity of monocytes and related cell lines. Cells were labelled with a monoclonal antibody/peroxidase conjugate which did not affect the adhesive properties of these cells. The labelled cells were allowed to adhere for 1 h and subsequently stained by the addition of substrate. The results demonstrate that there is a good correlation between the number of peroxidase-labelled adherent cells and the absorbance measured at 450 nm. Furthermore the assay permits the use of very low cell numbers since adherent cells could be measured efficiently at a level of only 100-500 cells/well. The method may be very useful in the selection of hybridomas that secrete antibodies which inhibit adherence of cells. In addition it can be applied to study the adhesive properties of any cell type, provided that appropriate monoclonal antibodies are available.