HB1.F3.eGFP cell movement and encirclement of U251.dsRed target cells.

Frames are excised from larger wide-field sequences taken at 30 min intervals. A, Approach and contact formation by one HB1.F3.eGFP cell (filled arrow) and progression of contact formation by another (open arrow). Stages of HB1.F3.eGFP cell (filled arrow) approach and contact formation were typical: extension of a leading process making contact with the U251.dsRed cell (3.5 h) followed by translocation of the cell body (5.0–7.0 h) and then envelopment of the glioma cell (7.5 h). The other HB1.F3.eGFP cell (open arrow), initially in contact with one of two adjacent U251.dsRed cells, over time extended forward and laterally to move off the surface of both cells. A third HB1.F3.eGFP cell (lower right, not marked) appeared to contact the U251.dsRed cell of interest to the second HB1.F3.eGFP cell, begin to move over the U251.dsRed cell surface (1.0–3.0 h), stall and regress (3.5–7.0 h), and then begin to advance at the end of the sequence (7.5 h). B, Process of HB1.F3.eGFP cell encirclement of an U251.dsRed.dsRed target. Lamellipodia extend from the initial contact site (1.0–3.0 h) over almost the entire surface of the U251.dsRed glioma cell (6.0–12.0 h) to eventually encircle the U251.dsRed cell. Scale bars  = 15 µm.