Cells activated for wound repair have the potential to direct collective invasion of an epithelium.

Mechanisms regulating how groups of cells are signaled to move collectively from their original site and invade surrounding matrix are poorly understood. Here we develop a clinically relevant ex vivo injury invasion model to determine whether cells involved in directing wound healing have invasive function and whether they can act as leader cells to direct movement of a wounded epithelium through a three-dimensional (3D) extracellular matrix (ECM) environment. Similar to cancer invasion, we found that the injured cells invade into the ECM as cords, involving heterotypical cell-cell interactions. Mesenchymal cells with properties of activated repair cells that typically locate to a wound edge are present in leader positions at the front of ZO-1-rich invading cords of cells, where they extend vimentin intermediate filament-enriched protrusions into the 3D ECM. Injury-induced invasion depends on both vimentin cytoskeletal function and MMP-2/9 matrix remodeling, because inhibiting either of these suppressed invasion. Potential push and pull forces at the tips of the invading cords were revealed by time-lapse imaging, which showed cells actively extending and retracting protrusions into the ECM. This 3D injury invasion model can be used to investigate mechanisms of leader cell-directed invasion and understand how mechanisms of wound healing are hijacked to cause disease

A Binding Potency Assay for Pritumumab and Ecto-Domain Vimentin.

Pritumumab, a natural human IgG1kappa mAb, was isolated from the regional lymph node of a patient with cervical cancer. This antibody has been reported to bind the cytoskeletal protein vimentin, and to cell surface expressed vimentin referred to as ecto-domain vimentin (EDV). Here, we report details of the development of a potency of binding assay for pritumumab as a prerequisite before pursuing clinical trials. The enzyme linked immunosorbent assay (ELISA) to detect antibody-binding antigen can serve as a potency assay for release of manufactured samples to be used in clinical studies. Several layers of controls for this assay along with suitability testing for reagents and components of the assay must be developed before the assay can be incorporated for stability testing and release of manufatured samples