DEVELOPMENT OF A CELL-CULTURE SYSTEM TO STUDY ANTIBODY CONVECTION IN TUMORS

The convective transport of fluid and of a binding antibody through a cultured tumor cell layer was investigated with a mouse melanoma cell line (B16F10) grown on a microporous polycarbonate filter (Snapwell in serts). The inserts were precoated with Matrigel or collagen, or were uncoated, The cell layers were exposed to nominal pressure gradients f rom 5 to 25 cm H2O, and the volume flux was measured by collecting the effluent volume over time. The rate of convective transport of a bind ing monoclonal antibody that recognizes the murine transferrin recepto r (a-TfR) was investigated at a nominal pressure gradient of 15 cm H2O and compared with that of an isotype matched, nonbinding control, The resistance, R, of the cell layer to fluid flow was quantified as the hydraulic conductivity, L-p (= 1/R); the ability of the cell layer to retard antibody transport was quantified as the reflection coefficient , sigma. The resulting L-p values decreased with increasing cell densi ty, in a manner consistent with Poiseuille flow. Collagen or Matrigel precoating also decreased L-p values, with cells grown on Matrigel pro viding the greatest resistance. The sigma values were 0.67 (+/- 0.08) for the a-TfR antibody and 0.51 (+/- 0.06) for the control, indicating that the cell layer acts as a semipermeable barrier to convective tra nsport of antibody that is less permeable to the binding antibody.