A new and simple method to study the role of soluble factors in antibody-mediated cell modulation.

This paper describes an in vitro method to study how interactions between cell suspensions incubated in two culture compartments can occur by diffusion of small molecules through a dialysis membrane. This consists of in vitro cultures of a human PBMC suspension, divided into two parts separated by a dialysis membrane. In one of the cultures, a mitogenic monoclonal antibody (mAb) is added. The porosity of the membrane permits cytokines secreted by activated cells to pass while blocking the antibodies. As a model, PBMC from the same blood donor were divided into two parts and one portion was incubated with an anti-CD3 monoclonal antibody (OKT3 Ortho-Cilag), known to induce IL-2 secretion whereas the other was enclosed in a dialysis bag without antibody. After a 4 day incubation, the cells incubated outside the bag proliferate and secrete cytokines which pass through the membrane and induce cell proliferation inside the bag. This method could complement the currently used methods for the analysis of antibody-mediated cell activation.