Antigen presentation by liposomes as model system for T-B cell interaction.

Using the earlier established liposome system for antigen presentation, in which liposomes bearing major histocompatibility complex (MHC)-class II molecules inserted into and protein antigen covalently linked to the membrane were found to be sufficient for an antigen-specific and MHC-restricted activation of T cells, the minimal requirements for T-B cell interaction were investigated. Liposomes carrying MHC class II molecules and antigen-specific monoclonal antibodies were constructed and tested for their ability to present soluble antigen to T cells. With the antigens lactate dehydrogenase B and pigeon cytochrome c, a specific stimulation of T cell clones and hybridomas could be obtained. These results demonstrate the possibility of a direct involvement of the immunoglobulins on the B cell surface in their interaction with T cells.