Consequences of inter cellular molecular transfer in vitro and in vivo

Cell to cell interaction within the immune system takes place within the immunological synapse. As a consequence, surface molecules can be exchanged. We will use an antibody-directed toxin approach to deplete recipient cells that have acquired donor MHC class II molecules (and vice versa) to study their contribution towards the rejection process in a mouse kidney allograft model. An anti donor MHC class II antibody will be used to direct a 'toxin' (gelonin) towards cells that express donor class II MHC molecules. If the donor (but not recipient) cells are resistant to the toxin, then only recipient (Multi drug resistant gene knockout mice which are toxin sensitive) cells that have acquired donor class II MHC molecules will be lysed. This will enable us to determine the relative contribution of this process to the alloresponse. We have synthesized this immunotoxin and demonstrated its effectiveness both in vitro and in vivo. In vitro experiments will also be performed to investigate the ability of the phenomenon to link the direct and indirect antigen presentation pathways. Understanding the consequences of MHC transfer will also have important implications in other fields where antigen presentation is involved, such as tumor immunology, vaccination, infection and auto-immune diseases.

Cell to cell interaction within the immune system takes place within the immunological synapse. As a consequence, surface molecules can be exchanged. We will use an antibody-directed toxin approach to deplete recipient cells that have acquired donor MHC class II molecules (and vice versa) to study their contribution towards the rejection process in a mouse kidney allograft model. An anti donor MHC class II antibody will be used to direct a 'toxin' (gelonin) towards cells that express donor class II MHC molecules. If the donor (but not recipient) cells are resistant to the toxin, then only recipient (Multi drug resistant gene knockout mice which are toxin sensitive) cells that have acquired donor class II MHC molecules will be lysed. This will enable us to determine the relative contribution of this process to the alloresponse. We have synthesized this immunotoxin and demonstrated its effectiveness both in vitro and in vivo. In vitro experiments will also be performed to investigate the ability of the phenomenon to link the direct and indirect antigen presentation pathways. Understanding the consequences of MHC transfer will also have important implications in other fields where antigen presentation is involved, such as tumor immunology, vaccination, infection and auto-immune diseases.

In addition to the potential benefits to academia stated in the previous section, the proposed research may have impact in other ways: 1. Although exchange of cell surface molecules had been know for some time. However, despite research efforts in recent years, its functional consequence in a situation relevant to real life, as oppose to simulated in vitro settings, is still unknown. Models to study this had been lacking as it is not possible to stop intercellular molecular transfer in vivo. The experiments proposed here can address some of these questions that many had not been able to answer for a long time. 2. The model we have devised here using immunotoxin and animals that have enhanced sensitivity to the toxin is novel. We have already demonstrated its effectiveness and can be used in other areas of biomedical research to address different questions.