Patent ID: 7014998

Claim:
A method for screening for an agent useful in promoting immunosuppression or immunologic tolerance in a mammal comprising: (a) administering a test agent to an experimental animal; (b) obtaining a biological sample comprising T-cells from the animal and a sample from a control animal of the same species; (c) examining CTLA-4 expression on both the T-cells obtained from the experimental animal to which the test agent has been administered and the T-cells obtained from the control animal, by measuring the levels of at least one of cell surface CTLA-4, cytoplasmic CTLA-4, or CTLA-4 mRNA in the T-cells, and comparing the levels of CTLA-4 on the T-cells in the control and experimental animals; (d) examining T-cell activation by measuring T-cell activation in the T-cells obtained from the experimental animal to which the test agent has been administered, by measuring upregulation of T-cell markers, T-cell proliferation, and entry of T-cells into cell cycle; and (e) identifying whether the administered test agent can be used to promote immunosuppression or immunologic tolerance in a mammal by determining if the administered test agent increases levels of CTLA-4 on T-cells in the sample from the experimental animal as compared to the levels of CTLA-4 on T-cells in the control animal sample; wherein the increase of CTLA-4 on the T-cells in the experimental sample occurs without observing T-cell activation.