Patent ID: 7175848

Claim:
A method of eliciting an immune response to ricin A chain, comprising the steps of: a) obtaining an altered ricin A chain having an amino acid sequence that has been altered relative to a ricin A chain toxin sequence of SEQ ID NO: 1, to comprise: i) a mutation in at least one of L74, D75, and V76, wherein said altered ricin A chain has reduced ability to cause vascular leak syndrome relative to ricin A chain toxin, and ii) a mutation in at least one of Y80, Y123, E177, R180, N209, and W211, wherein said altered ricin A chain has reduced or absent catalytic activity; and b) contacting said altered ricin A chain with an animal in an amount sufficient to elicit an immune response to ricin A chain toxin, wherein an immune response to ricin A chain toxin is elicited in said animal.