Patent ID: 7794728

Claim:
An attenuated Listeria bacterium having an inactivating mutation in a lipoate protein ligase (IpIA) gene having SEQ ID NO:44 and a mutation in a lysteriolysin O (hly) gene having SEQ ID NO:43, wherein said mutation in said hly gene is not a deletion mutation that removes said hly gene's entire PEST sequence coding domain found in the N-terminal 75 residues of the LLO protein, and wherein said mutation in said hly gene is in a coding region of said hly gene and said mutated hly gene encodes an LLO protein that is at least two-fold more hemolytic at neutral pH than wild-type LLO having SEQ ID NO:43; wherein said mutation is at a codon encoding amino acid residue 44 or 461 of a wild type Listeria monocytogenes LLO protein being encoded by said hly gene having SEQ ID NO:43.