Patent Evaluation: Cellular immunity vaccines from bacterial toxin-antigen conjugates

Summary

Novelty: A hybrid protein is claimed comprising a modified bacterial toxin that has a translocating domain and a polypeptide or protein that is exogenous to an antigen-presenting cell. The hybrid protein is capable of eliciting an immune response by cytotoxic lymphocytes. The preparation of vaccines comprising the protein against influenza, AIDS, human papilloma virus, cytomegalovirus, Epstein-Barr virus, Rota virus or respiratory syncytial virus is claimed.

Biology: Cytotoxic T-lymphocyte activity against U-2 OS cells sensitized with a hybrid of Pseudomonas exotoxin (PE) and the influenza Ma sequence is described and results are presented graphically. The binding ability of PEMa to the PE receptor on U-2 OS cells was measured. PEMa was shown to compete with PE and to protect cells from its toxic effects suggesting that sensitization is through PE receptor-mediated uptake and processing.

Chemistry: Full recombinant and experimental details are provided. Preferably the protein comprises PE modified by deletion of structural domain III and a viral polypeptide selected from influenza virus matrix protein, residues 57–68 of the matrix protein, nucleoprotein or the GAG protein of HIV-1.