Open Access Research article

Generation of potent neutralizing human monoclonal antibodies against cytomegalovirus infection from immune B cells

Ada Funaro12*, Giorgio Gribaudo3, Anna Luganini3, Erika Ortolan12, Nicola Lo Buono1, Elisa Vicenzi4, Luca Cassetta4, Santo Landolfo3, Richard Buick5, Luca Falciola6, Marianne Murphy6, Gianni Garotta6 and Fabio Malavasi12

Author Affiliations

1 Department of Genetics, Biology and Biochemistry, University of Torino Medical School, Via Santena 19, 10126 Torino, Italy

2 Research Center on Experimental Medicine (CeRMS), University of Torino Medical School, Via Santena 19, 10126 Torino, Italy

3 Department of Public Health and Microbiology, University of Torino, Via Santena 9, 10126 Torino, Italy

4 Viral Pathogens and Biosafety Unit, DIBIT-San Raffaele Scientific Institute, Via Olgettina 58, 20123 Milano, Italy

5 Fusion Antibodies Ltd, Pembroke Loop Road, Dunmurry, Belfast, BT17 0QL, Northern Ireland

6 RiboVax Biotechnologies, 12 Avenue des Morgines, 1213 Petit-Lancy, Geneva, Switzerland

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BMC Biotechnology 2008, 8:85  doi:10.1186/1472-6750-8-85

Published: 12 November 2008

Abstract

Background

Human monoclonal antibodies (mAbs) generated as a result of the immune response are likely to be the most effective therapeutic antibodies, particularly in the case of infectious diseases against which the immune response is protective.

Human cytomegalovirus (HCMV) is an ubiquitous opportunistic virus that is the most serious pathogenic agent in transplant patients. The available therapeutic armamentarium (e.g. HCMV hyperimmune globulins or antivirals) is associated with severe side effects and the emergence of drug-resistant strains; therefore, neutralizing human mAb may be a decisive alternative in the prevention of primary and re-activated HCMV infections in these patients.

Results

The purpose of this study was to generate neutralizing mAb against HCMV from the immunological repertoire of immune donors. To this aim, we designed an efficient technology relying on two discrete and sequential steps: first, human B-lymphocytes are stimulated with TLR9-agonists and IL-2; second, after both additives are removed, the cells are infected with EBV. Using this strategy we obtained 29 clones secreting IgG neutralizing the HCMV infectivity; four among these were further characterized. All of the mAbs neutralize the infection in different combinations of HCMV strains and target cells, with a potency ~20 fold higher than that of the HCMV hyperimmune globulins, currently used in transplant recipients. Recombinant human monoclonal IgG1 suitable as a prophylactic or therapeutic tool in clinical applications has been generated.

Conclusion

The technology described has proven to be more reproducible, efficient and rapid than previously reported techniques, and can be adopted at low overall costs by any cell biology laboratory for the development of fully human mAbs for immunotherapeutic uses.