Research article

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

Ada Funaro^1,2 , Giorgio Gribaudo³ , Anna Luganini³ , Erika Ortolan^1,2 , Nicola Lo Buono¹ , Elisa Vicenzi⁴ , Luca Cassetta⁴ , Santo Landolfo³ , Richard Buick⁵ , Luca Falciola⁶ , Marianne Murphy⁶ , Gianni Garotta⁶ and Fabio Malavasi^1,2

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

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

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

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

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

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

author email corresponding author email

BMC Biotechnology 2008, 8:85doi: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.