Tumor-infiltrating B lymphocytes as an efficient source of highly specific immunoglobulins recognizing tumor cells

Emiliano Pavoni¹ , Giorgia Monteriù¹ , Daniela Santapaola¹ , Fiorella Petronzelli² , Anna Maria Anastasi² , Angela Pelliccia² , Valeria D'Alessio² , Rita De Santis² and Olga Minenkova¹

¹Kenton Srl, c/o Sigma-Tau SpA, via Pontina, km 30.400, 00040 Pomezia (RM), Italy

²Immunology Department, Sigma-Tau SpA, via Pontina, km 30.400, 00040 Pomezia (RM), Italy

author email corresponding author email

BMC Biotechnology 2007, 7:70doi:10.1186/1472-6750-7-70


Published:	18 October 2007

Abstract

Background

There is much evidence that tumor cells elicit a humoral immune response in patients. In most cases, the presence of antibodies in peripheral blood is detected only in small proportion of patients with tumors overexpressing the corresponding antigen. In the present study, we analyzed the significance of local humoral response provided by tumor-infiltrating lymphocytes in breast cancer patients.

Methods

The ability of a patient's immune system to produce specific antibodies inside tumor tissue, capable of recognizing tumor cells, was explored through analysis of the oligoclonality of antibodies derived from tumor-infiltrating lymphocytes and construction of a series of recombinant antibody libraries in scFv format, derived from breast tumor-infiltrating B lymphocytes. These libraries and one from peripheral blood lymphocytes of a single breast cancer patient were panned against three purified surface tumor antigens, such as CEA, MUC1 and ED-B domain, and against intact MCF7 breast carcinoma cells.

Results

Application of novel display vector, pKM19, allowed isolation of a large panel of breast cancer-specific antibodies against known tumor antigens, as well as against breast carcinoma cells. Reactivity of novel scFvs was confirmed by ELISA, immunohistochemistry, fluorescence staining and flow cytometry. We demonstrated that seven of ten primary breast tumor specimens, obtained using discarded surgical material, could be exploited as an appropriate source for generation of phage display libraries, giving highly specific antitumor antibodies which recognize heterologous tumor cells.

Conclusion

Local humoral immune response within tumor tissue in breast cancer patients frequently has an oligoclonal character. Efficient selection of specific antitumor antibodies from recombinant antibody libraries, derived from such oligoclonal tumor-infiltrated B lymphocytes, indicates the presence of natural immune response against tumor antigens in these patients. The described method is very promising for development of antitumor antibodies, potentially useful for diagnostic and therapeutic approaches.