title: Ex-vivo clonally expanded B lymphocytes infiltrating colorectal carcinoma are of mature immunophenotype and produce functional IgG.
abstract: BACKGROUND
  Tumor infiltrating B cells (TiBc) have not yet been investigated in detail. This may at least in part be due to technical difficulties. Here we describe a straightforward and reproducible method to isolate and culture TiBc from primary colorectal carcinomas (CRC).
  
  
  RESULTS
  TiBc cultures were generated by Epstein-Barr virus (EBV) immortalization. With this method, monoclonal TiBc cultures were obtained for 14/19 CRCs. As assessed by flow cytometry and ELISA, TiBc showed an activated immunophenotype (CD23(+), CD80(+)) and produced immunoglobulin (Ig; IgG secretion in 55% of the cultures). In functional in vitro analysis, most of the IgGs specifically bound to allogeneic CRC target cells. These data suggest that TiBc are antigen-experienced and thus may exhibit functionality in situ. Additionally, mini-cultures generated from 12 further CRCs revealed TiBc outgrowth exclusively in the presence of EBV.
  
  
  CONCLUSIONS
  In summary, this simple method provides a cellular tool and our data set the stage for analysing the bivalent role of TiBc; being antigen-presenting cells on the one hand and tumor-specific antibody producers on the other. Additionally, the generation of long-term TiBc cultures and their monoclonal Ig may serve to identify novel tumor-specific antigens.
authors.affiliation: Division of Molecular Oncology and Immunotherapy, Department of General Surgery, University of Rostock, Rostock, Germany.
authors.forename: Claudia
authors.initials: C
authors.lastname: Maletzki
authors.forename: Annika
authors.initials: A
authors.lastname: Jahnke
authors.forename: Christiane
authors.initials: C
authors.lastname: Ostwald
authors.forename: Ernst
authors.initials: E
authors.lastname: Klar
authors.forename: Friedrich
authors.initials: F
authors.lastname: Prall
authors.forename: Michael
authors.initials: M
authors.lastname: Linnebacher
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D018941:Antigens, CD19 / Q000096:biosynthesis; D018951:Antigens, CD20 / Q000096:biosynthesis; D001402:B-Lymphocytes / Q000378:metabolism*; D018122:B7-1 Antigen / Q000096:biosynthesis; D015179:Colorectal Neoplasms / Q000276:immunology / Q000378:metabolism*; D004797:Enzyme-Linked Immunosorbent Assay / Q000379:methods; D005260:Female; D005434:Flow Cytometry / Q000379:methods; D004854:Herpesvirus 4, Human / Q000378:metabolism; D006801:Humans; D007074:Immunoglobulin G / Q000737:chemistry*; D007136:Immunoglobulins / Q000737:chemistry; D016130:Immunophenotyping / Q000379:methods*; D008297:Male; D008875:Middle Aged; D017455:Receptors, IgE / Q000096:biosynthesis; D015203:Reproducibility of Results
chemical_list: D018941:Antigens, CD19; D018951:Antigens, CD20; D018122:B7-1 Antigen; D007074:Immunoglobulin G; D007136:Immunoglobulins; D017455:Receptors, IgE