Enrichment of IgG anti-DNA-producing lymphoblastoid cell lines by antigen-coated immunomagnetic beads.
In this paper we describe the establishment of four anti-DNA-producing lymphoblastoid cell lines (LCL) by Epstein-Barr virus (EBV) infection of peripheral blood B-cells from a patient with systemic lupus erythematosus. The LCL showed a heterogeneous cell composition: the frequencies of cells in active proliferation, cells secreting IgG or IgM, and cells effectively producing IgG or IgM anti-DNA were estimated by limiting dilution analysis. The cells producing anti-DNA antibodies were a small fraction of the whole cell population constituting the LCL. In order to enrich the fraction of cells producing the desired antibody we performed a positive selection by DNA-coated immunomagnetic beads. Results show that in two out of three IgG anti-DNA-secreting LCL the frequency of DNA-producing cells increased after incubation with DNA-coated beads. At variance, IgM anti-DNA-secreting cells were completely lost after immunomagnetic separation. This approach could represent a further tool to obtain better fusion partners to construct stable hybrids secreting human monoclonal antibodies. The advantages of the presented technique would be: (a) removing of the fraction of low-affinity IgM-producing cells, which is often prevalent in EBV-induced LCL; and (b) the enrichment of IgG anti-DNA producing cells, which better represent the antibodies involved in the pathogenesis of the disease.
Barcellini
W
W
Istituto di Medicina Interna, Malattie Infettive e Immunopatologia, University of Milan, Italy.
Borghi
M O
MO
Fain
C
C
Del Papa
N
N
Nicoletti
F
F
Meroni
P L
PL
D000328:Adult; D000974:Antibodies, Antinuclear / Q000276:immunology*; D000917:Antibody Formation; D000921:Antibody-Producing Cells / Q000166:cytology; D000941:Antigens; D001402:B-Lymphocytes / Q000382:microbiology; D002460:Cell Line; D002469:Cell Separation / Q000379:methods; D005260:Female; D006566:Herpesviridae Infections; D004854:Herpesvirus 4, Human; D006801:Humans; D008280:Magnetics; D008863:Microspheres
D000974:Antibodies, Antinuclear; D000941:Antigens