Multivalent cross-linking of membrane Ig sensitizes murine B cells to a broader spectrum of CpG-containing oligodeoxynucleotide motifs, including their methylated counterparts, for stimulation of proliferation and Ig secretion

• Published in: International immunology 1999-10, Vol.11 (10), p.1693-1700
• Main Authors: Goeckeritz, Bruce E., Flora, Michael, Witherspoon, Kim, Vos, Quirijn, Lees, Andrew, Dennis, Gregory J., Pisetsky, David S., Klinman, Dennis M., Snapper, Clifford M., Mond, James J.
• Format: Article
• Language: English
• Subjects: Animals; anti-IgD–dex anti-IgD conjugated to high mol. wt dextran; antibodies; Antibodies - metabolism; Antibody Specificity; B lymphocytes; B-Lymphocytes - immunology; CD40L CD40 ligand; Cell Count; Cells, Cultured; cellular activation; CpG; CpG cytosine–guanine dinucleotide; Dextrans - metabolism; DNA Methylation; Enzyme-Linked Immunosorbent Assay; Female; Immunoglobulin D - immunology; Immunoglobulin G - analysis; Immunoglobulin M - analysis; Immunoglobulins - biosynthesis; LPS lipopolysaccharide; Lymphocyte Activation; Mice; Mice, Inbred Strains; ODN oligodeoxynucleotide; oligodeoxynucleotides; Receptors, Antigen, B-Cell - metabolism; rodent; SN supernatant; spleen; Spleen - cytology
• ISSN: 0953-8178; 1460-2377
• DOI: 10.1093/intimm/11.10.1693

We have previously reported that B cells that are activated by multivalent but not bivalent membrane Ig cross-linking ligands synergize with various B cell activators culminating in enhanced B cell proliferation. In this study we asked whether B cells that are activated by a multivalent mIg cross-linking agonist could respond to oligodeoxynucleotides (ODN) containing non-stimulatory motifs. Earlier reports have shown that ODN containing a CpG motif in which the cytosine is unmethylated and is flanked by two 5′ purines and two 3′ pyrimidines induce high levels of B cell activation, while ODN whose CpG are methylated or flanked by sequences other than the optimal two 5′ purines and two 3′ pyrimidines were non-stimulatory. In this manuscript we show that when B cells are stimulated in vitro with dextran-conjugated anti-IgD antibodies (anti-IgD–dex), as the multivalent mIg ligand, their proliferation is enhanced and they can be induced to secrete Ig in response to ODN containing various non-optimal motifs, both methylated and non-methylated. Furthermore we could induce synergistic levels of proliferation with concentrations of anti-IgD–dex that were in the picomolar concentration range and with concentrations of ODN that were 10- to 100-fold less than previously reported to be necessary for mitogenic activity. These data provided a model to explain how low concentrations of a multi-epitope-expressing microorganism in the context of mammalian (methylated) or microorganism (non-methylated) DNA can lead to dysregulated B cell proliferation and Ig secretion.