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.
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.
Goeckeritz
B E
BE
Departments of Medicine and Pathology, and Biomedical Instrumentation Center, Uniformed Services University of the Health Sciences, Bethesda, MD 20814-4799, USA.
Flora
M
M
Witherspoon
K
K
Vos
Q
Q
Lees
A
A
Dennis
G J
GJ
Pisetsky
D S
DS
Klinman
D M
DM
Snapper
C M
CM
Mond
J J
JJ
D000818:Animals; D000906:Antibodies / Q000378:metabolism; D000918:Antibody Specificity; D001402:B-Lymphocytes / Q000276:immunology*; D002452:Cell Count; D002478:Cells, Cultured; D019175:DNA Methylation; D003911:Dextrans / Q000378:metabolism; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D007072:Immunoglobulin D / Q000276:immunology; D007074:Immunoglobulin G / Q000032:analysis; D007075:Immunoglobulin M / Q000032:analysis; D007136:Immunoglobulins / Q000096:biosynthesis*; D008213:Lymphocyte Activation; D051379:Mice; D008815:Mice, Inbred Strains; D011947:Receptors, Antigen, B-Cell / Q000378:metabolism*; D013154:Spleen / Q000166:cytology
D000906:Antibodies; D003911:Dextrans; D007072:Immunoglobulin D; D007074:Immunoglobulin G; D007075:Immunoglobulin M; D007136:Immunoglobulins; D011947:Receptors, Antigen, B-Cell