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Generation of Discriminative Human Monoclonal Antibodies from Rare Antigen-specific B Cells Circulating in Blood
Published on: February 6, 2018
Low affinity binding of mouse immunoglobulin to human CD5+ B cells
1Immunobiology Unit, University of Technology, Sydney, NSW, Australia.
Immunology and Cell Biology
|August 1, 1991
Summary
CD5-bearing B cells in chronic lymphocytic leukemia (CLL) express polyreactive immunoglobulin (Ig) on their surface. This Ig binds broadly to antigens through a mechanism independent of the antigen-binding site, suggesting a unique interaction pathway.
Area of Science:
- Immunology
- Cell Biology
- Hematology
Background:
- Polyreactive immunoglobulin (Ig) from CD5-bearing B cells can bind diverse antigens.
- Chronic lymphocytic leukemia (CLL) is characterized by CD5-positive B cells.
Purpose of the Study:
- To investigate the low-affinity binding of mouse Ig molecules to CD5-bearing B cells in CLL.
- To elucidate the mechanism and binding sites involved in this interaction.
Main Methods:
- Flow cytometry was employed to detect Ig binding to B cells.
- Fab and F(ab')2 fragments were used to differentiate binding mechanisms.
- Blocking studies were performed to identify involved cell surface molecules.
Main Results:
- Mouse Ig isotypes (G, A, M) and IgG subclasses bound to CLL B cells.
- Binding occurred independently of the Ig antigen-binding site and Fc receptors.
- Low-affinity binding was attributed to interactions with surface IgM and surface IgD (sIgM/sIgD).
Conclusions:
- CD5-bearing B cells in CLL express polyreactive Ig on their surface.
- The binding mechanism involves surface Ig receptors, not the antigen-binding site.
- This finding provides insight into the nature of Ig expressed in CLL.
