Activation of Human B Lymphocytes by Nanogram Concentrations of Anti- IgM-Dextran Conjugates
Abstract
Surface immunoglobulin (sIg) cross-linking on B lymphocytes by high concentrations of anti-Ig antibody has been used to mimic antigen-stimulated B cell activation. In order to develop a system to study sIg-medicated T cell- independent B cell activation using low concentrations of antigen that are achieved under in vivo conditions, we conjugated monoclonal anti-human IgM antibody (anti-mu) to dextran (molecular weight 2 x 10 to the sixth power) thereby increasing its valency. This dextran conjugate (anti-mu-Dex) simulated comparable levels of thymidine incorporation and B cell size increases as were seen with unconjugated anti-mu but at 100- to 1000-fold lower concentrations. Anti-mu-dex also simulated increases in intracellular ionized calcium (Ca to the second power +i) in a higher percentage of cells, of greater magnitude and of longer duration than that stimulated by unconjugated anti-mu. Interestingly, there was no direct correlation between the increases in Ca to the second power+i that were simulated by anti-mu-Dex and its ability to simulate B cell proliferation. The concentrations of anti-mu-Dex (10ug/ml) that led to the highest increase in Ca to the second power +i resulted in thymidine incorporation that was no greater than that of medium control, whereas 0.01 to 0.1 mug/ml stimulated significant thymidine incorporation with 50% lower levels of stimulation of Ca to hte second power +i. These data demonstrate that anti-mu-Dex is a potent activator of human B lymphocytes.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jan 01, 1990
- Accession Number
- ADA230045
Entities
People
- Carl H. June
- Gregory T. Rehe
- Ildy M. Katona
- Larry M. Wahl
- Mark Brunswick
Organizations
- Naval Medical Research Center