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Human anti-pneumococci antibody produced by an Epstein Barr virus (EBV)-immortalized cell line
Abstract:
Anti-pneumococcal antibody-producing lymphocytes from a patient who was immunized with Pneumovax (a polysaccharide mixture from 14 different pneumococci types) were selected and immortalized with Epstein Barr virus (EBV). The cells of the emerging cloned line were shown on a single cell level assay to secrete an IgM, kappa anti-pneumococci antibody. This human monoclonal antibody bound specifically to polysaccharides of pneumococci type 8, but did not bind to any of the other 13 pneumococci types that were present in the Pneumovax mixture. In competition experiments, inhibition of binding occurred with polysaccharide type 8 and Pneumovax only. This diploid cell line has actively secreted the specific antibody (2.8 micrograms/10(6) cells/ml) now for more than 9 mo. In patients, increased anti-pneumococcal antibody titers generated by active immunization with Pneumovax improves resistance to the corresponding bacterial infection. Production in vitro of human monoclonal antibodies directed toward bacterial and viral antigens enables a new possible approach for passive immune protection.
Insights
Researchers developed a human monoclonal antibody targeting specific pneumococcal bacteria. This breakthrough offers a new avenue for passive immune protection against pneumococcal infections.
Area of Science:
- Immunology
- Microbiology
Background:
- Active immunization with Pneumovax enhances resistance to pneumococcal infections.
- Human monoclonal antibodies against bacterial antigens represent a novel approach for passive immunity.
Purpose of the Study:
- To generate and characterize a human monoclonal antibody against Streptococcus pneumoniae.
- To explore the potential of in vitro antibody production for passive immune protection.
Main Methods:
- Selected and immortalized anti-pneumococcal antibody-producing lymphocytes using Epstein-Barr virus (EBV).
- Assessed antibody secretion and specificity of the cloned cell line using single-cell level assays and competition experiments.
Main Results:
- A human monoclonal antibody (IgM, kappa) specific for Streptococcus pneumoniae type 8 polysaccharide was produced.
- The antibody was secreted by a diploid cell line for over 9 months.
- Binding specificity was confirmed against type 8 polysaccharide and Pneumovax, with no cross-reactivity to other types.
Conclusions:
- Successfully produced a specific human monoclonal antibody against Streptococcus pneumoniae type 8 in vitro.
- This demonstrates a viable method for generating human monoclonal antibodies for potential therapeutic use.
- In vitro production of specific antibodies offers a promising strategy for passive immune protection against bacterial infections.