On the interaction between protein L and immunoglobulins of various mammalian species

Research output: Contribution to journalArticle


Protein L, a cell wall molecule of certain strains of the anaerobic bacterial species Peptostreptococcus magnus, shows high affinity for human immunoglobulin (Ig) light chains. In the present study protein L was tested against a panel of human myeloma proteins of the IgG, IgM, IgA and IgE classes, and strong binding was seen with antibodies carrying kappa light chains. A high degree of specificity for Ig was demonstrated in binding experiments with human plasma proteins. Apart from human Ig, strong protein L-binding activity was also detected in the serum of 12 out of 23 tested additional mammalian species, including other primates and rodents. Subsequent analysis with purified Ig samples demonstrated the binding of protein L to Ig of important laboratory animal species such as the mouse, the rat and the rabbit. The affinity constants for the interactions between protein L and polyclonal IgG of these species were 2.6 x 10(9), 3.9 x 10(8) and 7.4 x 10(7), respectively. In non-human species, the binding of protein L was also found to be mediated through Ig light chains, and the results demonstrate the potential value of protein L as an immunochemical tool.


External organisations
  • Lund University
  • Karolinska Institutet
Research areas and keywords

Subject classification (UKÄ) – MANDATORY

  • Medical and Health Sciences


  • Animals, Bacterial Proteins, Binding Sites, Blood Proteins, Goats, Humans, Immunoglobulin Light Chains, Immunoglobulin kappa-Chains, Mice, Nerve Tissue Proteins, Peptostreptococcus, Rabbits, Rats, Species Specificity, Comparative Study, Journal Article, Research Support, Non-U.S. Gov't
Original languageEnglish
Pages (from-to)399-405
Number of pages7
JournalScandinavian Journal of Immunology
Issue number4
Publication statusPublished - 1993 Apr
Publication categoryResearch