title: Studies on the regulation of igm immune response. VII. changes in the affinity of antibodies and cell receptors after immunization with the T-cell independent antigen DNP-Ficoll.
abstract: A/J-mice immunized by a single injection with DNP21-Ficoll respond on the humoral level exclusively with IgM antibodies. The intrinsic association constants (K0) of IgM anti-DNP to monovalent hapten E-DNP-L-lysine are within the range of 105-106 M-1 and do not change significantly during the immune response. On the other hand, the functional association constants (KF) of pentameric IgM to multivalent DNP-T4 bacteriophage increase from 1010 M-1 at 3rd day up to 1012 M-1 at 8th day. Subsequently, a decrease of KF to 1011 M-1 can be observed. This rise and fall of the affinity of IgM antibodies of multivalent DNP-conjugate can be detected at the cellular level also by inhibition of plaque formation. The concentration of DNP15-BSA needed for 50% inhibition of plaque formation (I50) decreases from second day to 8 th day by 4 orders, which represents a strong increase of functional affinity. In contrast, the I50 of E-DNP-L-lysine slightly decreases only until day 4 and does not change until day 21. the inhibition of rosette formation by mono- and multivalent ligands was used to study the affinity of lymphocyte receptors. In the course of immunization antigen-binding cells carrying receptors with increasingly higher affinity for multivalent DNP-conjugates occur. These results are discussed with regard to the importance of functional affinity of lymphocyte receptors for the antigen-driven selection of high affinity anti-DNP-cell clones producing IgM antibodies.
mesh_terms: D000818:Animals; D000915:Antibody Affinity; D000921:Antibody-Producing Cells / Q000276:immunology; D004136:Dinitrobenzenes / Q000276:immunology*; D005362:Ficoll / Q000276:immunology*; D006241:Haptens / Q000276:immunology*; D007075:Immunoglobulin M / Q000276:immunology*; D008239:Lysine / Q000276:immunology; D008297:Male; D051379:Mice; D009578:Nitrobenzenes / Q000276:immunology*; D011134:Polysaccharides / Q000276:immunology*; D011946:Receptors, Antigen / Q000276:immunology*; D013154:Spleen / Q000166:cytology
chemical_list: D004136:Dinitrobenzenes; D006241:Haptens; D007075:Immunoglobulin M; D009578:Nitrobenzenes; D011134:Polysaccharides; D011946:Receptors, Antigen; D005362:Ficoll; D008239:Lysine