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|Title:||The High Affinity Anti-Fluorescyl Immunoglobulin-M Response in Rabbits|
|Author(s):||Holzman, Rita Brewer|
|Department / Program:||Microbiology|
|Degree Granting Institution:||University of Illinois at Urbana-Champaign|
|Abstract:||Studies were initiated to determine the inducibility of high affinity IgM populations in the fluorescein hapten system. Fluorescein has characteristically elicited IgG antibodies of relatively higher affinity than values observed with other hapten systems. Characterization of protein-ligand interactions, solvent effects and the microenvironment of induced IgM antibody was feasible due to the spectral properties of fluorescein.
High affinity IgM binding sites were characterized and compared with similarly high affinity IgG antibodies. While spectral, fluorescence and binding studies yielded comparable data for IgM and high affinity IgG populations, circular dichroic scans indicated that the active sites of the two immunoglobulin classes differed significantly.
Temporal studies, spanning an interval of one year, indicated that liganded IgM subpopulations were present throughout the immune response in relatively constant concentrations, and demonstrated a restricted range of Ka values (1-3 x 10('10) M('-1)) as well as relatively homogeneous heterogeneity indices. High affinity IgM populations did not exhibit the classical and well defined increases in affinity with time observed for IgG antibodies. Results indicated that liganded IgM subpopulations represented a limited number of high affinity IgM clones which lie significantly outside the distribution of predominantly low affinity IgM clones. The IgM population appeared to exhibit a biphasic, rather than Gaussian distribution, which has generally characterized IgG responses.
Idiotypic studies of liganded anti-fluorescyl IgM failed to determine whether high affinity IgM antibodies represented a germ line or somatic mutation product elicited by high affinity clones. The autoidiotypic response appeared to be more restricted than the isologous response, and demonstrated cross-reactivity between liganded IgM and IgG populations. Studies utilizing an affinity labeled idiotype indicated that anti-idiotypic antibodies recognized both free and active site bound fluorescein. This phenomenon probably correlated with the site-filling properties of the fluorescyl moiety.
Thesis (Ph.D.)--University of Illinois at Urbana-Champaign, 1981.
|Date Available in IDEALS:||2014-12-16|