TWENTY-FIFTH ANNUAL EASTERN FISH HEALTH WORKSHOP MARCH 10-13, 2000          Affinity Maturation Of Trout Antibodies In Response To A Defined Antigen And A Viral Antigen(s)       Stephen L. Kaattari, Haili L. Zhang, Teresa D. Lewis, Ing Wei Khor, E. Alanna MacIntyre and David A. Shapiro   Dept. of Environmental Sciences, Virginia Institute of Marine Science, College of William and Mary, Gloucester Point, VA 23062, U.S.A.       The ability of a mammal to develop a highly specific antibody response to an offending pathogen occurs through the process of affinity maturation. However much of the literature dealing with teleostean antibody responses suggests that little, or no affinity maturation may occur within these taxa.  As rainbow trout (Oncorhynchus mykiss) antibodies are similar to multimeric mammalian IgM, we reasoned that affinity maturational shifts in intrinsic affinity may be similarly small.  Such small increases in affinity can, however, lead to potentially great avidity changes for multimeric antibodies.  We therefore employed a partition-based immunoassay which permits the dissection of a single antiserum into discrete, affinity-based antibody subpopulations. Such partitioning assays enhance the sensitivity and, particularly, the resolution of these antibodies over that which can be attained by fluorescence quenching or equilibrium dialysis.  Through the use of this technique, we were able to detect a consistent rise in affinity within trout anti-TNP antisera. However, analysis of affinity to a complex antigen such as a viral protein cannot be achieved via hapten inhibition techniques as described above.  To accomplish the latter, we utilized a denaturant-based affinity assay, recently employed in human clinical virology studies.  Through this technique we have acquired evidence that affinity maturation to a viral pathogen also occurs in trout.  The ability of this denaturant-based affinity technique to assess affinity was confirmed by simultaneous affinity assessment using anti-TNP in both the denaturant and quantitative partitioning assay. This work was supported by N.R.I. (U.S.D.A.) grants #97-03915 and 95-37024   Return to 25th Annual Eastern Fish Health Workshop Return to Leetown Science Center Home Page