Antibody affinity and clearance function studies in high and low antibody affinity mice. The effect of protein deficiency.

The effect of dietary manipulation on the relationship between macrophage clearance function and antibody affinity has been investigated in genetically selected high and low affinity mice. The results confirm that protein deprivation reduces the clearance rate of polyvinylpyrrolidone (Kpvp) and the relative affinity (Kr) of antibody to human serum albumin in mice normally producing high affinity antibody. Although protein deprivation of mice of the low affinity line reduced Kpvp, the mean Kr was not altered. Furthermore, although the two lines had significant differences in Kr values there were no demonstrable differences in macrophage clearance function as assessed by clearance of PVP, radiolabelled aggregated IgG and preformed antigen-antibody complexes. Analysis of values of Kr and Kpvp in individual animals indicated that these two parameters are not correlated. These experiments, provide further evidence for the profound effect of dietary manipulation on the immune response and suggest that in these genetically selected mice at least, the genetic control of antibody affinity is exerted at a level other than that measured by macrophage clearance function tests.