Fig. 3.

Effect of serum IgG concentration on antibody function. a Schematic representation of data from Kelton et al. (1985) [3], showing effect of serum IgG concentration on clearance rate of IgG-sensitised red blood cells (RBCs). Unusually fast clearance rate in a patient with hypogammaglobulaemia was reduced to a normal level following gamma globulin treatment. b Schematic representation of data from Preithner et al. (2006) [1], showing how the inhibitory effect of serum IgG depends on target antigen density. The inhibitory effect of competing serum IgG can be overcome using higher concentrations of therapeutic antibody when target density is high; however, the maximum antibody response is limited where target density is low, and cannot be overcome with increasing therapeutic antibody concentration. (For interpretation of the references to colour in this figure legend, the reader is referred to the web version of this article.)