Figure 4.1. Affinity versus specificity of host immunity.

Figure 4.1

Affinity versus specificity of host immunity. The two triangles show the range of antigens bound by a particular antibody or T cell. A narrow range implies high discrimination between parasite antigens and high specificity. Detection of binding depends on the stringency of conditions used in the assay. For example, if only very strong binding can be detected in the assay (high stringency), then typically the antibody or T cell will appear to bind a narrower range of antigens and will therefore have higher specificity. Reducing the concentration of antibodies or T cells also increases the stringency because fewer host-parasite complexes form. In the example shown, the relation between affinity and specificity changes with stringency. Low stringency raises the relative specificity of the high-affinity antibody or T cell, medium stringency causes higher relative specificity for the low-affinity antibody or T cell, and high stringency drops the low-affinity reaction below the detection threshold.

From: Chapter 4, Specificity and Cross-Reactivity

Cover of Immunology and Evolution of Infectious Disease
Immunology and Evolution of Infectious Disease.
Frank SA.
Princeton (NJ): Princeton University Press; 2002.
Copyright © 2002, Steven A Frank.

NCBI Bookshelf. A service of the National Library of Medicine, National Institutes of Health.