Send to

Choose Destination
Evol Appl. 2009 Feb;2(1):122-31. doi: 10.1111/j.1752-4571.2008.00052.x. Epub 2008 Dec 8.

Why do adaptive immune responses cross-react?

Author information

Institutes of Evolution, Immunology & Infection Research, School of Biological Sciences, University of Edinburgh, Ashworth Laboratories King's Buildings, Edinburgh, UK.


Antigen specificity of adaptive immune responses is often in the host's best interests, but with important and as yet unpredictable exceptions. For example, antibodies that bind to multiple flaviviral or malarial species can provide hosts with simultaneous protection against many parasite genotypes. Vaccinology often aims to harness such imprecision, because cross-reactive antibodies might provide broad-spectrum protection in the face of antigenic variation by parasites. However, the causes of cross-reactivity among immune responses are not always known, and here, we explore potential proximate and evolutionary explanations for cross-reactivity. We particularly consider whether cross-reactivity is the result of constraints on the ability of the immune system to process information about the world of antigens, or whether an intermediate level of cross-reactivity may instead represent an evolutionary optimum. We conclude with a series of open questions for future interdisciplinary research, including the suggestion that the evolutionary ecology of information processing might benefit from close examination of immunological data.


heterologous immunity; information processing; optimal discrimination; optimal immunology

Supplemental Content

Full text links

Icon for Wiley Icon for PubMed Central
Loading ...
Support Center