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Published on: February 28, 2019
Major histocompatibility complex heterozygote superiority during coinfection
Erin E McClelland1, Dustin J Penn, Wayne K Potts
1Biology Department, University of Utah, Salt Lake City, UT 84112, USA.
Infection and Immunity
|March 26, 2003
Summary
Major histocompatibility complex (MHC) heterozygote superiority was observed in mice with multiple infections. This finding explains how disease-susceptibility alleles persist in populations, contributing to MHC diversity.
Area of Science:
- Immunogenetics
- Evolutionary biology
- Population genetics
Background:
- Major histocompatibility complex (MHC) genes are crucial for immune recognition.
- Many MHC alleles increase susceptibility to infectious and autoimmune diseases.
- The persistence of deleterious MHC alleles in populations remains a subject of debate.
Purpose of the Study:
- To test the hypothesis that MHC heterozygote superiority arises from masking allele-specific pathogen susceptibilities during coinfections.
- To provide experimental evidence for MHC heterozygote advantage in the context of multiple pathogen exposures.
Main Methods:
- Experimental coinfections using Salmonella enterica and Theiler's murine encephalomyelitis virus (TMEV) in MHC-congenic mice.
- Mice possessed MHC haplotypes with differential resistance to each pathogen.
- Comparison of pathogen loads in MHC heterozygotes versus homozygotes.
Main Results:
- MHC heterozygotes demonstrated significant superiority over homozygotes in 7 out of 8 comparisons (P = 0.0024).
- Heterozygotes exhibited a 41% reduction in mean standardized pathogen load compared to homozygotes (P = 0.01).
- No heterozygote superiority was found when MHC haplotypes had similar pathogen susceptibility profiles.
Conclusions:
- This study provides the first experimental evidence for MHC heterozygote superiority against multiple pathogens.
- This mechanism contributes to the evolution and maintenance of MHC genetic diversity.
- It offers an explanation for the persistence of MHC alleles associated with disease susceptibility.
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