Does peptidome mimicry shape host-parasite coevolution?

Area of Science:

• Immunology
• Evolutionary Biology
• Parasitology

Background:

• Vertebrate immunity recognizes peptides absent from the host proteome.
• The peptidome mimicry hypothesis (PMH) extends this principle to host-parasite interactions.
• Coevolutionary dynamics can lead to reduced parasite peptide repertoires and convergence toward host peptide sequences.

Purpose of the Study:

• To explore the implications of the peptidome mimicry hypothesis (PMH) in understanding host-parasite coevolution.
• To investigate how PMH explains parasite host specificity and hybrid susceptibility.
• To demonstrate the utility of PMH in inferring parasite origins and in vaccine target nomination.

Main Methods:

• Theoretical framework development based on immune recognition principles.
• Analysis of parasite peptide vocabularies, including examples like SARS-CoV-2.
• Comparative analysis of host and parasite peptide repertoires.

Main Results:

• PMH predicts systematic 'missing peptides' in parasites due to coevolution.
• The hypothesis explains narrow host specificity and increased susceptibility in interspecies hybrids.
• Analysis of SARS-CoV-2 peptide data supported its host-switching history reconstruction.
• PMH offers a method for nominating immunogenic peptide targets for vaccine development.

Conclusions:

• The peptidome mimicry hypothesis provides a framework for understanding host-parasite coevolutionary patterns.
• PMH aids in reconstructing parasite evolutionary histories and identifying potential original hosts.
• This hypothesis offers a complementary approach to existing methods for selecting vaccine targets.