While most species of Hawaiian honeycreeper are highly susceptible to avian malaria, populations of the Hawaii amakihi (Hemignathus virens) are thriving at low elevations despite high infection rates of Plasmodium relictum. Due to their critical function in adaptive immunity, proteins encoded by Mhc genes may play a role in the recently evolved host defense mechanisms in these populations. A 454 Roche platform was used to generate 44,014 sequences representing 158 Mhc alleles from 46 captive amakihi involved in experimental challenges to avian malaria and 88 wild amakihi originating from Hawaii Island. Analysis of an NJ tree revealed 6 clusters of alleles occurring most often in surviving amakihi, and a significant association between survivorship and the presence of one or more alleles from these clusters was detected (p = 0.00006). Several of these alleles were also found in higher frequencies in low vs. high elevation populations. A similar analysis of 6,417 sequences representing 31 Mhc alleles from 19 experimentally infected i`iwi (Vestiaria coccinea) revealed a significant association between survivorship and the presence of one or more alleles from two clusters (p = 0.02). This is the first documentation of an Mhc association with survival to malaria in Hawaiian honeycreepers and is expected to enhance our understanding of host-parasite interactions in this natural disease system while also providing a predictive tool for conservation and management.
- Copyright © 2013 by The American Association of Immunologists, Inc.