Distribution patterns of influenza virus receptors and viral attachment patterns in the respiratory and intestinal tracts of seven avian species

Taiana Costa,Rosa Valle,Antonio Ramis,Debby Van Riel,Ayub Darji,Aida J Chaves,Thijs Kuiken,Natàlia Majó

doi:10.1186/1297-9716-43-28

Abstract

This study assessed the presence of sialic acid α-2,3 and α-2,6 linked glycan receptors in seven avian species. The respiratory and intestinal tracts of the chicken, common quail, red-legged partridge, turkey, golden pheasant, ostrich, and mallard were tested by means of lectin histochemistry, using the lectins Maackia amurensis agglutinin II and Sambucus nigra agglutinin, which show affinity for α-2,3 and α-2,6 receptors, respectively. Additionally, the pattern of virus attachment (PVA) was evaluated with virus histochemistry, using an avian-origin H4N5 virus and a human-origin seasonal H1N1 virus. There was a great variation of receptor distribution among the tissues and avian species studied. Both α-2,3 and α-2,6 receptors were present in the respiratory and intestinal tracts of the chicken, common quail, red-legged partridge, turkey, and golden pheasant. In ostriches, the expression of the receptor was basically restricted to α-2,3 in both the respiratory and intestinal tracts and in mallards the α-2,6 receptors were absent from the intestinal tract. The results obtained with the lectin histochemistry were, in general, in agreement with the PVA. The differential expression and distribution of α-2,3 and α-2,6 receptors among various avian species might reflect a potentially decisive factor in the emergence of new viral strains.

Highlights

Wild aquatic birds are generally considered to be the source of all influenza viruses found in mammal and avian species, including humans, pigs, horses, minks, marine mammals, cats, and a great number of domestic avian species [1]
The NA pretreatment, used as a control, removed all the binding sites for the Sambucus nigra agglutinin (SNA); very low levels of staining for Maackia amurensis agglutinin II (MAAII) remained after the NA treatment in connective tissue of the lamina propria in the respiratory and intestinal tracts of all the species studied, and was considered as non-specific staining
The distribution of influenza receptors in the respiratory tract is given in Table 1 and the results from nasal cavity and trachea are illustrated in Figures 1 and 2, respectively

Summary

Introduction

Wild aquatic birds are generally considered to be the source of all influenza viruses found in mammal and avian species, including humans, pigs, horses, minks, marine mammals, cats, and a great number of domestic avian species [1]. It was observed that the H5 and H7 avian influenza virus subtypes could be directly transmitted from poultry to humans, in spite of having a-2,3 receptor specificity [11,12,13]. This observation encouraged investigators to study the role of a-2,3 and a-2,6 receptors in the species barrier, and led to the description of a-2,3 receptors in the human lower respiratory tract, which may partially explain the localization and severity of H5N1-associated pneumonia in humans [14,15]

Methods

Results

Conclusion