[Cross immunogenicity between Ia-associated invariant chains of chicken (Gallus domestiaus) and Muscovy duck (Cairina moschata)].

Objective: To explore the cross immunogenicity between Ia-associated invariant chain (Ii) of chicken (CIi) and Ii of Muscovy duck (MDIi).
Methods: The immunoreactivity between mouse anti-CIi serum and the MDIi expressed by prokaryotic cell, and the immunoreactivity between the mouse anti-MDIi serum and the CIi expressed by prokaryotic cell were detected through indirect ELISA. To detect the immunoreactivity between the mouse anti-CIi serum and the MDIi of the spleen tissues of Muscovy duck, and the immunoreactivity between the mouse anti-MDIi serum and the CIi of the liver tissues of chicken (tissular CIi), the fluorescence immunohistochemistry assay was performed using DyLight 488 affiniPure goat anti-mouse IgG as the second antibody. The fluorescence intensity was detected in each tissue by Leica fluorescence microscopic imaging system.
Results: The titer of ELISA reactivity between mouse anti-MDIi serum and the expressed CIi was 1:8000. The titer of ELISA reactivity between mouse anti-CIi serum and the expressed MDIi was 1:16 000. The mouse anti-CIi serum and anti-MDIi serum could respectively react with tissular MDIi and tissular CIi, showing visible green fluorescence in corresponding cells of each tissue. But the fluorescence intensities in the above tissues were weaker than those in positive control tissues in which the mouse anti-MDIi serum or anti-CIi serum reacted with tissular MDIi or tissular CIi respectively.
Conclusion: The cross immunogenicity between CIi and MDIi has been verified through the immunological experiments. The molecular basis of common antigen epitope formation between CIi and MDIi involves the conservation of the two Ii sequences, which reveals the high conservative property of Ii among variant birds from the perspective of immunology.