concanavalin-a and Influenza-in-Birds

In humans and other mammals, the α-chain of interleukin-2 (IL-2) receptor (CD25) is induced and expressed on the cell surface after lymphocyte activation and is released from the membrane of activated cells as a smaller soluble form (sCD25). However, little is known about avian sCD25. In the present study, we developed an antigen capture enzyme-linked immunosorbent assay (AC-ELISA) to detect serum sCD25 in ducks, and we used flow cytometry (FCM) to analyze the frequency of CD25(+) cells in the peripheral blood of ducks infected with H9N2 or H5N1 avian influenza virus (AIV) or serotype II Riemerella anatipestifer (RA). Using the AC-ELISA, duck sCD25 molecules were detected in the supernatant and lysates of concanavalin A (Con A)-stimulated peripheral blood mononuclear cells (PBMC), and in the serum of ducks infected with H5N1 virus and RA. However, no sCD25 was detected in the serum of H9N2 AIV-infected ducks. FCM analysis revealed that CD25(+) cells were upregulated within the PBMC of RA-infected ducks throughout the experiment until death, while in the PBMC of H9N2- and H5N1 AIV-infected ducks, the frequency of CD25(+) cells increased in the early stage of infection and then returned to a lower level. Our findings confirm that the dynamics of sCD25 and CD25(+) cells are different in the peripheral blood of ducks infected with H9N2 virus, H5N1 virus, and RA.

Topics: Animals; Concanavalin A; Ducks; Enzyme-Linked Immunosorbent Assay; Flavobacteriaceae; Flavobacteriaceae Infections; Flow Cytometry; Influenza A Virus, H5N1 Subtype; Influenza A Virus, H9N2 Subtype; Influenza in Birds; Interleukin-2 Receptor alpha Subunit; Kinetics; Leukocytes, Mononuclear; Lymphocyte Count; T-Lymphocytes