Assessment of the cell-mediated immune response in chickens by detection of chicken interferon-γ in response to mitogen and recall Newcastle disease viral antigen stimulation

Abstract

The potential of a capture enzyme-linked immunosorbent assay (ELISA) specific for chicken interferon-g (ChIFN-g) has been evaluated as a tool to assess cell-mediated immunity (CMI) in the chicken. In a first step, ChIFN-g production and cell proliferation of mitogen-activated chicken splenocytes have been compared. In general, for each of the stimulation conditions where significant proliferation was observed, production of ChIFN-g could be measured by ELISA. In our hands, the combination of ionomycin and phorbol-12-myristate 13-acetate or the use of recombinant chicken interleukin-2 gave the most satisfactory results. Then, the CMI response induced by live or killed Newcastle disease virus (NDV) vaccines has been evaluated sequentially by ex vivo antigen-specific ChIFN-g production and cell proliferation of splenocytes from immune chickens. The ex vivo data showed that both types of NDV vaccines are capable of stimulating CMI responses to NDV in chickens as measured by the ChIFN-g ELISA. However, most of the chickens vaccinated with the live vaccine produced ChIFN-g after antigen recall stimulation, from 2 to 4 weeks after vaccination, when only some chickens vaccinated with the inactivated vaccine showed a specific response 4 weeks after vaccination. No significant proliferative responses to either NDV vaccine were detectable during the 4 weeks of the study. From our results, it appears that antigen-specific ChIFN-g production can be used as a good indicator of actively acquired immunity to NDV and that the sensitivity range of the capture ELISA test is well adequate to measure ex vivo release of ChIFN-g.

Comparison of the effectiveness of rHVT-H5, inactivated H5 and rHVT-H5 with inactivated H5 prime/boost vaccination regimes in commercial broiler chickens carrying MDAs against HPAI H5N1 clade 2.2.1 virus

“…Hatchery vaccination administered at day old, if effective, would optimize vaccine coverage and flock protection levels with the use of limited resources (Peyre, 2014). One of the main limitations of inactivated vaccines is that they mainly induce humoral immune response (Bermudez & Stewart-Brown, 2003;Lambrecht et al, 2004;Marangon & Busani, 2006;Rauw, et al, 2012), and face high levels of interference with MDAs when administered within the first 10 days of age (De Vriese et al, 2010;Maas et al, 2011;Abdelwhab, et al, 2012b), as per current practice in Egypt. The rHVT-H5 vaccine, expressing the HA gene of a HPAI H5N1 clade 2.2 A/Swan/Hungary/499/2006 strain inserted into the FC-126 strain of the HVT vector, has been developed to fight current AI threats to the poultry industry (Rauw, et al 2011).…”

Comparison of single 1-day-old chick vaccination using a Newcastle disease virus vector with a prime/boost vaccination scheme against a highly pathogenic avian influenza H5N1 challenge

“…The mitogens phorbol 12-myristate 13-acetate (PMA) and ionomycin (Iono) were purchased from Sigma (Diegem, Belgium). NDV and H5N2 recall antigens were prepared from NDV La Sota and H5N2 LPAI (A/Chicken/Belgium/150VB/99) strains, respectively, as described previously (Lambrecht et al, 2004; and were named NDV and H5N2 all proteins (prot-NDV and prot-H5N2 It is important to note that only a small amount of HPAIV antigen (H5N1) was detected after inactivation and purification, which was not enough to be used in ELISA tests, whereas a large quantity of purified LPAI virus (H5N2) without inactivation was obtained using the same protocol . In order to complete the characterization of H5 humoral response, the challenge strain (H5N1) and a reference strain (H5N3; Laboratory of European Union, VLA, Weybridge, UK) were used to perform the HI tests because of their high antigenic similarity.…”

“…Briefly, splenic lymphocytes were activated by mitogens (PMA/Iono, 0.1 µg/ml), as positive control of ex vivo activability of lymphocytes, and by NDV and AIV recall antigens (prot-NDV and prot-H5N2, 1 µg/ml). ChIFNγ production was measured by capture ELISA as described previously (Lambrecht et al, 2004) and using a commercially available assay (catalogue number #CAC1233; Biosource Europe, Nivelles, Belgium). Cellular immune responses were expressed as stimulation indices (SIs) that were calculated for each bird by dividing the optical density (OD) values of mitogen-activated and antigen-activated lymphocytes by the OD of non-activated lymphocytes (Rauw et al, 2009), and the SIs per group were calculated.…”

Opinion of the Scientific Panel on Animal Health and Welfare (AHAW) to review Newcastle disease focussing on vaccination worldwide in order to determine its optimal use for disease control purposes

“…Cell-mediated immune response (CMI) may be detected as early as 2-3 days after infection with live vaccine strains but by itself is not sufficient to protect against virulent APMV-1 challenge (Reynolds and Maraqa, 2000b). Studies on groups of chicken vaccinated with either live or killed vaccines demonstrated cell mediated immunity in both goups, but detected earlier and stronger primary CMI responses after live vaccination (Lambrecht et al, 2004). However, T cells but not B cells may be essential for virus clearance (Russel et al, 1997).…”