The Effects Of Recombinant Chicken Interferon-γ On Immune Functions In Chickens

Interferon (IFN), induced by special inducers, is a kind of glycoprotein characterized by high bioactivity and broad-spectrum antiviral activity in the homogeneity animal cells. It has been utilized for a variable of diseases caused by virus in human being. Although it plays important roles on antiviral effects such as New Castle disease, infectious bursa disease, infectious bronchitis, avain fluenza and also plays important roles on immunomodulatory effects as a immunologic adjuvant in the field of livestock, restructuring chicken gamma interferon (rChIFN-γ) is a kind of nonspecific broad-spectrum antiviral biological agents. However, there are still broad researching work of rChIFN-γ in the lab and veterinary clinic to be done. The aim of this study is to evaluate the synergistic reaction, the specific and unspecific immune functions in chickens after IBDV vaccine combined with rChIFN-γ administration by different dosage and administration route.1,80 28-days-old chickens were randomly divided into eight groups such as high dosage of rChIFN-γ (5×103 U/each) oral administration group, middle dosage of rChIFN-γ (103 U/each) oral administration group, low dosage of rChIFN-γ (500 U/each) oral administration group, high dosage of rChIFN-γ (5×103 U/each) injection group, middle dosage of rChIFN-γ (103 U/each) injection group, low dosage of rChIFN-γ (500 U/each) injection group, unactivitied IBDV vaccinated group (positive control group) and negative control group, respectively. The blood samples of all experimental chickens were collected before and at 0 d,7 d,14 d,21 d after rChIFN-γ administration. The results showed that IBD antibody titers increased rapidly and keeped higher level for a long time after IBDV vaccine administration combined rChIFN-γ. IBD antibody levels in IBDV vaccine combined rChIFN-γ chickens are significantly higher than those of normal control chickens, especially in the middle dosage injection group. The tendency of IBD antibody titer inductions in rChIFN-γ oral administration groups increased slowly than that in rChIFN-γ injection groups, and the IBD antibody titer levels in rChIFN-γ oral administration groups were lower than that in rChIFN-γ injection groups compare to the same dosage and the same administration time.2,150 28-days-old chickens were randomly divided into six groups such as high dosage of rChIFN-γ (5×103 U/each) injection group, middle dosage of rChIFN-γ (103 U/each) injection group, high dosage of rChIFN-γ (5×103 U/each) oral administration group, middle dosage of rChIFN-γ (10 U/each) oral administration group, thymopeptides administration group (positive control group) and negative control group, respectively. The blood samples of all experimental chickens were collected at 0 d,7 d,14 d,21 d after rChIFN-γ administration for the detection of lymphocyte transformation rate (LBT), IL-2, IL-4, IgA, IgG and IgM in peripheral blood, and tissue samples were taken for immune organ index and histopathological changes. The results reveal that LBT in peripheral blood and the Thymus index can be significantly increased after rChIFN-γ administration. rChIFN-γ can increase T lymphocyte proliferation and mature, and promote the cellular immune response; After rChIFN-γ administration, the humoral immune response of experimental chickens can be obviously increased with IgG and IgM induction; There are no obvious influence on IL-2 and IL-4 in peripheral blood and growth induction after rChIFN-γ administration. The results also showed that it is different for promoting the abilities of immune functions with different rChIFN-γ administration routes and different rChIFN-γ dosages.