Changes Of Immunopathology In Peripheral Blood Of Chicks Infected With Avian Influenza Virus

In this study, staphytococcal protein A (SPA) rosette test, indirect enzymelinket immunosorbent assay (IELISA), cell culture technology and MTT assay were used to research the dynamic changes of the content of immunoglobulin (Ig)G, IgM, IgA , the number of T and B lymphocytes as well as the proliferative function of T and B lymphocytes to ConA or PMA in peripheral blood of 7-day-old and 21-day-old chicks infected with AIV. In order to reveal mechanism of immunity of different aged chicks infected with AIV and provide scientific referential basis for the production of vaccine of avian influenza.The results were as follows:The content of IgG, IgM, IgA , the number of T and B lymphocytes as well as the proliferative function of T and B lymphocytes to ConA or PMA in peripheral blood of 7-day-old and 21-day-old chicks infected with AIV were reduction on days 1~4 post infection (p.i.) in different degree(p<0.05 or p<0.01). Thereafter they begin to increase. The number increased significantly compared with control chicks on days 8~14 p.i(p<0.05 or p<0.01). The results indicated that humoral immune function in peripheral blood challenged with AIV was decreased transitory in acute illness during which cause secondary infection, but the increase data in later period also indicated that humoral immune of chicks play an important role in resisting AIV infection.The number of T lymphocytes and the proliferative function of T lymphocytes to ConA in peripheral blood of 7-day-old and 21-day-old chicks infected with AIV were decreased compared with control chicks and statistically significant on days 3 and 4 p.i.(p<0.01). The observations showed that cellular immune in chicks infected with AIV was critically inhibited, which is the primary element in immune subordinate chicks. Compared with infected 21-day-old chicks, 7-day-old infected chicks secrete lower antibody, remain inhibited T lymphocyte proliferitive function in longer period and recovery from illness more slowly. These indicated that 7-day-old chicks were more sensitive to AIV. The inhibited humoral and cellular immunity during acute illness was associated with high morbidity and mortality of chicks infected with AIV.