Co-infection of reticuloendotheliosis virus (REV) and avian leukosis virus subgroup J (ALV-J), which can cause suppressed immunity and vaccination failure, frequently occurs in chicken flocks in China. Taishan Pinus massoniana pollen polysaccharide (TPPPS) and propolis (PP) have been proven to possess immune modulatory effects and improve the immune effects of vaccines. This study aimed to investigate the immune modulatory ability of TPPPS and PP on chickens co-infected with immunosuppressive viruses. Prior to the study, chickens were artificially established as REV and ALV-J co-infection models. Four randomly assigned groups of these immunosuppressed chickens were successively administered with TPPPS, PP, mixture of TPPPS and PP (TPPPS-PP), or phosphate-buffered saline (PBS) for three days. At nine days old, the four immunosuppressed groups, as well as one normal group, were inoculated with the attenuated Newcastle disease (ND) vaccine. During the monitoring period, the indices of immune organ weight, lymphocyte transformation rates, CD4(+) and CD8(+) T-lymphocyte counts in peripheral blood, IL-2 and IFN-γ secretions, serum antibody titers of ND vaccine, and viral loads in spleens were determined. The results showed that chickens administered with TPPPS, PP, or TPPPS-PP could significantly enhance the levels of the above immune parameters compared to chickens in the PBS group. We observed the strongest immunity in the TPPPS-PP group, which indicates that the combination of TPPPS and PP versus TPPPS or PP alone, could generate better effects on improving the immune system effectiveness of immunosuppressed chickens.
Keywords: Co-infection; Immunomodulator; Immunosuppression; Polysaccharide; Propolis.
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