Transfer factor from REV-challenged chicken spleens enhances protection against reticuloendotheliosis virus infection in chicks.

Reticuloendotheliosis virus (REV) is an immunosuppressive avian pathogen known to compromise growth performance and immune function in young chickens, with effective prophylactic or therapeutic interventions still lacking. To investigate the inhibitory effects of transfer factors (TF) extracted from spleens of different sources on REV infection, this study used TF isolated from spleens of REV-challenged chickens and non-challenged control chickens. Chicks received TF pretreatment before being infected with REV, and the utility of TF for REV management was assessed using multiple metrics: body weight gain, immune organ development index, and viral load quantification.The results showed that both sources of TF alleviated REV-induced growth retardation, hepatosplenomegaly, and atrophy of the thymus and bursa of Fabricius in chicks, with TF from REV-challenged chicken spleens exhibiting significantly better efficacy (P < 0.01). TF from REV-challenged spleens was more effective in reducing REV excretion through the cloaca and showed greater advantages in inhibiting REV replication in organs such as the spleen and thymus. This study provides a novel source-based strategy for the clinical prevention and control of REV infection.