Modulation of Marek's Disease by PBMCs

One hundred and twenty chickens were randomly divided into 6 groups: PBMCs-uninfused and MDV-unchallenged (control), TCRγδ-unactivated PBMCs-infused and MDV-unchallenged (TCRγδ-/MDV-), TCRγδ-activated PBMCs-infused and MDV-unchallenged (TCRγδ+/MDV-), cell-uninfused and MDV-challenged (MDV+), TCRγδ-unactivated PBMCs-infused and MDV-challenged (TCRγδ-/MDV+), and TCRγδ-activated PBMCs-infused and MDV-challenged groups (TCRγδ+/MDV+). At 21 days of age, 3 × 10⁷ cultured PBMCs in 500 μL of PBS were injected intraabdominally to the original chicken (autologous cell infusion). On the same day of infusion, chickens in the MDV+, the TCRγδ-/MDV+, and the TCRγδ+/MDV+ groups were challenged with 500 plaque-forming units of RB1B intraabdominally. The same volume of PBS was injected as a control for cell infusion and virus challenge to each control group. Five chickens in each group were euthanized by CO₂ inhalation at 4, 10, and 21 dpi. The spleen and lungs were collected aseptically in 1 × Hank’s balanced salt solution (HBSS) (Gibco) supplemented with 100 U/mL of penicillin and 100 μg/mL of streptomycin and stored on ice until further use. Blood samples were collected using heparinized syringes. Feather tips, spleen, lungs, and PBMCs were collected in RNAlater (Qiagen Inc., Mississauga, ON, Canada) and stored at −20 °C. Tumor incidence and scoring of MDV-challenged chickens were determined at 21 dpi (n = 10) [21 (link)]. The spleen, lungs, liver, kidneys, heart, genitalia, proventriculus, gizzard, pancreas, intestine, and skin were assessed for gross tumor lesions. Tumor scoring was calculated by the number of tumor-bearing organs. The neoplastic lesion score of chickens which did not have any gross tumor lesions in any organs described above was evaluated as 0.