Fetal bovine serum (fbs)

HD11 cells were obtained from the laboratory of Dr. Mark Parcells (University of Delaware). The cells were maintained at 37 °C, 5% CO₂, and 95% humidity in Iscove’s Modified Dulbecco’s Media (IMDM; GE Life Sciences, Logan, UT, USA) with 10% fetal bovine serum (Midsci, Valley Park, MO, USA) and 1% 1.5 mM L-glutamine containing penicillin and streptomycin (Gibco, Grand Island, NY, USA).
Salmonella Enteritidis, resistant to nalidixic acid and novobiocin, was donated by Dr. Haiqi He, US Department of Agriculture Research Service. The strain was conserved at −80 °C in tryptic soy broth (TSB; Becton, Dickinson and Company, Sparks, MD, USA) and supplemented with 20% (v/v) glycerol. The day prior to the experiments, it was thawed and cultured overnight in TSB supplemented with 25 μg/mL novobiocin and 20 μg/mL nalidixic acid (Sigma-Aldrich, St. Louis, MO, USA) at 37 °C.

HD11 cells are referred to as chicken macrophage-like cells because they represent an immortalized bone marrow derived cell line that is transformed with the avian myelocytomatosis type MC29 virus [18 (link)]. The cells were maintained in cell culture media containing Iscove’s Modified Dulbecco’s Media (IMDM) (GE Life Sciences, Logan, UT, USA) with 10% fetal bovine serum (Midsci, Valley Park, MO, USA) and 1% 1.5 mM L-glutamine (containing penicillin and streptomycin) (Gibco, Grand Island, NY, USA) at 37 °C, 5% CO₂, and 95% humidity. When required, cells were counted using a hemocytometer and a dilution factor of 10 in trypan blue (Sigma-Aldrich, St. Louis, MO, USA). HD11 cells were obtained from the laboratory of Dr. Mark Parcells, University of Delaware.

MAC-T [7 (link)] (gift from Dr. Juan Loor from University of Illinois) and MAC-T stably infected with BLV (MAC-T BLV) cells were cultured in Modified Eagle's medium (MEM) supplemented with 10% fetal bovine serum (MIDSCI, Valley Park, MO, USA) and 1 μg/ml hydrocortisone (Sigma-Aldrich, Saint Louis, MO, USA) at 37°C with 5% CO₂. MAC-T BLV cells were infected with PBMCs from BLV positive animals from Kansas, United States, as previously described [5 (link)]. Cultures were passaged upon approaching confluence using standard techniques, and MAC-T cells were always passed in the first place. MAC-T BLV cells were subcultured after MAC-T to avoid cross-contamination. For RNA seq analysis, MAC-T samples were obtained in passages 8, 30, and 36, while the three samples from MAC-T BLV were obtained in passage 35 post-infection (from 3 different infections with BLV). Each biological replicate consisted of MAC-T cells infected with the same batch of PBMCs obtained from a cow infected with BLV. All the cell lines were harvested for RNA extraction when they reached confluency.