Differentially expressed transcripts in cattle protected against Mycoplasma bovis with modified-live Mannheimia haemolytica expressing Mycoplasma antigens
Mannheimia haemolytica strains expressing an inactive, yet immunogenic leukotoxoid, fused with or without antigenic domains of Mycoplasma bovis Elongation Factor Tu (EFTu) and Heat Shock protein 70 (HSP70) were used to challenge calves. At day 0, control calves (n= 6) intranasally received the M. haemolytica strains expressing the inactive leukotoxoid (MH), while the treated group (n= 6) received M. haemolytica expressing the inactive leukotoxoid with the EFTu and HSP70 antigens. On day 34, all animals were pre-challenged with bovine herpesvirus 1 to predispose to virulent Mycoplasma bovis. Four days later all the animals were challenged with M. bovis isolate KRB5. Animals were euthanized 18-20 days post-challenge. RNA was extracted and sequenced from liver, palatine tonsil, spleen, retropharyngeal and tracheal-bronchial lymph nodes to identify differentially expressed transcripts associated with a Mycoplasma bovis challenge in cattle.