Cytokine levels of peripheral blood mononuclear cells in the clinical cases of Holstein calves infected with Mycoplasma bovis

Effect of supplementation with Saccharomyces boulardii CNCM I-1079 on vaccine response to an inactivated bacterial vaccine in young Japanese Black calves: A field trial

Saccharomyces boulardii group (SB group) calves were fed 2.0 × 1010 CFU/day of S. boulardii in milk replacer after 2 wk of age. All calves received inactivated vaccine for Histophilus somni, Pasteurella multocida, and Mannheimia haemolytica at 3 wk of age and 3 wk later. After vaccination, the SB group calves showed significantly higher (mean difference: 1.56-fold) antibody titer against H. somni than the control group. The number of calves with the antibody titer above the cut-off value for M. haemolytica of the SB group was significantly higher than that of the control, and the percentage was twice as high. In addition, the mRNA transcription of IL4 and IL10 in peripheral blood mononuclear cells at the booster of the SB group was significantly higher than those of the control. In conclusion, S. boulardii may have positively affected immune responses to the inactivated multi-bacterial vaccine in young calves in the field.

Effects of intra-articular inoculation with Mycoplasma bovis on immunological responses in calf joints

Mycoplasma arthritis that caused by Mycoplasma bovis exhibit severe lameness. This disease is difficult to cure with antibiotics, but the detailed pathological mechanisms have not been fully clarified. In this study, we examined the effects of intra-articular inoculation with M. bovis on immunological responses in calf joints. We inoculated three calves each with M. bovis or phosphate buffer saline (control) into the right stifle joint and dissected them at 15 days postinoculation. Mycoplasma bovis-inoculated calves exhibited swelling of the stifle joint, increases in synovial fluid, fibrin deposition, and cartilage thinning. Intracellular M. bovis was detected in synovial tissues analyzed by immunohistochemistry and transmission electron microscopy. Messenger RNA expressions of interleukin (IL)-1β, IL-6, IL-8, IL-12p40, and IL-17A in synovial fluid cells and synovial tissues from M. bovis-inoculated calves were significantly higher than those from control calves. Protein levels of these cytokines in synovial fluid from M. bovis-inoculated calves were markedly higher than those from control calves. Our study clarified that inoculation with M. bovis into the stifle joint induced the production of inflammatory cytokines by synovial fluid cells and synovial tissues, causing a severe inflammatory response in joints. Additionally, M. bovis could invade cells in synovial tissues, which may have aided it in evading antibiotics and host immune surveillance.