An experimental vaccine composed of two adjuvants gives protection against Mycoplasma bovis in calves

Mycoplasma bovis antibody dynamics in naturally exposed dairy calves according to two diagnostic tests

“…A similar phenomenon has been seen with Salmonella Dublin [4] and Virtala et al [5] also found that young calves often fail to seroconvert to common respiratory pathogens including M. bovis , although this was assessed using a different assay. The BioX ELISA was also used in a vaccine challenge study by Dudek et al [15]. In the positive control group, which consisted of five- to six-week-old heifers intratracheally challenged with M. bovis , the antibody response increased only slightly to a maximum of approximately 50 ODC% at 4 weeks after challenge, and thereafter declined slightly.…”

Status of the development of a vaccine against Mycoplasma bovis

“…Saponin was used as an adjuvant in the first experimental M. bovis vaccine that showed promising results [37] and a combination of saponin and Emulsigen Ò was used in later trials [36], also with encouraging results. The ability of M. bovis to invade and persist intracellularly, suggests that balanced Th-1/Th-2 response may be a better choice [70,71].…”

“…Factors such as the age of the animals, the challenge dose, the challenge protocol and the role of other respiratory pathogens must be taken into account. A number of laboratories have reported success of their experimental vaccines after multiple challenges (up to three times) of young animals (ranging from 3 weeks to 5 months-old) with large doses of M. bovis (in the range of 10 9 to 10 10 colonyforming units [cfu]) [36][37][38]. In these reports, the success of the challenges is associated with the onset of clinical signs such as dyspnea, nasal discharge, moderate fever, weight loss, the presence of characteristic macroscopic lesions, such as lung consolidation, adhesions, and caseonecrotic pneumonic lesions; microscopic lung lesions, such as suppurative bronchiolitis, lymphoid hyperplasia, intra-alveolar and intrabronchial exudates, and coagulative necrosis, and isolation of M. bovis from challenged animals.…”

“…A Polish strain of M. bovis (KP795974) was used as a basis of the vaccine, which was administered to three to four-week-old cattle. M. bovis-specific antibodies were reported to increase up to 200% of a positive control and after vaccination, the animals were challenged with the same strain [36]. The vaccine was deemed to be protective after comparing clinical signs between the groups, but the pre-challenge clinical findings in the positive control group were not described.…”

“…In addition, the authors do not explain the reason for increases in the respiratory rate and nasal discharge in the vaccinated group before challenge. Finally, differences in the lung lesions scores were reported for only two animals from each group [36].…”