Evaluation Of Immunogenicity and Protective Potential of Recombinant Mmm Proteins Against Contagious Bovine Pleura-Pneumonia

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kenya Agriculture Research Institute
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kenya Agriculture Research Institute
Contagious bovine pleura-pneumonia (CBPP) is a fatal lung disease caused by Mycoplasma mycoides subsp. mycoides (Mmm). The aim of this study was to identify proteins that protect against the disease and could be included in a subunit vaccine against CBPP. Sixty six recombinant proteins from Mmm had been selected for their expression on the cell surface and their reactivity with sera from cattle immunized with the current live vaccine. Groups of cattle were immunized with pools of five antigens and challenged with CBPP. Three trials using a total of 170 heads of boran cattle were conducted. Each trial comprised 60 cattle (50 for third trial) which were grouped into randomized cohorts of 10 animals. Each animal in treatment group was injected subcutaneously with pools of five different proteins co-formulated with an adjuvant. Two weeks after a booster inoculation, cattle were endo-bronchially challenged with the Afade strain of Mmm and were clinically, serologically, pathologically and bacteriologically monitored. Humoral and cellular immune responses were monitored by ELISA and lympho-proliferation assays, respectively. Protection levels were measured using the pathology index, calculated from pathology scores in the vaccinated and in the control groups. Analysis of antibody and cellular immune responses revealed that the proteins triggered specific responses, albeit to varying magnitude. Judging from the pathology data, there was evidence of protection conferred by some proteins, while others appeared to exacerbate the pathological lesions in the vaccinated cattle. The results indicate that four groups showed some level of protection against experimental challenge. The proteins used to immunize these groups contain important candidates in the development of a novel subunit vaccine against CBPP and further experiments are needed to identify the most effective antigens.