Use of recombinant protein fragments from Mycoplasma mycoides subsp. Mycoides sc to jmprove Contagious bovine pleuropneumonia (CBPP) t cell And antibody based assays

Abstract

Contagious bovine pleuropneumonia (CBPP), caused by the bacterium Mycoplasma mycoides subsp. mycoides biotype Small Colony type (MmmSC), is a highly contagious respiratory disease that causes significant losses of cattle in more than 26 countries of sub-Saharan Africa. Development of reliable diagnostic tools is key to helping monitor disease 'prevalence and incidence. This study screened selected recombinant MmmSC antigens for their potential in antibody based diagnostics and their ability to activate memory T cells. Gene fragments from the surface located MmmSC molecules were expressed in Escherichia coli expression systems and the recombinant protein fragments purified for further usage: They were tested against ten sera from. infected and uninfected cattle to evaluate their potential for improved CBPP diagnostic. They were also tested for their ability to stimulate memory T lymphocytes from experimentally MmmSC infected cattle. Peripheral blood mononuclear cells (PBMCs) from ten. cattle were. stimulated with recombinant MmmSC antigens for 72 hours and Il-Ny secreticn was measured using Bovigam kit {AgriQuality, Australia). The different responses elicited by the antigens were compared using student t-test. The results showed that none of the recombinant fragments induced IFNy higher than the cut- off value of (2:0.7). However, heat inactivated MmmSC lysate induced IFNy secretion (P <0.05) but the recombinant fragments did not induce significant. amounts of IFNy secretion (P > 0.05) when preinfection and post infection time points were . compared. Also, none of the recombinant protein fragments was recognized by post infection. sera. The results showed that antibody based diagnostics based on these particular recombinant protein fragments is not feasible. The study concluded that the recombinant protein fragments tested did not have strong T cell epitopes or T cells failed to migrate to circulation. Absence of antibodies suggested lack of B cell epitopes in the structure of these recombinant fragments.