Antigenicity and Potential Use of A Novel Brucella Multiepitope Recombinant Protein in the Diagnosis of Brucellosis

Abstract

16Currently, brucellosis is a reemerged zoonotic infectious disease with an 17 increased incidence in recent years. A simple, rapid and sensitive method for 18 diagnosing brucellosis has important significance for early diagnosis and early 19 treatment, which can help to reduce medical burden and economic loss. Previously, a 20 multiple epitope recombinant protein was constructed based on linear B-cell epitope 21 prediction tools. In this study, the recombinant protein was used as an antigen to study 22 the immune response produced by immunized mice, and goat serum was used to 23 verify its diagnostic accuracy.The production of antibodies was successfully induced 24 in the vaccinated mice. Through analyzing the serum antibody subtypes, the primary 25 antibody was identified as IgG. Flow cytometric analysis revealed that the percentage 26 of CD4+, CD8+ and the CD4+/CD8+ ratios were increased by T cell subsets in mouse 27 splenocytes, indicating that the recombinant protein induced a strong immune 28 response in mice and that it had strong immunoreactivity. Using indirect ELISA, the 29 recombinant protein correctly diagnosed positive and negative brucellosis samples. 30Compared with the whole bacterial antigen, the recombinant protein had a weaker 31 sensitivity but a stronger specificity.In this study, animal experiments showed that the 32 recombinant protein had good antigenicity, and indirect ELISA indicates that it can be 33 used as an antigen to diagnose brucellosis. Therefore, the recombinant protein is a 34 3 potential candidate antigen for brucellosis vaccine development and serological 35 diagnosis. 36 37 38 4 235 can infect humans and domestic animals[16], and human B. melitensis is the main 236 13 Brucella species worldwide, which accounts for 80 % to 90 % of the total number of 237 brucellosis cases in China[17,18]. Therefore, brucellosis sera infected by B. melitensis 238 were used in this study to further verify the diagnostic accuracy of the recombinant 239 protein. The results of indirect ELISA showed that the recombinant protein had good 240 ability to recognize the positive-and negative-brucellosis sera. To investigate the 241 sensitivity and specificity of the rMEP, ROC curve analysis was performed, and the 242 results indicated that the rMEP had better specificity than the whole bacterial antigen. 243 The AUC indicated that both the recombinant protein and the whole bacterial antigen 244 could distinguish positive samples from negative samples with a high level of 245 accuracy (0.9 < AUC < 1)[19]. The following work should be to expand the range of 246 strains to further verify their specificity. 247 Conclusion 248 The recombinant protein was used to immunize mice and successfully induced 249 the production of antibodies in mice, resulting in a strong immune response, 250 demonstrating that the recombinant protein had good immunogenicity. The indirect 251 ELISA results proved that the recombinant protein had good sensitivity and 252 specificity for diagnosing brucellosis in goat serum. It is a p...

Importance of brucellosis control programs of livestock on the improvement of one health

“… 1989 ; Barrionuevo and Giambartolomei 2019 ; Yin et al. 2019 ). Efforts were instead concentrated on surface antigens (described as R in rough strain and A, M in smooth strains) and lipopolysaccharide (LPS) expected to trigger specific antibody response (Mancilla 2016 ; Głowacka et al.…”

“…Moreover, the genome also lacks the numerous other common virulence genes such as fimbriae, antigenic variation, capsules, cytolysins, exotoxins, resistance forms, plasmids, or lysogenic phages (Detilleux et al 1990;Moreno et al 2002). Several antigenic components of Brucella such as Omp16, Omp19, Omp25, Omp31, SurA, Dnak, trigger factor (TF), ribosomal protein L7L12, bacterioferritin (BFR) P39, and lumazine synthase BLS have been characterized (Barrionuevo and Giambartolomei 2019;Bundle et al 1989;Yin et al 2019). Efforts were instead concentrated on surface antigens (described as R in rough strain and A, M in smooth strains) and lipopolysaccharide (LPS) expected to trigger specific antibody response (Głowacka et al 2018;Jezi et al 2019;Mancilla 2016).…”