AUTHOR=Ji Xingzhao , Sun Na Li , Hou Xin Xue , Xu Shuai , Qiu Tong Xiao , Tang Lu , Li Qiao He , Wang Bing Xue , Li Jun Zhen 

TITLE=Screening and Identification of B-Cell Epitopes in the P61 Protein of Nocardia brasiliensis

JOURNAL=Frontiers in Cellular and Infection Microbiology

VOLUME=8

YEAR=2018

URL=https://www.frontiersin.org/journals/cellular-and-infection-microbiology/articles/10.3389/fcimb.2018.00224

DOI=10.3389/fcimb.2018.00224

ISSN=2235-2988

ABSTRACT=<p>The P61 protein is an immunodominant antigen of <italic>Nocardia brasiliensis</italic> that is observed in the sera from patients infected with the bacterium. However, the B-cell epitopes of <italic>N. brasiliensis</italic> are still unresolved. To identify the antigenic determinants of P61, we screened seven monoclonal antibodies (mAbs) against P61 protein that was expressed in the <italic>Escherichia coli</italic> system. A series of truncated peptides of P61 were then generated and the mAbs were used to screen these peptides by Western blot analyses. Three B-cell epitopes were recognized by the P61 specific mAbs: 461-FEYWTKVDPEIGKRIEEG-478, 427-LVREVFNDAQRDRLVSNVVGGVQEPV. LSRVFEYWTKVDPEIGKRIEEGVRAG-482, and 447-HVLGGVQEPVLSRVFEY WTKVDPEI GKRIEEGVRAGLD-484. The latter two epitopes were further identified by <italic>N. brasiliensis</italic>-infected mouse serum. These results facilitate future investigations of serodiagnostic methods to identify <italic>Nocardia</italic> infections.</p>