World Journal of Microbiology and Biotechnology (2018) 34:82
Serological diagnosis of Mycoplasma pneumoniae infection by using
the mimic epitopes
· Lanhua Zhao
· Shengtao Li
· Guizhen Xu
· Yanhua Zeng
Received: 11 February 2018 / Accepted: 27 May 2018 / Published online: 29 May 2018
© Springer Science+Business Media B.V., part of Springer Nature 2018
Nowadays, there is lack of eﬀective serological detection method for Mycoplasma pneumoniae (M. pneumoniae) infection
in clinic. In this study, the mimic epitopes of M. pneumoniae were screened to evaluate the role in the serodiagnosis of M.
pneumoniae infection. The M. pneumoniae-positive serum was used as the target for biopanning to phage display random
7-peptide library. The positive phage clones were selected and the DNA were sequenced and analyzed by BLAST. The rep-
resentative phages were identiﬁed using dot immunoblotting and ELISA. The exogenous heptapeptides were synthesized and
their reactions with M. pneumonia-positive serum were tested by indirect ELISA. Two heptapeptides, namely heptapeptide
1: TVNFKLY and heptapeptide 2: LPQRLRT, were screened out from the randomly selected 40 phages after the four bio-
panning rounds. They had high homologies to some M. pneumoniae antigens. Besides, the representative bacteriophage
containing heptapeptide 1 or 2 could react with the M. pneumonia- positive serum. The sensitivities of heptapeptide 1 and
heptapeptide 2 for the diagnosis of M. pneumoniae infection were 90.1 and 80.0%, respectively, and the speciﬁcities were
94.3 and 97.1%, respectively. Therefore the two heptapeptides were the mimic epitopes of M. pneumoniae and might have
potential serological diagnosis value for M. pneumoniae infection.
Keywords Heptapeptides · Mycoplasma pneumoniae · Mimic epitopes · Serological diagnosis
Mycoplasma pneumoniae (M. pneumoniae) is a very small
prokaryote microorganism in the class Mollicutes and it
commonly causes infections of the respiratory system (Diaz
and Winchell 2016). Generally, M. pneumoniae is of high
contagiousness, especially in children, and it is the main
pathogen of community-acquired pneumonia (Inchley et al.
2017). But till now, its early diagnosis is diﬃcult because of
its few unusual symptoms. Thus, early diagnosis of M. pneu-
moniae infection is of extreme importance (Herrera et al.
2016). At present, the diagnosis methods of M.pneumoniae
infection mainly include isolation and culture, serological
detection (Lee et al. 2017), PCR detection (Li et al. 2017)
and physical diagnosis (Kishaba 2016). And there is still
lack of high sensitivity of speciﬁc antigens for serological
diagnosis of M.pneumoniae infection (Wang et al. 2017).
Studies have used the C-terminal of the P1 protein of M.
pneumoniae, predicted by bioinformatics, as an antigen
for serological diagnosis (Xue et al. 2013; Chourasia et al.
2014). Widjaja et al. demonstrate that P90 and P40 are main
adherence-accessory protein of Mycoplasma Pneumonia,
which may be the potential diagnostic antigens (Widjaja
et al. 2015). In addition, the N-terminal of P30 protein con-
tains important epitopes (Chang et al. 2011). However, the
traditional protein expression and puriﬁcation methods used
in these studies are often of cumbersome operation and high
cost, but always of low speciﬁcity.
The key sites of antigens for antibodies binding are domi-
nant epitopes or functional epitopes, which generally contain
only 5–7 amino acids or monosaccharide residues (Chen and
Wenyuan Shi and Lanhua Zhao have contributed equally to this
* Yanhua Zeng
Department of Clinical Laboratory, Chenzhou First
People’s Hospital, Institute of Translational Medicine,
University of South China, Chenzhou 423000,
People’s Republic of China
Institute of Pathogenic Biology, School of Medicine,
University of South China, No. 28, West Changsheng
Road, Zhengxiang District, Hengyang 421001,
People’s Republic of China