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Chimeric peptide constructs comprising linear B-cell epitopes: application to the serodiagnosis of infectious diseases.

Lu Y, Li Z, Teng H, Xu H, Qi S, He J, Gu D, Chen Q, Ma H - Sci Rep (2015)

Bottom Line: However, the long-predicted diagnostic value of epitopes has not been realized.Using DEIFS for malaria, we identified 6 epitopes from 8 peptides and combined them into 3 chimeric peptide constructs.In addition to applications in diagnosis, DEIFS could also be used in the diagnosis of virus and bacterium infections, discovery of vaccine candidates, evaluation of vaccine potency, and study of disease progression.

View Article: PubMed Central - PubMed

Affiliation: Nano-Bio-Chem Centre, Suzhou Institute of Nano-Tech and Nano-Bionics, Chinese Academy of Sciences, Suzhou, 215123, P. R. China.

ABSTRACT
Linear B-cell epitopes are ideal biomarkers for the serodiagnosis of infectious diseases. However, the long-predicted diagnostic value of epitopes has not been realized. Here, we demonstrated a method, diagnostic epitopes in four steps (DEIFS), that delivers a combination of epitopes for the serodiagnosis of infectious diseases with a high success rate. Using DEIFS for malaria, we identified 6 epitopes from 8 peptides and combined them into 3 chimeric peptide constructs. Along with 4 other peptides, we developed a rapid diagnostic test (RDT), which is able to differentiate Plasmodium falciparum (P. falciparum) from Plasmodium vivax (P. vivax) infections with 95.6% overall sensitivity and 99.1% overall specificity. In addition to applications in diagnosis, DEIFS could also be used in the diagnosis of virus and bacterium infections, discovery of vaccine candidates, evaluation of vaccine potency, and study of disease progression.

No MeSH data available.


Related in: MedlinePlus

Biomarkers for serodiagnosis.Both antigen and antibodies can be the target of detection. (a) P. falciparum specific antigen can be detected by sandwiched immunoassay to indicate infection. (b) Epitopes are immunodominant regions of antigen protein, which can interact with antibodies. Antigens were divided into overlapped peptides (30 amino acids in length with 15 amino acids overlapped), which were printed on iPDMS membranes to form microarrays. (c) A heat map of 304 serums (179 P. falciparum infected, 125 healthy) to 2038 peptides was obtained by directly converting SNR to grayscale. (d) In large-scale seroscreening, specific antibodies-epitope interactions resulted in high signal intensity region on the heat map. (e) Representative result from P. falciparum infected serum. (f) Representative result from healthy serum.
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f2: Biomarkers for serodiagnosis.Both antigen and antibodies can be the target of detection. (a) P. falciparum specific antigen can be detected by sandwiched immunoassay to indicate infection. (b) Epitopes are immunodominant regions of antigen protein, which can interact with antibodies. Antigens were divided into overlapped peptides (30 amino acids in length with 15 amino acids overlapped), which were printed on iPDMS membranes to form microarrays. (c) A heat map of 304 serums (179 P. falciparum infected, 125 healthy) to 2038 peptides was obtained by directly converting SNR to grayscale. (d) In large-scale seroscreening, specific antibodies-epitope interactions resulted in high signal intensity region on the heat map. (e) Representative result from P. falciparum infected serum. (f) Representative result from healthy serum.

Mentions: For the first step of DEIFS, 38 P. falciparum proteins (Fig. 2b and Extended Data Table 1) were selected and divided into 2038 overlapped peptides for candidate library construction. These 2038 overlapped peptides were printed on iPDMS membrane to form a microarray chip for the second step of DEIFS, a two-round seroscreening, which was conducted for a training group (125 healthy and 289 P. falciparum-infected serum). The iPDMS membrane provides a near “zero” background for serological assays, even without blocking treatment (Fig. 2e,f). With this unique feature, the data acquisition and analysis were simple20 (Extended Data Fig. 2): chemiluminescence intensity was captured by a CCD camera for each dot of the microarray, which was then converted to the signal to noise ratio (SNR). These original data could be used to conduct the following bioinformatics analysis. Thus, we solved the first problem: technical difficulties in the large-scale seroscreening of peptide microarrays. The solution for the second problem was using multiple proteins, as demonstrated below, by which one could obtain enough epitopes for diagnosis.


Chimeric peptide constructs comprising linear B-cell epitopes: application to the serodiagnosis of infectious diseases.

Lu Y, Li Z, Teng H, Xu H, Qi S, He J, Gu D, Chen Q, Ma H - Sci Rep (2015)

Biomarkers for serodiagnosis.Both antigen and antibodies can be the target of detection. (a) P. falciparum specific antigen can be detected by sandwiched immunoassay to indicate infection. (b) Epitopes are immunodominant regions of antigen protein, which can interact with antibodies. Antigens were divided into overlapped peptides (30 amino acids in length with 15 amino acids overlapped), which were printed on iPDMS membranes to form microarrays. (c) A heat map of 304 serums (179 P. falciparum infected, 125 healthy) to 2038 peptides was obtained by directly converting SNR to grayscale. (d) In large-scale seroscreening, specific antibodies-epitope interactions resulted in high signal intensity region on the heat map. (e) Representative result from P. falciparum infected serum. (f) Representative result from healthy serum.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4543967&req=5

f2: Biomarkers for serodiagnosis.Both antigen and antibodies can be the target of detection. (a) P. falciparum specific antigen can be detected by sandwiched immunoassay to indicate infection. (b) Epitopes are immunodominant regions of antigen protein, which can interact with antibodies. Antigens were divided into overlapped peptides (30 amino acids in length with 15 amino acids overlapped), which were printed on iPDMS membranes to form microarrays. (c) A heat map of 304 serums (179 P. falciparum infected, 125 healthy) to 2038 peptides was obtained by directly converting SNR to grayscale. (d) In large-scale seroscreening, specific antibodies-epitope interactions resulted in high signal intensity region on the heat map. (e) Representative result from P. falciparum infected serum. (f) Representative result from healthy serum.
Mentions: For the first step of DEIFS, 38 P. falciparum proteins (Fig. 2b and Extended Data Table 1) were selected and divided into 2038 overlapped peptides for candidate library construction. These 2038 overlapped peptides were printed on iPDMS membrane to form a microarray chip for the second step of DEIFS, a two-round seroscreening, which was conducted for a training group (125 healthy and 289 P. falciparum-infected serum). The iPDMS membrane provides a near “zero” background for serological assays, even without blocking treatment (Fig. 2e,f). With this unique feature, the data acquisition and analysis were simple20 (Extended Data Fig. 2): chemiluminescence intensity was captured by a CCD camera for each dot of the microarray, which was then converted to the signal to noise ratio (SNR). These original data could be used to conduct the following bioinformatics analysis. Thus, we solved the first problem: technical difficulties in the large-scale seroscreening of peptide microarrays. The solution for the second problem was using multiple proteins, as demonstrated below, by which one could obtain enough epitopes for diagnosis.

Bottom Line: However, the long-predicted diagnostic value of epitopes has not been realized.Using DEIFS for malaria, we identified 6 epitopes from 8 peptides and combined them into 3 chimeric peptide constructs.In addition to applications in diagnosis, DEIFS could also be used in the diagnosis of virus and bacterium infections, discovery of vaccine candidates, evaluation of vaccine potency, and study of disease progression.

View Article: PubMed Central - PubMed

Affiliation: Nano-Bio-Chem Centre, Suzhou Institute of Nano-Tech and Nano-Bionics, Chinese Academy of Sciences, Suzhou, 215123, P. R. China.

ABSTRACT
Linear B-cell epitopes are ideal biomarkers for the serodiagnosis of infectious diseases. However, the long-predicted diagnostic value of epitopes has not been realized. Here, we demonstrated a method, diagnostic epitopes in four steps (DEIFS), that delivers a combination of epitopes for the serodiagnosis of infectious diseases with a high success rate. Using DEIFS for malaria, we identified 6 epitopes from 8 peptides and combined them into 3 chimeric peptide constructs. Along with 4 other peptides, we developed a rapid diagnostic test (RDT), which is able to differentiate Plasmodium falciparum (P. falciparum) from Plasmodium vivax (P. vivax) infections with 95.6% overall sensitivity and 99.1% overall specificity. In addition to applications in diagnosis, DEIFS could also be used in the diagnosis of virus and bacterium infections, discovery of vaccine candidates, evaluation of vaccine potency, and study of disease progression.

No MeSH data available.


Related in: MedlinePlus