• Bulletin of the Korean Chemical Society
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• v.32 no.9
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• pp.3425-3428
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• 2011

Apolipoprotein A-I (Apo A-I) is a major component for high density lipoproteins (HDL). A number of mimetic peptides of Apo A-I were screened from the phase-displayed random peptide library by utilizing monoclonal antibodies (A12). Mimetic peptide for A12 epitope against Apo A-I was selected as CPFARLPVEHHDVVGL (pA1). From the BLAST search, the mimetic peptide pA1 had 40% homology with Apo A-I. As a result of the structural determination of this mimotope using homo/hetero nuclear 2D-NMR techniques and NMR-based distance geometry (DG)/molecular dynamic (MD) computations, DG structure had low penalty value of 0.3-0.7 ${\AA}^2$ and the total RMSD was 0.6-1.6 ${\AA}$. The mimotope pA1 exhibited characteristic conformation including a ${\beta}$-turn from Pro[7] to His[11].

• BMB Reports
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• v.38 no.3
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• pp.290-293
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• 2005

In order to investigate the epitope of basic fibroblast growth factor (bFGF) and its immunogenicity, the epitopes of bFGF were screened from the phage display library with monoclonal antibody GF22, which can neutralize the bio-activity of bFGF. By three rounds of screening, the positive phage clones with bFGF epitopes were selected, which can effectively block the bFGF to bind with GF22. Sequence analysis showed that the epitopes shared a highly conservative sequence (Leu-Pro-Pro/Leu-Gly-His-Phe/Ile-Lys). The sequence of PPGHFK was located at 22-27 of the bFGF. The specific immuno-response of mouse could be highly induced by phage clones with the epitopes. And the anti-bFGF activity induced by LPGHFK was 3 times higher than the original sequence, which showed that the mimetic peptide LPLGHIK might be used as a tumor vaccine in the prevention and treatment of tumor.

• Biomedical Science Letters
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• v.13 no.4
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• pp.325-332
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• 2007

Cell-mediated immune response (CMI) is a major immune protective mechanism against tuberculosis (TB) infection. Among several components involved in CMI, recent studies suggest that CD8+ T cells are important in controlling TB infection. In our previous report, we defined four Mycobacterium tuberculosis (MTB) derived epiotpe peptides specific for HLA-A*0201-restricted CD8+ T cells. These four peptides are $PstAl_{75-83}$, $ThyA_{30-38}$, $RpoB_{127-135}$ and $85B_{15-23}$. In this study, these epitope peptides specific CD8+ T cell responses in tuberculous pleurisy were investigated using ex vivo $IFN-\gamma$ elispot assay and intracellular $IFN-\gamma$ staining method. As a result, we observed these epitope peptide specific CD8+ T cell responses are induced in all three patients with tuberculous pleurisy suggesting that CD8+ T cells are involved in protective immune mechanism against MTB infection in tuberculous pleurisy. However, the CMI to mitogens and MTB antigens from pleural fluids of patients with tuberculous pleurisy does not seem to correlate with that from peripheral blood, although the sample size is too small to make any conclusion. In sum, the MHC I restricted CD8+ T cell responses seem to be induced efficiently in the pleural fluids, at the site of TB infection, in which the CMI is actively induced. In addition, these experiments suggest that MHC I restricted CD8+ T cell mediated immune responses are also involved in protective mechanism against MTB infection in extra-pulmonary TB.

• International Journal of Oral Biology
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• v.45 no.4
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• pp.211-217
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• 2020

Molecular mimicry is the most common mechanism that breaches self-tolerance. We previously identified autoantibodies to aquaporin-5 (AQP5) in the sera of patients with Sjögren's syndrome and found that the aquaporin of Prevotella melaninogenica (PmAqp), an oral commensal, is highly homologous to human AQP5. This study aimed to test whether PmAqp can induce anti-AQP5 autoantibodies via molecular mimicry. From the amino acid sequence of PmAqp, an immunizing peptide; i.e., PmE-L, was designed, which contained both the B cell epitope "E" and T cell epitope. C57BL/6 and BALB/c mice were subcutaneously immunized with linear or cyclic forms of PmE-L emulsified in incomplete Freund's adjuvant. The concentrations of the antibodies in sera were measured using enzyme-linked immunosorbent assays. Both linear and cyclic PmE-L induced high levels of antibodies against not only the immunized peptides but also autoantibodies against AQP5E and antibodies against PmE, a Pm homolog of AQP5E. In C57BL/6 mice; however, the cyclic form of PmE-L was more efficient than the linear form in inducing autoantibodies against AQP5E that contained a cyclic epitope. The levels of anti-PmE antibodies and anti-AQP5E autoantibodies showed a strong positive correlation (r = 0.95, p < 0.0005), suggesting molecular mimicry. Collectively, the mice produced anti-AQP5E autoantibodies in response to a PmAqp-derived peptide. This model proved to be useful for studying the mechanisms of autoantibody production by molecular mimicry.

• Journal of Periodontal and Implant Science
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• v.33 no.4
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• pp.543-553
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• 2003

Due to considerably high degree of sequence homology between bacterial and human heat shock proteins(hsp), it has been widely thought that this protein might be involved in autoimmune disease mechanisms in humans. To elucidate how stress proteins contribute in the immunopathogenesis of periodontitis, the present study was performed to evaluate the T cell immune responses specific to Porphyromonas gingivalis (P. gingivalis) heat shock protein (hsp)60 and T-cell epitope specificities for P. gingivalis hsp60 in periodontitis. Anti-P. gingivalis IgG antibody titers were elevated in all patients. We could establish P. gingivalis hsp-specific T cell ines from the peripheral blood of peridontitis, a mixture of $CD4^+$ and $CD8^+$ cells. Of 108 overlapping synthetic peptides spanning whole P. gingivalis hsp60 moleculc, ten peptides with cpitopes specifities for T-cell were showed. Interestingly, ten epitopes were also identified as T-cell epitopes in the present study as well as B-cell epitopes in peridontitis. Therefore, all the ten representative epitopes were designated as common T-and B-cell epitopes for peridontitis. It is critical in developing a peptide vaccine strategy for potential prevention of periodontitis. It was concluded that P. gingivalis hsp60 might be involved in the immunoregulatory process of periodontitis with heat shock protein specificities.

• BMB Reports
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• v.44 no.9
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• pp.607-612
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• 2011

Several investigators have shown that CpG-DNA has outstanding effects as a Th1-responsive adjuvant and that its potent adjuvant effects are enhanced by encapsulation with a liposome of proper composition. In this study, we showed that encapsulation with phosphatidyl-${\beta}$-oleoyl-${\gamma}$-palmitoyl ethanolamine (DOPE): cholesterol hemisuccinate (CHEMS) complex enhances the immunostimulatory activity of CpG DNA and the binding of CpG-DNA to TLR9. We also examined involvement of myeloid differentiation protein (MyD88) and NF-${\kappa}B$ activation in liposome-encapsulated CpG-DNA-induced IL-8 promoter activation. In this manuscript, the natural phosphodiester bond CpG-DNA encapsulated by DOPE : CHEMS complex is designated as Lipoplex(O). Importantly, we successfully screened B cell epitopes of envelope protein (E protein) of hepatitis C virus (HCV-E) and attachment glycoprotein G of human respiratory syncytial virus (HRSV-G) by immunization with complexes of several peptides and Lipoplex(O) without carriers. Therefore, Lipoplex(O) is potentially applicable as a universal adjuvant for peptide-based epitope screening and antibody production.

• Bulletin of the Korean Chemical Society
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• v.32 no.11
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• pp.4016-4020
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• 2011

A number of mimetic peptides of apolipoprotein A-I, a major component for high density lipoproteins (HDL), were screened from the phase-displayed random peptide library by utilizing monoclonal antibodies (A12). A mimetic peptide for A12 epitope against apolipoprotein A-I was selected as FVLVRDTFPSSVCCP(pA2) exhibiting 45% homology with Apo A-I in the BLAST search. Solution structure determination of this mimotope was made by using 2D-NMR data and NMR-based distance geometry (DG)/molecular dynamic calculations. The resulting DG structures had low penalty value of 0.4-0.6 ${\AA}^2$ and the total RMSD of 0.7-1.7 ${\AA}$. The mimotope pA2 exhibited a characteristic ${\beta}$-turn conformation from Val[2] to Phe[8] near Pro[9] residue.

• Journal of Periodontal and Implant Science
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• v.40 no.2
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• pp.61-68
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• 2010

Purpose: The present study was performed to clarify the relationship between periodontal disease severity and selected immunological parameters consisting of serum IgG titer against periodontopathogenic bacteria, the expression of the helper T-cell cytokine by gingival mononuclear cells, and patients' immunoreactivity to cross-reactive heat shock protein (HSP) epitope peptide from P. gingivalis HSP60. Methods: Twenty-five patients with moderate periodontitis had their gingival connective tissue harvested of gingival mononuclear cells during an open flap debridement procedure and peripheral blood was drawn by venipuncture to collect serum. The mean level of interproximal alveolar bone was calculated to be used as an index for periodontal disease severity for a given patient. Each of selected immunologic parameters was subject to statistical management to seek their correlations with the severity of periodontal disease. Results: A significant correlation could not be identified between serum IgG titers against specific bacteria (Porphyromonas gingivalis, Prevotella intermedia, Fusobacterium nucleatum, Actinobacillus actinomycetemcomitans, and Streptococcus mutans) and the severity of periodontal disease. Expression of interleukin (IL)-10 by gingival mononuclear cells was statistically significant in the group of patients who had higher levels of alveolar bone height. However, a similar correlation could not be demonstrated in cases for IL-4 or interferon-$\gamma$. Patients' serum reactivity to cross-reactive epitope peptide showed a significant correlation with the amount of alveolar bone. Conclusions: It was concluded that expression of IL-10 by gingival mononuclear cells and patients' sero-reactivity to the cross-reactive HSP peptide of P. gingivalis HSP60 were significantly correlated with alveolar bone height.

• Asian Pacific Journal of Cancer Prevention
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• v.14 no.12
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• pp.7335-7338
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• 2013

There is increasing evidence that natural killer (NK) cells play an important role in antitumor immunity following dendritic cell (DC) vaccination. Little is known, however, about the optimal stimulation of DCs by epitopes and NK interactions for cytotoxicity in tumors. In this study, DC cells activated by the HPV16E7.49-57 epitope and LPS were co-cultured with NK cells in vitro, and then used ot immunize mice to study CTL activity of TC-1, which constitutively expresses HPV16E6E7, with an LDH release assay. Cytotoxicity in mice immunized with DC loaded with epitope HPVE7.49-57 vaccine co-cultured with NK was enhanced significantly (p<0.01). In conclusion, talk-across between DC and NK cells enhances their functions, also improving cytotoxicity againsttumor cells, suggesting that activated DC-NK by epitopes has potential application for cancer-specific immuno-cellular therapy.

• IMMUNE NETWORK
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• v.21 no.5
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• pp.34.1-34.16
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• 2021

Sjögren's syndrome (SS) is an autoimmune disease characterized by dryness of the mouth and eyes. The glandular dysfunction in SS involves not only T cell-mediated destruction of the glands but also autoantibodies against the type 3 muscarinic acetylcholine receptor or aquaporin 5 (AQP5) that interfere with the secretion process. Studies on the breakage of tolerance and induction of autoantibodies to these autoantigens could benefit SS patients. To break tolerance, we utilized a PmE-L peptide derived from the AQP5-homologous aquaporin of Prevotella melaninogenica (PmAqp) that contained both a B cell "E" epitope and a T cell epitope. Repeated subcutaneous immunization of C57BL/6 mice with the PmE-L peptide efficiently induced the production of Abs against the "E" epitope of mouse/human AQP5 (AQP5E), and we aimed to characterize the antigen specificity, the sequences of AQP5E-specific B cell receptors, and salivary gland phenotypes of these mice. Sera containing anti-AQP5E IgG not only stained mouse Aqp5 expressed in the submandibular glands but also detected PmApq and PmE-L by immunoblotting, suggesting molecular mimicry. Characterization of the AQP5E-specific autoantibodies selected from the screening of phage display Ab libraries and mapping of the B cell receptor repertoires revealed that the AQP5E-specific B cells acquired the ability to bind to the Ag through cumulative somatic hypermutation. Importantly, animals with anti-AQP5E Abs had decreased salivary flow rates without immune cell infiltration into the salivary glands. This model will be useful for investigating the role of anti-AQP5 autoantibodies in glandular dysfunction in SS and testing new therapeutics targeting autoantibody production.