Evaluation of Protective Immunity of Peptide Vaccines Composed of a 15-mer N-terminal Matrix Protein 2 and a Helper T-Cell Epitope Derived from Influenza A Virus

The matrix protein 2 of influenza A virus (IFAV) has a relatively conserved ectodomain (M2e) composed of 23 amino acids, and M2e-based vaccines have been suggested to induce broad protective immunity in mice. In this study, we investigated whether N-terminal sequence of M2e (nM2e)-based vaccines with more conserved nM2e could induce influenza viral neutralizing activity. We constructed linear peptide vaccines with an nM2e sequence for PR8 virus (nM2Pr) connected to a probable 17-mer IFAV-derived helper T-cell epitope (ThE: T1, T2, or T3) at its N- or C-terminus. The peptide vaccines induced significant production of nM2e Abs regardless of either type or location of the ThE-epitope in BALB/c mice, while only T3 was effective in C57BL/6 mice. The Abs against nM2Pr-T3 elicited broader binding affinities to the nM2e peptides derived from various IFAVs than those against T3-nM2Pr. In addition, the nM2e-based vaccines efficiently protected the immunized mice from the lethal challenge of PR8 virus. These results suggest that the more conserved nM2e without cysteine will be useful for development of universal peptide vaccines than M2e.

Structure-activity relationships of anti-HIV-1 peptides with disulfide linkage between D- and L-cysteine at positions i and i+3, respectively, derived from HIV-1 gp41 C-peptide

The constrained alpha-helical structure of a C-peptide is useful for enhancing anti-HIV-1 activity. The i and i+3 positions in an alpha-helical structure are located close together, therefore D-Cys (dC) and L-Cys (C) were introduced at the positions, respectively, to make a dC-C disulfide bond in 28mer C-peptides. Accordingly, this study tested whether a dC-C disulfide bond would increase the alpha-helicity and anti-HIV-1 activity of peptides. A C-peptide can be divided into three domains, the N-terminal hydrophobic domain (HPD), middle interface domain (IFD), and C-terminal hydrogen domain (HGD), based on the binding property with an N-peptide. In general, the dC-C modifications in HPD enhanced the anti-HIV-1 activity, while those in IFD and HGD resulted in no or much less activity. The modified peptides with no activity clearly showed much less alpha-helicity than the native peptides, while those with higher activity showed an almost similar or slightly increased alpha-helicity. Therefore, the present results suggest that the introduction of a dC-C bridge in the N-terminal hydrophobic domain of a C-peptide may be useful for enhancing the anti-HIV-1 activity.

Evaluation of Differential Antigenic Properties of Selected B - cell Epitopes from the HIV - 1 p24 Protein using Synthetic Peptides / 대한면역학회지

The gag encoded p24 protein of human immunodeficiency virus-1 (HIV-1) is a major constitutent of the viral core, and is also known as one of the most immunodominant antigens in the host immune response against the HIV-1. Based on the neutralizing ability of anti-p24 antibodies as well as their rapid appearance in human serum after viral infection, the development of vaccines and diagnostic tools targeting the p24 protein and anti-p24 antibodies is of great interest. For the characterization of the immunological properties of the HIV-1 p24 protein, in a previous study, putative B-cell epitopes were identified by screening the reactivity of a goat anti-p24 antiserum to a large array of overlapping synthetic peptides covering the whole p24 sequence. Four peptides were identified for their abilities to elicit a strong B-cell response, which sequences comprises the regions p24 (164-182), (202-221), (217-236) and (232-256), respectively. In the present study, the immunogenicity and differential properties of each of these individual epitopes were further characterized. To evaluate the time course of the antibody response, BALB/c mice were immunized with the HIV-1 p24 protein and their serum titers against each of these peptides were determined. The earliest immune response was observed against the p24 (202-221) peptide, which also showed the highest antibody titer against the immunized antigen. Furthermore,. enzyme-linked immunosorbent assay with HIV-1 p24 protein coated microtiter plates revealed that anti-p24 (202-221) antiserum has the most pronounced reactivity against the native p24 protein. Since the p24 (202-221) epitope has also been reported to include a cytotoxic T-lymphocyte epitope, it is suggested that this region might represent a powerful antigenic site responsible for eliciting both T- and B-cell immune response. The possible application of this specific epitope in vaccine development or AIDS diagnosis is discussed.

Generation and characterization of a monoclonal antibody with high species-specificity to Schistosoma japonicum glutathione S-transferase

No abstract available.

Epitope Mapping of HIV1 gp41 Protein for Korean Anti - HIV1 Antisera using Synthetic Peptides / 대한면역학회지

The N-terminal sequence of HIV1 gp41 (amino acid residues 584-623) was known to be the immundominant region of HIV1 gp41 protein. In order to determine epitope for gp41 protein of Korean anti-HIV1 positive sera, multiple antigenic peptides (MAPs) for the sequences corresponding to 584-604, 590-612, 604-623 and 584-618 of HIV1 gp41 were synthesized by solid phase method using Fmoc-Lys (Fmoc)-OH and used as coating antigens for ELISA. The reactivities of the synthetic peptides with Korean HIV1 positive (21 samples) and anti-HIV1 negative sera (22 samples) obtained from healthy blood doner were estimated by an indirect ELISA. MAPs for 584-604, 590-612 and 604-623 of gp41 reacted with 62 %, 100 % and 81 % of Korean anti-HIV1 positive sera tested, respectively. The results suggest that the epitope for HIV1 gp 41 for Korean anti-HIV1 positive sera is located in the region of amino acid 590-612 of gp41. MAP for gp41 (584-618) reacted with all (100 %) of anti-HIV1 positive sera tested, but did not react with anti-HlV1 negative sera. In addition, this MAP reacted stronger with seven samples of anti-HIV1 positive sera of anti-HIV1/2 combo performance panel than the mixture of 584-604, 590-612 and 604-623 of gp41, but did not react with anti-HIV negative serum. The high sensitivity and selectivity of MAP of gp41 (584-618) suggest that this peptide as a coating antigen in an ELISA system will be useful for antibody detection of HIV1.