Characterization of Inhibitory Anti-Duffy Binding Protein II Immunity: Approach to Plasmodium vivax Vaccine Development in Thailand

Plasmodium vivax Duffy binding protein region II (DBPII) is an important vaccine candidate for antibody-mediated immunity against vivax malaria. A significant challenge for vaccine development of DBPII is its highly polymorphic nature that alters sensitivity to neutralizing antibody responses. Here, we aim to characterize naturally-acquired neutralizing antibodies against DBPII in individual Thai residents to give insight into P. vivax vaccine development in Thailand. Anti-DBPII IgG significantly increased in acute vivax infections compared to uninfected residents and naive controls. Antibody titers and functional anti-DBPII inhibition varied widely and there was no association between titer and inhibition activity. Most high titer plasmas had only a moderate to no functional inhibitory effect on DBP binding to erythrocytes, indicating the protective immunity against DBPII binding is strain specific. Only 5 of 54 samples were highly inhibitory against DBP erythrocyte-binding function. Previously identified target epitopes of inhibitory anti-DBPPII IgG (H1, H2 and H3) were localized to the dimer interface that forms the DARC binding pocket. Amino acid polymorphisms (monomorphic or dimorphic) in H1 and H3 protective epitopes change sensitivity of immune inhibition by alteration of neutralizing antibody recognition. The present study indicates Thai variant H1.T1 (R308S), H3.T1 (D384G) and H3.T3 (K386N) are the most important variants for a DBPII candidate vaccine needed to protect P. vivax in Thai residents

Plasmodium vivax Invasion of Human Erythrocytes Inhibited by Antibodies Directed against the Duffy Binding Protein

Christopher King and colleagues found that both rabbit and human antibodies inhibited binding of rPvDBPII to the Duffy antigen N-terminal region and to Duffy-positive human erythrocytes, suggesting that a PvDBP-based vaccine may reduce blood stage Plasmodium vivax infection

Skin Anti-Aging Potential of Ipomoea pes-caprae Ethanolic Extracts on Promoting Cell Proliferation and Collagen Production in Human Fibroblasts (CCD-986sk Cells)

Collagen loss in the skin dermis is a major cause of age-related changes to the skin. Natural phytochemical substances are desirable for the prevention of skin aging and the formation of wrinkles. Ipomoea pes-caprae (IPC) has been utilized for nutritional and therapeutic purposes, and its extract contains collagenase inhibitory activity while causing no cytotoxicity. The purpose of this study was to examine the impact of IPC extracts on cell proliferation and collagen production in human fibroblasts (CCD-986sk cells). IPC leaves were macerated in 70% and 95% ethanol and the chemical composition of the resulting extracts (IPC70 and IPC95) were determined using high performance liquid chromatography (HPLC). The bioactivity of IPC extracts was examined in CCD-986sk cells, including antioxidant capacity, inhibition of collagenase, effects on cell proliferation and collagen production, as well as wound healing using an in vitro scratch test. Changes in expression of collagen type I (COL1A1), tumor growth factor beta 1 (TGFB1), and beta-fibroblast growth factor (FGF2) genes were also evaluated. The antioxidant and collagenase inhibitory properties of IPC extracts were associated with 3,5-di-caffeoylquinic acid, chlorogenic acid, and ferulic acid. IPC extracts at noncytotoxic concentrations significantly increased cell proliferation, collagen production, and wound healing. These effects appear linked to the upregulation of COL1A1, TGFB1, and FGF2 genes. The bioactivity of the IPC70 extract was greater than that for IPC95. This is useful in cosmeceutical applications for human skin aging. Our findings indicate that IPC extracts have the potential for use in skin anti-aging cosmeceutical preparations

Phosphoproteomic analysis of apoptotic hematopoietic stem cells from hemoglobin E/β-thalassemia

<p>Abstract</p> <p>Background</p> <p>Hemoglobin E/β-thalassemia is particularly common in Southeast Asia and has variable symptoms ranging from mild to severe anemia. Previous investigations demonstrated the remarkable symptoms of β-thalassemia in terms of the acceleration of apoptotic cell death. Ineffective erythropoiesis has been studied in human hematopoietic stem cells, however the distinct apoptotic mechanism was unclear.</p> <p>Methods</p> <p>The phosphoproteome of bone marrow HSCs/CD34⁺cells from HbE/β-thalassemic patients was analyzed using IMAC phosphoprotein isolation followed by LC-MS/MS detection. Decyder MS software was used to quantitate differentially expressed proteins in 3 patients and 2 normal donors. The differentially expressed proteins from HSCs/CD34⁺cells were compared with HbE/β-thalassemia and normal HSCs.</p> <p>Results</p> <p>A significant change in abundance of 229 phosphoproteins was demonstrated. Importantly, the analysis of the candidate proteins revealed a high abundance of proteins that are commonly found in apoptotic cells including cytochrome C, caspase 6 and apoptosis inducing factors. Moreover, in the HSCs patients a significant increase was observed in a specific type of phosphoserine/threonine binding protein, which is known to act as an important signal mediator for the regulation of cell survival and apoptosis in HbE/β-thalassemia.</p> <p>Conclusions</p> <p>Our study used a novel method to investigate proteins that influence a particular pathway in a given disease or physiological condition. Ultimately, phosphoproteome profiling in HbE/β-thalassemic stem cells is an effective method to further investigate the cell death mechanism of ineffective erythropoiesis in β-thalassemia. Our report provides a comprehensive phosphoproteome, an important resource for the study of ineffective erythropoiesis and developing therapies for HbE/β-thalassemia.</p

Anti-DBPII response and DBPII-Duffy positive erythrocyte inhibitory.

<p>Scatter plot showing the correlation between anti-DBPII levels and inhibition activity among Thai vivax residents (Spearman's coefficient: 0.042; P = 0.764). Fifty-four samples (1∶200 diluted plasma) were tested for their reactivity to DBPII in standard ELISA procedure and for the inhibition function of DBPII binding to Duffy positive erythrocyte measured by COS7 cell erythrocyte binding assay.</p

Naturally acquired anti-DBPII responses and their inhibition efficiency against DBPII binding.

a<p>High responder (HR), Low responder (LR), Non-responder (NR).</p

The synthesized peptides using in antibody purification and testing functional inhibition.

<p>H1, H2 and H3 are target epitopes of naturally acquired inhibitory antibodies <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0035769#pone.0035769-Chootong1" target="_blank">[25]</a>. H1.T1, H3.T1, H3.T2, H3.T3 and M3.T1 epitopes are the variant strain among Thai vivax isolates <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0035769#pone.0035769-Gosi1" target="_blank">[19]</a>. NI is the target epitopes of non-inhibitory antibodies.</p