Immunization with PfGBP130 generates antibodies that inhibit RBC invasion by P. falciparum parasites

BackgroundDespite decades of effort, Plasmodium falciparum malaria remains a leading killer of children. The absence of a highly effective vaccine and the emergence of parasites resistant to both diagnosis as well as treatment hamper effective public health interventions.Methods and resultsTo discover new vaccine candidates, we used our whole proteome differential screening method and identified PfGBP130 as a parasite protein uniquely recognized by antibodies from children who had developed resistance to P. falciparum infection but not from those who remained susceptible. We formulated PfGBP130 as lipid encapsulated mRNA, DNA plasmid, and recombinant protein-based immunogens and evaluated the efficacy of murine polyclonal anti-PfGBP130 antisera to inhibit parasite growth in vitro. Immunization of mice with PfGBP130-A (aa 111–374), the region identified in our differential screen, formulated as a DNA plasmid or lipid encapsulated mRNA, but not as a recombinant protein, induced antibodies that inhibited RBC invasion in vitro. mRNA encoding the full ectodomain of PfGBP130 (aa 89–824) also generated parasite growth-inhibitory antibodies.ConclusionWe are currently advancing PfGBP130-A formulated as a lipid-encapsulated mRNA for efficacy evaluation in non-human primates

Schistosoma japonicum soluble egg antigens attenuate invasion in a first trimester human placental trophoblast model.

Schistosomiasis affects nearly 40 million women of reproductive age, and is known to elicit a pro-inflammatory signature in the placenta. We have previously shown that antigens from schistosome eggs can elicit pro-inflammatory cytokine production from trophoblast cells specifically; however, the influence of these antigens on other characteristics of trophoblast function, particularly as it pertains to placentation in early gestation, is unknown. We therefore sought to determine the impact of schistosome antigens on key characteristics of first trimester trophoblast cells, including migration and invasion.First trimester HTR8/SVneo trophoblast cells were co-cultured with plasma from pregnant women with and without schistosomiasis or schistosome soluble egg antigens (SEA) and measured cytokine, cellular migration, and invasion responses.Exposure of HTR8 cells to SEA resulted in a pro-inflammatory, anti-invasive signature, characterized by increased pro-inflammatory cytokines (IL-6, IL-8, MCP-1) and TIMP-1. Additionally, these cells displayed 62% decreased migration and 2.7-fold decreased invasion in vitro after treatment with SEA. These results are supported by increased IL-6 and IL-8 in the culture media of HTR8 cells exposed to plasma from Schistosoma japonica infected pregnant women.Soluble egg antigens found in circulation during schistosome infection increase pro-inflammatory cytokine production and inhibit the mobility and invasive characteristics of the first trimester HTR8/SVneo trophoblast cell line. This is the first study to assess the impact of schistosome soluble egg antigens on the behavior of an extravillous trophoblast model and suggests that schistosomiasis in the pre-pregnancy period may adversely impact placentation and the subsequent health of the mother and newborn

The Use of Streptolysin O for the Treatment of Scars, Adhesions and Fibrosis: Initial Investigations Using Murine Models of Scleroderma

Diseases and conditions involving the deposition of excessive amounts of collagen include scleroderma, fibrosis, and scar and surgical adhesion formation. Diseases such as scleroderma may result from acute and chronic inflammation, disturbances in the normal parenchymal area, and activation of fibroblasts. ML-05, a modified form of the hemolytic and cytotoxic bacterial toxin, streptolysin O, is being developed for the treatment of such collagen-related disorders. At sublytic concentrations in vitro, ML-05 was shown to activate CD44 expression. This may modulate production of collagen, hyaluronate, and their associated enzymes to allow a restoration of normal extracellular matrices within tissues. More importantly, ML-05 appeared to decrease skin collagen levels in two in vivo models of collagen disorders, the tight skin mouse (Tsk) model of scleroderma, and the bleomycin-induced mouse skin fibrosis model. In the Tsk model, levels of hydroxyproline (a measure of total collagen) decreased by 25% in the Tsk+ML-05 treatment group relative to the Tsk+saline control group over a 3-month period. In the bleomycin-induced skin fibrosis study, hydroxyproline levels decreased from 15–22% over a 6-week period in a bleomycin-induced ML-05 treatment group (relative to levels in a bleomycin-induced, untreated control group). Hydroxyproline levels in samples from this treatment group were only slightly greater than levels in an uninduced control group at 8 weeks. Thus, ML-05 treatment appeared to reduce collagen levels in two separate mouse skin fibrosis models, one genetically based and the other chemically induced

SEA alters the TIMP production in trophoblast cells.

<p>The first-trimester cell line model, HTR8/SVneo, was treated with SEA (25 ug/ml) for 24 h. TIMP1 production is increased after SEA treatment. <i>P</i><0.02, n = 13 pairs of HTR8 cultured +/− SEA.</p

HTR8 cells increase pro-inflammatory cytokine production in response to plasma from schistosome-infected pregnant women.

<p>The first-trimester cell line, HTR8/SVneo, was cultured in serum-free media with the addition of 10% plasma from women with schistosomiasis or uninfected women at 32 weeks of gestation. Culture supernatants from cells with cultured with plasma from infected women had higher levels of A) IL-6, <i>P</i><0.02 and B) IL-8. <i>P</i><0.01. n = 58 (29/group). Median and IQR presented.</p

SEA inhibits trophoblast migration.

<p>HTR8/SVneo cells were grown to confluence before a linear scratch was made through the center of the growth area. Media was then replaced with either serum-free media alone, or serum-free media with SEA (25 µg/ml) for 48 h. Data for each well was analyzed as the percentage of the original denuded area remaining open at each time point. <b>A and B</b>) A well with media alone, at 0 h and 48 h. <b>C and D</b>) An area scratched and treated with SEA has little cell migration into the scratched region 48 h later. <b>E</b>) The percentage of area filled after 48 h in culture is significantly less in those wells exposed to SEA, <i>P</i><0.01, n = 5 pairs of HTR8 cells cultured +/− SEA.</p

Production of pro-inflammatory cytokines/chemokines are upregulated by SEA in HTR8 cells.

<p>The first-trimester cell line model, HTR8/SVneo, was treated with SEA (25 ug/ml) for 24 h. Media from all treatment conditions was collected and measured for cytokine expression. <b>A and B</b>) IL-6 & IL-8 production are both increased after SEA exposure. <i>P</i> = 0.01 and 0.02, respectively, n = 9 <b>C</b>) MCP1 production is increased after SEA treatment. <i>P</i><0.04, n = 13 pairs of HTR8 cells cultured +/− SEA.</p

Maternal, placental and cord blood cytokines and the risk of adverse birth outcomes among pregnant women infected with Schistosoma japonicum in the Philippines

Background The objectives of this study were to 1) evaluate the influence of treatment with praziquantel on the inflammatory milieu in maternal, placental, and cord blood, 2) assess the extent to which proinflammatory signatures in placental and cord blood impacts birth outcomes, and 3) evaluate the impact of other helminths on the inflammatory micro environment. Methods/Findings This was a secondary analysis of samples from 369 mother-infant pairs participating in a randomized controlled trial of praziquantel given at 12-16 weeks gestation. We performed regression analysis to address our study objectives. In maternal peripheral blood, the concentrations of CXCL8, and TNF receptor I and II decreased from 12 to 32 weeks gestation, while IL-13 increased. Praziquantel treatment did not significantly alter the trajectory of the concentration of any of the cytokines examined. Hookworm infection was associated with elevated placental IL-1, CXCL8 and IFN-gamma. The risk of small-for-gestational age increased with elevated IL-6, IL-10, and CXCL8 in cord blood. The risk of prematurity was increased when cord blood sTNFRI and placental IL-5 were elevated. Conclusions Our study suggests that fetal cytokines, which may be related to infectious disease exposures, contribute to poor intrauterine growth. Additionally, hookworm infection influences cytokine concentrations at the maternal-fetal interface. Clinical Trial Registry number and website ClinicalTrials.gov (NCT00486863). Author summary Schistosomiasis is one of the most prevalent parasitic tropical diseases, and it is primarily treated with the drug praziquantel. This study examined the effects of praziquantel treatment for schistosomiasis and the presence of geohelminth infections during pregnancy on cytokines in maternal, placental, and cord blood, and examined the effects of pro-inflammatory signatures at the maternal-fetal interface on perinatal outcomes. We analyzed the data of 369 mother-infant pairs obtained from a randomized controlled trial of praziquantel given at 12-16 weeks gestation. Praziquantel treatment did not significantly alter the trajectory of the concentration of any of the cytokines examined. Elevated levels of both Th1 and Th2 cytokines were associated with the risk of adverse perinatal outcomes (small-for-gestational age and prematurity). Hookworm coinfection at 12 weeks gestation was, however, related to elevated levels of certain cytokines in the placenta (IL-1, IL-5, CXCL8 and IFN-gamma).Funding Agencies|NIH/NIAID [U01AI066050, R21AI107520]</p

Antibody levels to recombinant VAR2CSA domains vary with Plasmodium falciparum parasitaemia, gestational age, and gravidity, but do not predict pregnancy outcomes

Abstract Background Maternal malaria is a tropical scourge associated with poor pregnancy outcomes. Women become resistant to Plasmodium falciparum pregnancy malaria as they acquire antibodies to the variant surface antigen VAR2CSA, a leading vaccine candidate. Because malaria infection may increase VAR2CSA antibody levels and thereby confound analyses of immune protection, gravidity-dependent changes in antibody levels during and after infection, and the effect of VAR2CSA antibodies on pregnancy outcomes were evaluated. Methods Pregnant women enrolled in a longitudinal cohort study of mother-infant pairs in Ouelessebougou, Mali provided plasma samples at enrollment, gestational week 30–32, and delivery. Antibody levels to VAR2CSA domains were measured using a multiplex bead-based assay. Results Antibody levels to VAR2CSA were higher in multigravidae than primigravidae. Malaria infection was associated with increased antibody levels to VAR2CSA domains. In primigravidae but not in secundigravidae or multigravidae, antibodies levels sharply declined after an infection. A relationship between any VAR2CSA antibody specificity and protection from adverse pregnancy outcomes was not detected. Conclusions During malaria infection, primigravidae acquire short-lived antibodies. The lack of an association between VAR2CSA domain antibody reactivity and improved pregnancy outcomes suggests that the recombinant proteins may not present native epitopes targeted by protective antibodies

Immunoglobulin E (IgE) Responses to Paramyosin Predict Resistance to Reinfection with Schistosoma japonicum and Are Attenuated by IgG4▿

Schistosomiasis remains a public health concern in developing countries, and rapid reinfection fostered by continued exposure to contaminated water sources necessitates a vaccine to augment current mass treatment-based control strategies. We report isotype-specific (immunoglobulin A [IgA], IgE, IgG1, IgG4, and IgG) antibody responses to soluble worm antigen preparation and the recombinant vaccine candidates rSj97, rSj67, and rSj22 from a Schistosoma japonicum-infected cohort in Leyte, the Philippines, where schistosomiasis is endemic. Sera were collected from infected individuals 1 month posttreatment with praziquantel, and antibody responses were measured using a bead-based multiplex platform. Reinfection was monitored by stool sampling every 3 months, and data up to 1 year were included in the analysis (n = 553). In repeated-measures models, individuals with detectible IgE responses to rSj97 had a 26% lower intensity of reinfection at 12 months posttreatment compared to nonresponders after adjusting for age, gender, village, exposure, pretreatment infection intensity, and clustering by household (P = 0.018). In contrast, IgG4 responses to rSj97 as well as rSj67 and rSj22 were associated with markedly increased reinfection intensity. When stratified by IgG4 and IgE responder status, individuals with IgE but not IgG4 responses to rSj97 (n = 16) had a 77% lower intensity of reinfection at 12 months compared to individuals with IgG4 responses but not IgE responses (n = 274), even after adjusting for potential confounders (P = 0.016). Together with our previously described protective cytokine responses, these data further support paramyosin as a leading vaccine candidate for human schistosomiasis japonica and underscore the importance of careful adjuvant selection to avoid the generation of blocking IgG4 antibody responses