Gravidity modifies the associations of age and spousal age difference with couple's fecundability: a large cohort study from China.

STUDY QUESTION: Do couple's age ranges for optimal fecundability, and the associations with fecundability of couple's age combinations and age differences differ with gravidity? SUMMARY ANSWER: The couple's age range of optimal fecundability and age combinations differed with gravidity, and gravidity might modify the associations of age and spousal age difference with couple's fecundability. WHAT IS KNOWN ALREADY: Age is one of the strongest determinants of fecundability, but the existing studies have certain limitations in study population, couple's extreme age combinations and age differences, and have not explored whether the association between age and fecundability differs with gravidity. STUDY DESIGN, SIZE, DURATION: Retrospective cohort study. 5 407 499 general reproductive-aged couples (not diagnosed with infertility) participated in the National Free Pre-conception Check-up Projects during 2015-2017. They were followed up for pregnancy outcomes through telephone interviews every 3 months until they became pregnant or were followed up for 1 year. PARTICIPANTS/MATERIALS, SETTING, METHODS: The main outcome was time to pregnancy, and the fecundability odds ratios and 95% CIs were estimated using the Cox models for discrete survival time. The associations of age and spousal age difference with fecundability were evaluated by restricted cubic splines. MAIN RESULTS AND THE ROLE OF CHANCE: In this large cohort of general reproductive-aged population, the age of optimal fecundability of multigravida couples was older than that of nulligravida couples, but their subsequent fecundability declined more sharply with age. The decline in female fecundability was more pronounced with age, with fecundability dropping by ∼30% in both nulligravida and multigravida couples whose female partners aged ≥35 years. In the nulligravida group, the fecundability of couples who were both ≤24 years with the same age was the highest, which decreased steadily with the increase of spousal age difference, and younger male partners did not seem to contribute to improving couple's fecundability. In the multigravida group, couples with female partners aged 25-34 years and a spousal age difference of -5 to 5 years showed higher fecundability, and the effect of spousal age difference on couple's fecundability became suddenly apparent when female partners aged around 40 years. Young male partners were unable to change the decisive effect of female partner's age over 40 years on couple's reduced fecundability, regardless of gravidity. LIMITATIONS, REASONS FOR CAUTION: Lacking the time for couples to attempt pregnancy before enrollment, and some couples might suspend pregnancy plans during follow-up because of certain emergencies, which would misestimate the fecundability. Due to the lack of information on sperm quality and sexual frequency of couples, we could not adjust for these factors. Moreover, due to population characteristics, the extrapolation of our results required caution. WIDER IMPLICATIONS OF THE FINDINGS: The couple's age range of optimal fecundability, age combinations, and spousal age difference on fecundability varied with gravidity. Female age-related decline in fecundability was more dominant in couple's fecundability. Targeted fertility guidance should be provided to couples with different age combinations and gravidities. STUDY FUNDING/COMPETING INTEREST(S): This research received funding from the Project of National Research Institute for Family Planning (Grant No. 2018NRIFPJ03), the National Key Research and Development Program of China (Grant No. 2016YFC1000307), and the National Human Genetic Resources Sharing Service Platform (Grant No. 2005DKA21300), People's Republic of China. The funders had no role in study design, analysis, decision to publish, or preparation of the manuscript. The authors report no conflict of interest. TRIAL REGISTRATION NUMBER: N/A.

Association of Fine Particulate Matter and Its Components with Macrosomia: A Nationwide Birth Cohort Study of 336 Chinese Cities.

To examine the associations between macrosomia risk and exposure to fine particulate matter (PM2.5) and its chemical components during pregnancy, we collected birth records between 2010 and 2015 in mainland China from the National Free Preconception Health Examination Project and used satellite-based models to estimate concentrations of PM2.5 mass and five main components, namely, black carbon (BC), organic carbon (OC), nitrate (NO3-), sulfate (SO42-), and ammonium (NH4+). Associations between macrosomia risk and prenatal exposure to PM2.5 were examined by logistic regression analysis, and the sensitive subgroups were explored by stratified analyses. Of the 3,248,263 singleton newborns from 336 cities, 165,119 (5.1%) had macrosomia. Each interquartile range increase in concentration of PM2.5 during the entire pregnancy was associated with increased risk of macrosomia (odds ratio (OR) = 1.18; 95% confidence interval (CI), 1.17-1.20). Among specific components, the largest effect estimates were found on NO3- (OR = 1.36; 95% CI, 1.35-1.38) followed by OC (OR = 1.23; 95% CI, 1.22-1.24), NH4+ (OR = 1.22; 95% CI, 1.21-1.23), and BC (OR = 1.21; 95% CI, 1.20-1.22). We also that found boys, women with a normal or lower prepregnancy body mass index, and women with irregular or no folic acid supplementation experienced higher risk of macrosomia associated with PM2.5 exposure.

Evaluating the Impact of Maternal Exposure to Ozone on Twin Fetal Growth in China.

Unlike singletons, twins require attention not only to the birth weight of the fetuses but also to discordance (i.e., the differences between weights) because twin growth discordance is a significant factor contributing to perinatal mortality and morbidity in twin pregnancies. However, the impact of maternal air pollution exposure on twin growth discordance has rarely been investigated. We examined the association of long-term ozone exposure during preconception and pregnancy with the birth weight of twins and twin growth discordance among 35,795 twins from the National Free Preconception Health Examination Project between January 2010 and December 2019. Linear mixed-effect models and random-effect logistic regression models were used to examine the associations of ozone exposure with the birth weight-related outcomes (i.e., birth weight of twins and within-pair birth weight difference) and risk of twin growth discordance, respectively, after adjustment for demographic characteristics and lifestyle. We found that an interquartile range (IQR) increase (15 µg/m3) in ozone exposure during the entire pregnancy was associated with a reduction (-28.96g, 95% confidence interval [CI]: -46.37, -11.56) in the total birth weight of twins, and ozone had a more pronounced impact on the birth weight of the smaller fetuses (-18.28 g, 95% CI: -27.22, -9.34) compared to the larger fetuses (-9.88 g, 95% CI: -18.84, -0.92) in twin pregnancies. An IQR increase in ozone exposure during the entire pregnancy was associated with a significant increase (8.41 g, 95% CI: 4.13, 12.69) in the within-pair birth weight difference; the odds ratio (OR) of twin growth discordance related to ozone exposure increased by 9% (OR = 1.09, 95% CI: 1.01, 1.18). However, no consistently significant associations were observed for ozone exposure during prepregnancy. Male-male twin pairs and those who were born prematurely appeared to be more susceptible to ozone exposure than their counterparts. Long-term ozone exposure during pregnancy was associated with twin growth discordance, and our findings provide reference data for future studies.

The type of previous abortion modifies the association between air pollution and the risk of preterm birth.

BACKGROUND: Air pollution and previous abortion have been reported to be related to preterm birth (PTB). But rare study examined the effect of air pollution on PTB risk among mothers with previous abortion. OBJECTIVE: To estimate the effect of air pollution on PTB and the potential effect modification of previous abortion on such an association in rural part of Henan province (China). METHOD: Based on National Free Preconception Health Examination Project (NFPHEP), information from the medical records of 57,337 mothers with previous abortion were obtained. An inverse distance-weighted model was used to estimate exposure levels of air pollutants. The effect of air pollution on the risk of PTB was estimated with a multiple logistic regression model. Stratified and interaction analyses were undertaken to explore the potential effect modification of previous abortion on this association. RESULTS: The risk of PTB was positively associated with exposure to levels of nitrogen dioxide (NO2; OR: 1.03; 95%CI: 1.02-1.04)], and sulfur dioxide (SO2; 1.04; 1.02-1.07), and negatively associated with ozone (O3) exposure (0.97; 0.97-0.98) during the entire pregnancy. Besides, we observed a positive effect of carbon monoxide (CO) exposure during the third trimester of pregnancy on PTB (1.14; 1.01-1.29). The type of previous abortion could modify the effect of air pollution on the PTB risk (P-interaction < 0.05). Compared with mothers with previous induced abortion, mothers with previous spontaneous abortion carried a higher risk of PTB induced by NO2, CO, and O3. CONCLUSIONS: The risk of PTB was positively associated with levels of NO2, SO2 and CO, and negatively associated with the O3 level. The types of previous abortion could modify the effect of air pollution on PTB. Mothers who had an abortion previously, especially spontaneous abortion, should avoid exposure to air pollution to improve their pregnancy outcome.

Associations of MCM8 rs3761873 and rs16991617 variants with abnormal uterine bleeding induced by copper intrauterine device.

AIM: Intrauterine device (IUD) is a commonly used contraceptive method worldwide. Abnormal uterine bleeding (AUB) is one of the most common side effects of Cu-IUDs. Since AUB varies among Cu-IUD users, changes in the bleeding-related genetic factors may contribute to AUB. This study aimed to determine the genetic risk factors of AUB after Cu-IUD insertion. METHODS: We conducted a case-control study on women who experienced AUB after Cu-IUD insertion (case:control = 62:59). Six candidate variants were genotyped using the Sequenom MassARRAY. Genotype and allele frequencies were analyzed using SHEsisPlus. We performed Pearson's Chi-squared test to analyze categorical data, and ESEfinder to predict the impact on splicing regulation. RESULTS: MCM8 coding sequence variants: rs3761873-A>C was in Exon 7 and rs16991617 A>G was in Exon 12 of all 19 exons, both of which were significantly different between cases and controls (pallele  = 0.039 and pgenotype  = 0.092). rs6022 and rs6029 in F5 gene and rs3761873 and rs16991617 in the MCM8 gene showed strong linkage disequilibrium (R2 > 0.8). ESEfinder indicated that the variants of MCM8 may affect the splicing regulation. CONCLUSIONS: MCM8 rs376187 and rs16991617 were associated with AUB in Cu-IUDs users. MCM8 may play a role in AUB by regulating functions of reproductive organs and primary ovarian insufficiency. Our findings may improve the understanding of the genetic basis of AUB caused by Cu-IUDs.

Influence of margin design and restorative material on the stress distribution of endocrowns: a 3D finite element analysis.

BACKGROUND: This study aimed to evaluate the stress distributions in endocrown restorations as applied to endodontically treated teeth (ETT), according to the factors of "margin design" (four levels) and "restorative material" (six levels). METHODS: Four 3D-finite elements models were constructed for endocrown restored molars considering different margin designs. Model A was prepared with a flat butt joint margin and received an endocrown with a 2.0-mm occlusal thickness. Model B was prepared with a 20° bevel margin and received an endocrown with a 2.0-mm occlusal thickness. Model C was prepared with an axial reduction and 1-mm shoulder margin and received an endocrown with a 2.0-mm occlusal thickness. Model D was prepared with an anatomic margin and received an endocrown with a 2.0-mm occlusal thickness. The following endocrown materials were used: In-Ceram Zirconia (Zr), Vita Suprinity (VS), IPS Empress (IE), Grandio blocs (GR), VisCalor bulk (VS), and CopraPeek Light (CP). The Load application (600 N) was performed at the food bolus and tooth surface during the closing phase of the chewing cycle. The results for the endocrown and tooth remnants were determined according to the von Mises stress. The failure risk of the cement layer was also calculated based on the normal stress criterion. RESULTS: Model D (with an anatomic margin) showed the greatest stress concentrations, especially in the irregular and sharp angles of the restoration and tooth remnants. The stress concentrated on the dentin was significantly lower in Model B with a 20° bevel margin (20.86 MPa), i.e., 1.3 times lower than the other three margin designs (27.80 MPa). Restorative materials with higher elastic moduli present higher stress concentrations inside the endocrown and transmit less stress to the cement layer, resulting in lower bonding failure risks. In contrast, materials with an elastic modulus similar to that of dentin presented with a more homogeneous stress distribution on the whole structure. CONCLUSIONS: An endocrown with a 20° bevel margin design could be a favorable preparation option for ETT. Composite resins (GR and VC) exhibit a more even stress distribution, and seem to be more promising materials for endocrown molars.

Optimal cuspal coverage of ceramic restorations using CAD/CAM: Biomechanical characteristic analysis by 3D finite element analysis and in vitro investigation.

AIM: The present in vitro study aimed to evaluate the stress distribution patterns, resistance to fracture, and failure modes of endodontically treated molars restored with different cuspal coverage options. MATERIALS AND METHODS: Three-dimensional models of mandibular first molars with six kinds of typical cuspal coverage were generated: T1: mesiobuccal cuspal coverage; T2: coverage of all buccal cusps; T3: mesiolingual cuspal coverage; T4: coverage of all lingual cusps; T5: mesiobuccal and mesiolingual cuspal coverage; T6: coverage of all cusps. All restorations were fabricated with zirconia-reinforced lithium silicate ceramic. The stress and its distributions under axial and oblique loading were analyzed by finite element analysis (FEA). Sixty human mandibular molar samples were randomly allocated into six groups (n = 10) to simulate the application of six types of restorations with different cuspal coverage, as in the FEA analysis, and were then subjected to a compressive test. All fractured specimens were subjected to fractography. Data were analyzed by one-way analysis of variance (ANOVA), the Tukey post hoc test, and the Fisher exact test (α = 0.05). RESULTS: The T2 and T6 groups presented superior stress distribution patterns under both axial and oblique loading compared with the other models. The fracture loads in the T2 (1627 ± 358 N) and T6 (1639 ± 355 N) groups were significantly higher than those in the other groups (P < 0.05). The T2 and T6 groups exhibited more restorable failure modes. Fractography showed more cracks below the cementoenamel junction in the T3, T4, and T5 groups. CONCLUSIONS: Onlay restorations with whole functional cuspal coverage provided comparable effects to coverage of all cusps in endodontically treated molars, and both methods exhibited a more even stress distribution and fracture resistance and better mechanical performance in high occlusal areas than other types of cuspal coverage. (Int J Comput Dent 2022;25(3):267-276; doi: 10.3290/j.ijcd.b2599709).

Antibody-dependent enhancement (ADE) of dengue virus: Identification of the key amino acid that is vital in DENV vaccine research.

BACKGROUND: The antibody-dependent enhancement (ADE) of dengue virus (DENV) has critically restricted vaccine development. Prior research suggested pr4 as the probable ADE epitope of DENV. METHODS: Chimeric DENV was constructed by replacing the DENV pr4 gene with the corresponding Japanese encephalitis virus (JEV) gene to determine whether it can reduce ADE activities. An alanine scanning method and bioinformatics analysis were utilized to identify the amino acid of pr4 that was crucial as an ADE epitope. RESULTS: Chimeric virus reduced ADE and virulence. The amino acids at the following locations on the mutant peptides showed significantly reduced binding ability to prM antibody: pr4.5 (position 5 - leucine), pr4.6 (position 6 - leucine), pr4.7 (position 7 - phenyalanine) and pr4.16 (position 16 - cysteine). The four amino acids had formed a pocket-like structure, which could increase the possibility of binding to an antibody. CONCLUSIONS: ADE activities could be reduced by replacing the DENV pr4 gene with the corresponding JEV gene. Leucine at position 5, leucine at position 6, phenyalanine at position 7 and cysteine at position 16 were the key amino acid sites in the ADE response of DENV. The occurrence of ADE can potentially be reduced by the replacement of key amino acids, hence highlighting its possible contribution to dengue vaccine design, paving a way for future vaccine research.

Effects of ambient temperature on the risk of preterm birth in offspring of adolescent mothers in rural henan, China.

BACKGROUND: A number of studies have explored the association between ambient temperature and preterm birth (PTB), but rarely among adolescent mothers. OBJECTIVES: To estimate the effects of ambient temperature on the risk of PTB and gestational age of newborns delivered by adolescent mothers in rural areas of Henan province. METHODS: We obtained 5394 medical records of adolescent mothers with results of pre-pregnancy physical examination and pregnancy outcomes from the National Free Preconception Health Examination Project (NFPHEP) in Henan province. Meteorological information was obtained from the China Meteorological Data Sharing Service System. Individual exposure levels were evaluated with an inverse distance-weighted model. A multiple logistic regression model and multiple linear regression model were used to estimate the effects of ambient temperature on the risk of PTB and gestational age, respectively. Stratified and interaction analyses were also performed. RESULTS: Of newborns in this study, 3.45% (186/5394) were PTB. Mean, maximum and minimum temperature during the entire pregnancy, especially the last 1-4 weeks of pregnancy, were positively associated with the risk of PTB and negatively associated with gestational age (P < 0.05). Nevertheless, a masking effect was observed that gestational age was positively associated with ambient temperature during the first trimester of pregnancy, due to the strongly inverse correlation between ambient temperature during the early and late stages of pregnancy. Stratified analyses showed that increasing temperature during the last 1-4 weeks of pregnancy increased the risk of PTB and decreased gestational age in newborns born in the cold season (P < 0.05). Furthermore, interaction analyses showed that birth season modified the effects of temperature on the gestational age (Pinteraction < 0.10). CONCLUSIONS: Elevated ambient temperature can decrease gestational age and increase the risk of PTB in offspring of adolescent mothers in rural areas. The birth season may modify the effects of temperature on gestational age.

The role of maternal methylation in the association between prenatal meteorological conditions and neonatal H19/H19-DMR methylation.

Meteorological conditions during pregnancy can affect birth outcome, which has been linked to the H19/H19-differentially methylated region (DMR). However, the detailed mechanisms underlying this association are unclear. This was investigated in the present study to provide epidemiological evidence for elucidating the pathogenesis of adverse birth outcomes. A total of 550 mother-newborn pairs were recruited in Zhengzhou, China from January 2010 to January 2012. Meteorological data including temperature (T), relative humidity (RH), and sunshine duration (SSD) were obtained from the China Meteorological Data Sharing Service System. Bisulfite sequencing PCR was performed to determine the methylation levels of H19/H19-DMR using genomic DNA extracted from maternal peripheral and umbilical cord blood. The results showed that H19-DMR methylation status in cord blood was positively associated with that in maternal blood. Neonatal H19-DMR methylation was negatively associated with T and RH during the first trimester and positively associated with these variables during the third trimester. There was a positive correlation between neonatal H19-DMR methylation and SSD during the second trimester and a negative correlation during the third trimester. Similar associations were observed between maternal H19-DMR methylation and prenatal meteorological conditions. We also observed significant interaction effects of maternal H19/H19-DMR methylation and most prenatal meteorological factors on neonatal methylation, and found that changes in the methylation status of maternal H19-DMR were responsible for the effects of prenatal meteorological conditions on neonatal methylation. In summary, neonatal H19-DMR methylation was significantly associated with prenatal meteorological conditions, which was modified and mediated by maternal H19-DMR methylation changes. These findings provide insights into the relationship between meteorological factors during pregnancy and adverse birth outcomes or disease susceptibility in offspring, and can serve as a reference for environmental policy-making.

[Association between vitamin D deficiency and Toxoplasma gondii infection in women of childbearing age].

OBJECTIVE: To explore the association between the risk of vitamin D deficiency and the infection of Toxoplasma gondii in women of childbearing age. METHODS: Based on a Women's Reproductive Health Cohort Study performed from 2007 to 2010 in four counties of Henan Province, Toxoplasma gondii infection were tested by enzyme linked immunosorbent assay(ELISA). A total of 1151 women with pregnancy outcomes were followed up and pre-pregnancy vitamin D level was measured with serum samples. Case-control study was used to examine the association between the risk of vitamin D deficiency and Toxoplasma infection. RESULTS: The prevalence of vitamin D deficiency was 61. 5%(95% CI 59. 2%-64. 9%) and Toxoplasma infection was 9. 6%(95% CI 7. 9%-11. 4%), among which IgG positive, IgM positive and both positive were 7. 6%, 2. 3% and 0. 3%, respectively. After adjusting confounding factors, including education, family annual income, and dietary intake frequencies. , it was found that the risk of vitamin D deficiency in women infected with Toxoplasma gondii recently or previously was 1. 75 times higher than that of uninfected women(95% CI 1. 11-2. 77). CONCLUSION: There is association between the risk of vitamin D deficiency and the infection of Toxoplasma gondii in women of childbearing age.

Avian Influenza A (H7N9) viruses isolated from patients with mild and fatal infection differ in pathogenicity and induction of cytokines.

Since 2013, a novel Influenza A (H7N9) virus strain has continued to circulate within poultry and causing human disease. Influenza A (H7N9) virus results in two types of infection: mild and severe. The different results of clinical findings may be related with host susceptibility and characteristics of the virus itself. In order to investigate potential pathogenesis of Influenza A (H7N9) virus, we performed pathogenecity and cytokines analysis of two isolates, A/Guangdong/6/2013 H7N9 virus (GD-6) from a patient with a mild infection, and A/Guangdong/7/2013 H7N9 virus (GD-7) from a patient with a fatal infection. We found that GD-7 replicated to higher levels than GD-6 in human peripheral blood mononuclear cells (PBMCs), lung tissues, and mice. Furthermore, GD-7 infection resulted in more severe lung damage in mice lung tissues than GD-6 infection. GD-7 elicited higher levels of interleukin-6 (IL-6) and tumor necrosis factor-α(TNF-α) than GD-6 did. In conclusion, GD-7 was more pathogenic and induced higher levels of proinflammatory cytokines than GD-6 did.

Comprehensive mapping infection-enhancing epitopes of dengue pr protein using polyclonal antibody against prM.

Dengue vaccine development is considered a global public health priority, but the antibody-dependent enhancement (ADE) issues have critically restricted vaccine development. Recent findings have demonstrated that pre-membrane (prM) protein was involved in dengue virus (DENV) infection enhancement. Although the importance of prM antibodies have been well characterized, only a few epitopes in DENV prM protein have ever been identified. In this study, we screened five potential linear epitopes located at positions pr1 (1-16aa), pr3 (13-28aa), pr4 (19-34aa), pr9 (49-64aa), and pr10 (55-70aa) in pr protein using peptide scanning and comprehensive bioinformatics analysis. Then, we found that only pr4 (19-34aa) could elicit high-titer antibodies in Balb/c mice, and this epitope could react with sera from DENV2-infected patients, suggesting that specific antibodies against epitope peptide pr4 were elicited in both DENV-infected mice and human. In addition, our data demonstrated that anti-pr4 sera showed limited neutralizing activity but significant ADE activity toward standard DENV serotypes and imDENV. Hence, it seems responsible to hypothesize that anti-pr4 serum was infection-enhancing antibody and pr4 was infection-enhancing epitope. In conclusion, we characterized a novel infection-enhancing epitope on dengue pr protein, a finding that may provide new insight into the pathogenesis of DENV infection and contribute to dengue vaccine design.

Replacement of pr gene with Japanese encephalitis virus pr using reverse genetics reduces antibody-dependent enhancement of dengue virus 2 infection.

Severe dengue is more likely found during secondary heterologous dengue virus (DENV) infection or primary infection of infants born to dengue-immune mothers and led to the hypothesis of antibody-dependent enhancement (ADE). It has been reported that pre-membrane (prM)-reactive antibodies do not efficiently neutralize DENV infection but instead potently promote ADE infection. Meanwhile, these enhancing anti-prM antibodies mainly react with the precursor (pr) peptide. To evaluate the effect of pr gene substitution on neutralization and ADE of DENV infection, a novel chimeric dengue virus (JEVpr/DENV2) was rationally constructed by replacing the DENV pr gene with Japanese encephalitis virus (JEV) pr gene, based on the full-length infectious complementary DNA (cDNA) clone of DENV2 ZS01/01. We found that chimeric JEVpr/DENV2 showed reduced virulence and good immunogenicity. In addition, anti-JEVpr/DENV2 sera showed broad cross-reactivity and efficient neutralizing activity with all four DENV serotypes and immature DENV2 (ImDENV2). Most importantly, compared with anti-DENV2 sera, anti-JEVpr/DENV2 sera showed significantly reduced enhancing activity of DENV infection in K562 cells. These results suggest that the ADE activities could be reduced by replacing the DENV pr gene with JEV pr gene. These findings may help us better understand the pathogenesis of DENV infection and provide a reference for the development of a vaccine against DENV.

Tim-3-expressing CD4+ and CD8+ T cells in human tuberculosis (TB) exhibit polarized effector memory phenotypes and stronger anti-TB effector functions.

T-cell immune responses modulated by T-cell immunoglobulin and mucin domain-containing molecule 3 (Tim-3) during Mycobacterium tuberculosis (Mtb) infection in humans remain poorly understood. Here, we found that active TB patients exhibited increases in numbers of Tim-3-expressing CD4(+) and CD8(+) T cells, which preferentially displayed polarized effector memory phenotypes. Consistent with effector phenotypes, Tim-3(+)CD4(+) and Tim-3(+)CD8(+) T-cell subsets showed greater effector functions for producing Th1/Th22 cytokines and CTL effector molecules than Tim-3(-) counterparts, and Tim-3-expressing T cells more apparently limited intracellular Mtb replication in macrophages. The increased effector functions for Tim-3-expressing T cells consisted with cellular activation signaling as Tim-3(+)CD4(+) and Tim-3(+)CD8(+) T-cell subsets expressed much higher levels of phosphorylated signaling molecules p38, stat3, stat5, and Erk1/2 than Tim-3- controls. Mechanistic experiments showed that siRNA silencing of Tim-3 or soluble Tim-3 treatment interfering with membrane Tim-3-ligand interaction reduced de novo production of IFN-γ and TNF-α by Tim-3-expressing T cells. Furthermore, stimulation of Tim-3 signaling pathways by antibody cross-linking of membrane Tim-3 augmented effector function of IFN-γ production by CD4(+) and CD8(+) T cells, suggesting that Tim-3 signaling helped to drive stronger effector functions in active TB patients. This study therefore uncovered a previously unknown mechanism for T-cell immune responses regulated by Tim-3, and findings may have implications for potential immune intervention in TB.

Relatively low level of antigen-specific monocytes detected in blood from untreated tuberculosis patients using CD4+ T-cell receptor tetramers.

The in vivo kinetics of antigen-presenting cells (APCs) in patients with advanced and convalescent tuberculosis (TB) is not well characterized. In order to target Mycobacterium tuberculosis (MTB) peptides- and HLA-DR-holding monocytes and macrophages, 2 MTB peptide-specific CD4(+) T-cell receptor (TCR) tetramers eu and hu were successfully constructed. Peripheral blood (PBL) samples from inpatients with advanced pulmonary TB (PTB) were analyzed using flow cytometry, and the percentages of tetramer-bound CD14(+) monocytes ranged from 0.26-1.44% and 0.21-0.95%, respectively; significantly higher than those measured in PBL samples obtained from non-TB patients, healthy donors, and umbilical cords. These tetramers were also able to specifically detect macrophages in situ via immunofluorescent staining. The results of the continuous time-point tracking of the tetramer-positive rates in PBL samples from active PTB outpatients undergoing treatment show that the median percentages were at first low before treatment, increased to their highest levels during the first month, and then began to decrease during the second month until finally reaching and maintaining a relatively low level after 3-6 months. These results suggest that there is a relatively low level of MTB-specific monocytes in advanced and untreated patients. Further experiments show that MTB induces apoptosis in CD14(+) cells, and the percentage of apoptotic monocytes dramatically decreases after treatment. Therefore, the relatively low level of MTB-specific monocytes is probably related to the apoptosis or necrosis of APCs due to live bacteria and their growth. The bactericidal effects of anti-TB drugs, as well as other unknown factors, would induce a peak value during the first month of treatment, and a relatively low level would be subsequently reached and maintained until all of the involved factors reached equilibrium. These tetramers have diagnostic potential and can provide valuable insights into the mechanisms of antigen presentation and its relationship with TB infection and latent TB infection.

Tetravalent recombinant dengue virus-like particles as potential vaccine candidates: immunological properties.

BACKGROUND: Currently, a licensed vaccine for Dengue Virus (DENV) is not yet available. Virus-like particles (VLP) have shown considerable promise for use as vaccines and have many advantages compared to many other types of viral vaccines. VLPs have been found to have high immunogenic potencies, providing protection against various pathogens. RESULTS: In the current study, four DENV-VLP serotypes were successfully expressed in Pichia pastoris, based on co-expression of the prM and E proteins. The effects of a tetravalent VLP vaccine were also examined. Immunization with purified, recombinant, tetravalent DENV1-4 VLPs induced specific antibodies against all DENV1-4 antigens in mice. The antibody titers were higher after immunization with the tetravalent VLP vaccine compared to titers after immunization with any of the dengue serotype VLPs alone. Indirect immunofluorescence assay (IFA) results indicated that sera from VLP immunized mice recognized the native viral antigens. TNF-α and IL-10 were significantly higher in mice immunized with tetravalent DENV-VLP compared to those mice received PBS. The tetravalent VLP appeared to stimulate neutralizing antibodies against each viral serotype, as shown by PRNT50 analysis (1:32 against DENV1 and 2, and 1:16 against DENV3 and 4). The highest titers with the tetravalent VLP vaccine were still a little lower than the monovalent VLP against the corresponding serotype. The protection rates of tetravalent DENV-VLP immune sera against challenges with DENV1 to 4 serotypes in suckling mice were 77, 92, 100, and 100%, respectively, indicating greater protective efficacy compared with monovalent immune sera. CONCLUSIONS: Our results provide an important basis for the development of the dengue VLP as a promising non-infectious candidate vaccine for dengue infection.

Rhamnolipids elicit the same cytotoxic sensitivity between cancer cell and normal cell by reducing surface tension of culture medium.

Biosurfactant rhamnolipids have been claimed to show biological activities of inhibiting the proliferation of cancer cells. In this study, the cytotoxicity of rhamnolipids was examined on four cancer cells (HepG2, Caco-2, Hela, MCF-7 cells) and two normal cells (HK-2 cell, primary hepatocyte). Interestingly, both cancer cells and normal cells exhibited similar sensitivities to the addition of rhamnolipids in culture medium, and the cytotoxicity was largely attenuated by the presence of fetal bovine serum (FBS) in culture medium. In correlation of the mono-/di-rhamnolipid cytotoxicity with the surface tension of culture medium, it was found that rhamnolipids triggered cytotoxicity whenever the surface tension of culture medium decreased below 41 mN/m irrespective of the FBS content in culture medium, cell line, or rhamnolipid congener. Similarly, each chemical surfactant (Tween-80, sodium dodecyl sulfate, and sodium dodecyl benzene sulfonate) could cause cytotoxicity on HepG2 cells whenever its addition made the surface tension under 41 mN/m in culture medium with or without the presence of FBS. It seems that rhamnolipids, like chemical surfactants, exhibited cytotoxicity by reducing the surface tension of culture medium rather than by changing its specific molecular structure, which had no selection on tumor cells. This study could offer helps to correct the misleading biological activity of rhamnolipids and to avoid the possible large wastes of time and expenses on developing the applications in antitumor drugs.

Association between fine particulate matter and fecundability in Henan, China: A prospective cohort study.

OBJECTIVE: To investigate the relationship between ambient fine particulate matter (PM2.5) exposure and fecundability. METHODS: This study included 751,270 female residents from Henan Province who participated in the National Free Pre-conception Check-up Projects during 2015-2017. Ambient cycle-specific PM2.5 exposure was assessed at the county level for each participant using satellite-based PM2.5 concentration data at 1-km resolution. Cox proportional hazards models with time-varying exposure were used to estimate the association between fecundability and PM2.5 exposure, adjusted for potential individual risk factors. RESULTS: During the study period, 568,713 participants were pregnant, monthly mean PM2.5 concentrations varied from 25.5 to 114.0 µg/m3 across study areas. For each 10 µg/m3 increase in cycle-specific PM2.5, the hazard ratio for fecundability was 0.951 (95 % confidence interval: 0.950-0.953). The association was more pronounced in women who were older, with urban household registration, history of pregnancy, higher body mass index (BMI), hypertension, without exposure to tobacco, or whose male partners were older, with higher BMI, or hypertension. CONCLUSION: In this population-based prospective cohort, ambient cycle-specific PM2.5 exposure was associated with reduced fecundability. These findings may support the adverse implications of severe air pollution on reproductive health.

Preconception mitochondrial DNA copy number plays a crucial role in linking prenatal air pollution with the risk of preterm birth.

The relationship between maternal peripheral blood mitochondrial DNA and adverse pregnancy outcomes, specifically preterm birth (PTB), remains uncertain. To investigate the effects of preconception mitochondrial DNA copy number (mtDNAcn) on the association between prenatal air pollutants exposure and PTB risk, a total of 1871 expectant mothers from six regions in Henan Province were recruited. Information regarding air pollutants was obtained from 151 environmental monitoring sites, and relative mtDNAcn was evaluated using real-time PCR analysis. After adjusting for potential confounding variables, it was determined that the risk of PTB increased with elevated levels of inhalable particulate matter (PM10), fine particulate matter (PM2.5), sulfur dioxide (SO2), carbon monoxide (CO) and ozone (O3) exposure (P < 0.05) but decreased with higher nitrogen dioxide (NO2) exposure (0.05 < P < 0.10) during the entire pregnancy. Additionally, the preconception relative mtDNAcn was lower in the PTB group (0.82 ± 0.23) compared to the term group (0.92 ± 0.29). Furthermore, for each 0.1-unit increase in preconception mtDNAcn, the risk of PTB decreased by 14.8%. Stratified analyses revealed that the risk of PTB rose with increasing O3 concentrations, regardless of the relative mtDNAcn. Moreover, the study found a significant association between PTB risk and prenatal exposure to elevated PM10, PM2.5, SO2, and CO, particularly in mothers with low mtDNAcn (≤0.88) (P < 0.05). Conversely, a decrease in the PTB risk was observed with elevated NO2 exposure in mothers with high mtDNAcn (>0.88). Interaction analysis revealed that exposure to PM10, PM2.5, SO2, NO2, and CO interacted with mtDNAcn, respectively, affecting PTB risk (P-interaction<0.05). These findings indicate a noteworthy association between PTB risk and prenatal air pollutants exposure, which is influenced by the preconception mtDNAcn.