Reduction in transplacental transmission of Neospora caninum in outbred mice by vaccination

Infection with the protozoan parasite Neospora caninum is an important cause of abortion in cattle. A major source of infection is transplacental transfer of the parasite from mother to offspring during pregnancy. This study describes investigations on the immunisation of outbred Qs mice before pregnancy with live or a crude lysate of N. caninum (NC-Nowra isolate) to prevent transplacental transfer of a challenge infection administered during pregnancy. Parasites present in the brains of pups from mice challenged with N. caninum (NC-Liverpool) were detected by PCR. Injection of live NC-Nowra tachyzoites before pregnancy dramatically reduced transplacental transfer from 75 to 0.8% in one experiment and from 76 to 8% in a second experiment. Injection of a crude lysate of NC-Nowra tachyzoites reduced transplacental transfer from 67 to 53% in one experiment and from 76 to 63% in a second experiment. Analysis of N. caninum-specific IgG1 and IgG2a antibody levels prior to pregnancy and challenge showed that NC-Nowra lysate induced a response skewed towards IgG1 whereas live parasites induced both IgG1 and IgG2a antibodies. After pregnancy and a challenge infection, a similar IgG1/IgG2a response was seen in all challenged groups. These results provide further positive support for the hypothesis that transplacental transmission of this parasite is preventable by vaccination.     

Is IgG galactosylation the relevant factor for pregnancy-induced remission of rheumatoid arthritis?

During pregnancy, most patients with rheumatoid arthritis (RA) experience spontaneous improvement of their disease activity. Among the soluble candidates that have been investigated in search for the most relevant disease-remitting factor are the galactosylation levels of immunoglobulin G (IgG). In RA, a higher percentage of IgG lacking the terminal galactose residues, thought to play a pro-inflammatory role, is found. During pregnancy, however, IgG galactosylation levels increase and correlate with improved disease activity. The question remains whether the increase in IgG galactosylation during pregnancy is a mere epiphenomenon or a true remission-inducing factor.     

Diagnosis of toxoplasmosis in pregnancy: importance of immunoglobulin G avidity test

The immunoglobulin G (IgG) avidity test has proved to be a highly useful test in the diagnosis of toxoplasmosis during pregnancy, especially in combination with conventional serological assays. Acute infections at the time of gestation predispose the offspring to the risk of congenital toxoplasmosis. The IgG avidity test was developed to differentiate between recent and more distant infection; this method is valuable in the situation in which a single serum sample is obtained in the first trimester of pregnancy. This paper describes the utility of IgG avidity test during pregnancy, and its role in ruling out, by a high avidity, a recently acquired infection. Testing for specific IgG avidity has been reported to be useful for confirmatory testing in patients who have positive IgG and IgM antibodies.     

Mannose-binding lectin does not explain the course and outcome of pregnancy in rheumatoid arthritis

Introduction  

Rheumatoid arthritis (RA) improves during pregnancy and flares after delivery. It has been hypothesized that high levels of the complement factor mannose-binding lectin (MBL) are associated with a favourable disease course of RA by facilitating the clearance of pathogenic immunoglobulin G (IgG) lacking galactose sugar moieties. During pregnancy, increased galactosylation of IgG and simultaneously increased MBL levels can be observed, with the latter being strictly related to maternal MBL genotypes. Therefore, increased MBL levels in concert with increased IgG galactosylation may be associated with pregnancy-induced improvement of RA. The objective of this study was to investigate whether MBL genotypes are associated with changes in RA disease activity and with changes in IgG galactosylation during pregnancy and in the postpartum period. We also studied the association between MBL genotypes and pregnancy outcomes in RA.     

Endogenous glucocorticoids play a positive regulatory role in the anti-keyhole limpet hemocyanin in vivo antibody response

Glucocorticoids (GCs) are commonly reported to be immunosuppressive. Studies that support this involve the administration of synthetic GCs such as dexamethasone at high pharmacological doses and using in vitro assay systems that may have limited relevance to the role of GCs during normal in vivo immune responses. Therefore, the following experiments tested the conclusion that GCs are generally immunosuppressive. Adult male Sprague Dawley rats received adrenalectomy (ADX) or sham surgery. ADX rats were given either basal corticosterone (CORT) replacement in their drinking water (25 microg/ml) or no CORT. Rats were immunized with keyhole limpet hemocyanin (KLH), and blood samples were taken. ADX rats with no CORT replacement had reduced anti-KLH IgM and IgG responses compared with sham-operated controls. ADX rats that received basal CORT replacement had partially restored anti-KLH IgM, but still had suppressed anti-KLH IgG. Administration of GC receptor type I (RU28318) and type II (RU40555) receptor antagonists also reduced the anti-KLH IgM and IgG responses. ADX rats that received both basal CORT replacement and low dose injections of CORT on days 5 and 7 after KLH had anti-KLH IgG levels equal to those of sham-operated controls. Finally, the GC elevation 4-7 days after immunization may play a role in stimulating the IgM to IgG2a switch. GC receptor blockade reduced the anti-KLH IgG2a and splenic IFN-gamma, but not the anti-KLH IgG1, response. Given that IFN-gamma is an important regulator of the IgM to IgG2a switch, it is possible that the small rise in GC found 4-7 days after KLH facilitates IgG2a isotype switching.     

Vulnerability of placental antibody transfer and fetal complement synthesis to disturbance of the pregnant monkey

Maternal and fetal/infant antibody levels were assessed across pregnancy and at birth to evaluate the prenatal transmission of IgG in the rhesus monkey. Although some antibody was evident in the fetus by midpregnancy, the marked increase in IgG occurred primarily during the last two weeks of pregnancy. This delay until the end of pregnancy would result in low antibody titers in premature infants. In contrast, when gestation length was normal, the placental transfer of IgG was resistant to both dexamethasone treatment and a prolonged period of stress during pregnancy. This resiliency occurred despite an effect of prenatal stress on other aspects of infant development, including physical growth and the fetal synthesis of complement proteins.     

新生儿ABO 溶血病相关危险因素的临床分析

目的:分析新生儿ABO溶血病的临床相关危险因素,提高对新生儿ABO溶血病的防治水平。方法:选择ABO血型不合的孕妇433例,根据以上产妇产前IgG抗A(B)效价、产妇妊娠次数和产妇年龄分别分组,分析各组产妇间发生新生儿溶血病(HDN)的差异及临床相关性。结果:产妇产前IgG抗A(B)效价、产妇妊娠次数和产妇年龄均与HDN发生率呈正相关性(P<0.05);IgG抗A(B)效价>256时,HDN发生率将显著提高(P<0.01);产妇妊娠次数和年龄增加后,HDN发生率将显著增加(P<0.01)。结论:夫妻血型不合的产妇进行产前保健时,应进行IgG抗A(B)效价检查,当IgG抗A(B)效价>64或IgG抗A(B)效价进行性增加时,应及早做好HDN的干预措施;通过减少意外妊娠及高龄产妇数量,可减少HDN的发生。     

冻融胚胎移植中三种不同内膜准备方法的妊娠结局比较

目的：比较三种不同内膜准备方法中复苏胚胎移植的妊娠结局。方法：对因女方输卵管因素不孕的248个冻融囊胚移植周期的临床资料进行回顾性分析。将内膜准备方法分为自然周期组、全激素替代周期组和半激素替代周期组三种,分别对各组的着床率、临床妊娠率、生化妊娠率和早期流产率进行分析比较。结果：自然周期组的子宫内膜厚度显著高于全激素周期组和半激素替代周期组（P〈0．05）,差异有统计学意义。而这三组病人在年龄、不孕年限和移植胚胎数目上则均无明显差异（P〉0．05）。另外,三种内膜准备方法的着床率、临床妊娠率、早期流产率及生化妊娠流产率亦无显著性差异（P〉O．05）。结论：冻融胚胎移植中,对于排卵正常患者我们建议采用自然周期法更为经济、方便。而对于月经周期不正常,排卵障碍的病人应依实际情况采用全激素周期或半激素周期方案。     

Persistent Low Toxoplasma IgG Avidity Is Common in Pregnancy: Experience from Antenatal Testing in Norway

The parasite Toxoplasma gondii might harm the fetus if a woman is infected during pregnancy. IgG seroconversion and significant increase in IgG antibody amount in pregnancy indicates maternal infection. Presence of toxoplasma immunoglobulin M (IgM), immunoglobulin G (IgG) and low IgG avidity in a single serum sample indicates possible maternal infection, but positive toxoplasma IgM and low IgG avidity may persist for months and even years. We aimed to evaluate avidity development during pregnancy in a retrospective study. Serial blood samples from 176 pregnant women admitted to Oslo University Hospital 1993–2013 for amniocentesis because of suspected toxoplasma infection were included. Data were obtained from journals and laboratory records. The avidity method used was based on Platelia Toxo IgG assay. Mean maternal age at first serology was 29.9 years (SD 5.2, range 18–42). In 37 (21%) women only the avidity increased from low to high in < 3 months. In 139 (79%) the IgG avidity remained below the high threshold ≥ 3 months and within this group 74 (42%) women had stable low IgG avidity during the observation period. Median gestational age at first test was 10.6 weeks (range 4.6–28.7). Fetal infection was detected in four children, but none among children whose mother had stable low IgG avidity. The first antenatal toxoplasma serology should ideally be collected in early pregnancy and if stable values of toxoplasma IgM and low IgG-avidity are detected in a second sample after three to four weeks, the need for amniocentesis can be questioned.     

Cytomegalovirus Seroprevalence in Pregnant Women and Association with Adverse Pregnancy/Neonatal Outcomes in Jiangsu Province,China

Background

In this study, we aimed to determine the provincial population-based seroprevalence in pregnant women and to further explore the association of maternal CMV infection status and adverse pregnancy/neonatal/growth outcomes in Jiangsu, China.

Methods

In this case-control study, the sera from 527 pregnant women with adverse pregnancy/neonatal outcomes and 496 mothers of healthy infants in Jiangsu Province, collected at gestation age of 15–20 weeks, were tested for anti-CMV IgG, IgM and IgG avidity. Adverse pregnancy/neonatal outcomes were identified based on pregnancy/neonatal outcomes.

Results

The overall seroprevalence of anti-CMV IgG was 98.7%, with 99.4% and 98.0% in the case and control groups, respectively (P = 0.039). The prevalence of anti-CMV IgG+/IgM+, was higher in the case group than that in the control group (3.8% vs. 1.6%, P = 0.033). Anti-CMV IgG avidity assay showed that none in the control group were primarily infected, but five (0.9%) in the case group underwent primary infection (P = 0.084); all five infants of these women presented severe adverse neonatal/growth outcomes. Exact logistic regression analysis showed that anti-CMV IgG+/IgM+ was associated with adverse pregnancy/neonatal/growth outcomes (aOR = 2.44, 95% CI 1.01–6.48, P = 0.047). Maternal low education level and prior abnormal pregnancies also were risk factors for adverse pregnancy/neonatal outcomes.

Conclusions

In populations with very high prevalence of latent CMV infection, active maternal CMV infection during pregnancy might be a risk factor for adverse pregnancy/neonatal outcomes.     

Idiopathic thrombocytopenic purpura in pregnancy and neonatal period

In pregnancy and neonatal period both mother and child are endangered by bleeding complications due to maternal idiopathic thrombocytopenic purpura. Obstetrical and perinatal management therefore must aim at increasing maternal and fetal platelet count. In our paper six patients in nine pregnancies are reported. Two of them (five pregnancies) were treated with corticosteroids, four of the patients were successfully treated with i.v. immunoglobulins (IgG). Longterm steroid application and splenectomy during pregnancy may be hazardous for mother and fetus. IgG i.v. administration in contrast offers a new and safe way to control maternal and fetal platelet counts during pregnancy, delivery and the neonatal period.     

Prevalence and avidity of human herpesvirus-6 specific IgG antibodies in pregnant women in Hungary

The prevalence, the level and the avidity of human herpesvirus-6 (HHV-6) specific IgG were examined in pregnant women and age-matched female blood donors. The study group consisted of 180 women (age 14-45); 60 women with normal pregnancy, 60 pregnant women with fetuses suspected of having any viral infection and 60 healthy blood donors with no history of pregnancy. Plasma or serum samples were tested for HHV-6 IgG antibodies by an immunofluorescence assay. Ninety-eight percent of blood donors and 97% of 120 pregnant women had IgG antibodies to HHV-6. The rate of seropositivity in women with normal pregnancies and women with fetuses suspected to have viral infection was the same. Pregnant women (n = 120) had significantly lower antibody titer than blood donors. No significant differences were found in the same respect between the two groups of pregnant women. Low avidity of IgG antibodies to HHV-6 was detected in 5% of pregnant women.     

Use of IgG Avidity test in case definitions of toxoplasmosis in pregnancy

A survey network for congenital toxoplasmosis (TOXO-NET) was set up in December 1996 in Piedmont (Italy). Participants were asked to classify the infections in pregnant mothers and newborns by the criteria of the European Network on Congenital Toxoplasmosis published by Lebech in 1996. Because the IgG Avidity test is largely employed as a 2nd level test in toxoplasmosis diagnosis and it could be helpful to date infection, the co-ordinators of TOXO-NET suggested including it in the "case definition" of "probable" infection and "unlikely" infection. 117 cases of toxoplasmosis in pregnancy divided into the risk categories under Lebech's criteria were re-examined using the "new" case definitions. 77 out of 117 (65.8%) Toxoplasma gondii infections during pregnancy could be defined with only one serum sample using the IgG Avidity test. The IgG Avidity test proved a useful method to classify the Toxoplasma gondii infections in pregnancy, especially when we had only one serum sample.     

Plasmodium falciparum malaria mimicking autoimmune hemolytic anemia during pregnancy.

A 30-year-old woman contracted Plasmodium falciparum malaria in the first trimester of her pregnancy while taking chloroquine for malaria prophylaxis. Her illness was characterized by hemolytic anemia with IgG1 coating of the surface of the erythrocytes and IgG3 in her serum. The hemolysis subsided following treatment of the malaria infection early in the third trimester. She delivered at term an infant who had hypoplasia of the right tibia and fibula and absence of the fifth ray of the right foot. The hemolytic process was attributed to the malaria infection, and the birth defect may have been related to the antimalarial therapy in the first trimester of pregnancy.     

Glycosylation profiling of immunoglobulin G (IgG) subclasses from human serum

All four subclasses of human serum IgG contain a single N-glycosylation site in the constant region of their heavy chain, which is occupied by biantennary, largely core-fucosylated and partially truncated oligosaccharides, that may carry a bisecting N-acetylglucosamine and sialic acid residues. IgG glycosylation has been shown to be altered under various physiological and pathological circumstances. IgG N-glycan profiles vary with age, and galactosylation for example is enhanced during pregnancy. Several diseases including rheumatoid arthritis are associated with a reduction in galactosylation of the IgG N-glycans. Here, we describe a robust method for the isolation of IgG subclasses using protein A (binds IgG1, IgG2, and IgG4) and protein G (binds additionally IgG3) at the 96-well plate level, which is suitable for automation. Isolated IgGs were digested with trypsin, and obtained glycopeptides were analyzed by nano-LC-MS. Glycopeptides were characterized by CID as well as electron transfer dissociation (ETD). The method provided glycosylation profiles for IgG1, IgG2, IgG3, and IgG4 and revealed distinct differences in N-glycosylation between the four IgG subclasses. The changes in galactosylation associated with rheumatoid arthritis could readily be monitored. This method is suitable for the subclass-specific analysis of IgG glycosylation from clinical samples.     

Influence of the embryo on the distribution of maternal immunoglobulins in the mouse uterus

The effect of the embryo on the distribution of IgA, IgG and IgM was studied by an immunoperoxidase technique on mouse uterine sections, (1) during the first part of pregnancy and pseudopregnancy, and (2) in delayed implantation combined with different progesterone-oestradiol treatments designed to extend the delay or induce implantation, and in nonpregnant ovariectomized mice similarly treated. The number of glandular lumina containing IgA increased particularly from the implantation period, but in pseudopregnancy this number decreased from the morning of Day 4, and afterwards continued to decline. In delayed implantation, the number of glandular lumina containing IgA also rose considerably when implantation was induced by oestradiol, whereas under the same progesterone-oestradiol treatment, nonpregnant ovariectomized animals displayed no such increase. Significant staining for IgG in the stroma was observed on Day 4 of pregnancy and pseudopregnancy but prolonged staining for IgG was observed only during pregnancy. In addition, significant numbers of IgA-plasma cells in the stroma were observed mostly in uteri containing embryos. These results indicate that embryos might affect the process by which ovarian hormones regulate IgA and IgG distribution.     

Secreted and placental membrane forms of folate-binding protein occur sequentially during pregnancy in swine

The objective was to understand how two forms of folate-binding protein interact to accomplish folate transport during pregnancy in swine. Specific folate binding was measured in uterine flushings during the estrous cycle and early pregnancy and in allantoic fluid (secreted form) and placental membranes (membrane form) throughout later pregnancy. In addition, the localization of the secreted form of folate-binding protein (sFBP) in uterine wall sections was assessed. Uterine flushings were collected on Days 10, 13, and 15 of the estrous cycle and pregnancy. Allantoic fluid and placentas were collected on Days 20, 35, 50, 70, 90, and 105 of pregnancy. Uterine-wall sections were collected on all days of the experiment. Folate binding was measured by incubation of aliquots of uterine flushings, allantoic fluid, or placental microsomal membranes with 0.5-4 nM [(3)H]folate. Uterine-wall sections were incubated with purified anti-FBP IgG or normal rabbit serum IgG to localize sFBP. Folate binding did not differ between early pregnancy and the estrous cycle in uterine flushings, was greatest from Day 50 to 70 of pregnancy in allantoic fluid, and was greatest from Day 50 of pregnancy onward in placental microsomal membranes. Staining for sFBP was present in the endometrial glands from Day 10 to 15 in cyclic gilts and from Day 10 to 20 in pregnant gilts. The pattern of folate binding and sFBP staining supports the concept that sFBP transports folate to the developing conceptus until placentation and then the placental form takes over folate transport.     

Performance of the immunoglobulin G avidity and enzyme immunoassay IgG/IgM screening tests for differentiation of the clinical spectrum of toxoplasmosis

Toxoplasmosis has been well known as an important human infection to consider especially in pregnant women. Although many serologic methods are available, the diagnosis of toxoplasmosis can be extremely difficult. The presence of increased levels of Toxoplasma-specific IgG antibodies indicates an infection, but it does not differentiate between a recent and past infection. The purpose of our study was to compare the performance of the ELISA T. gondii IgG/IgM test, a widely used enzyme-linked immunosorbent assay, to the ELISA IgG avidity method. One hundred and four serum samples (from 38 males and 66 females) were tested and evaluated from symptomatic patients (chorioretinitis, lymphadenopathy), and from women in their first trimester of pregnancy who were suspected of having toxoplasmosis. The high IgG avidity and ELISA IgG antibody levels were in agreement for 51 of the specimens (49.0%). Thirty-eight discrepant (borderline) results from the IgG avidity method were positive for IgM (3 specimens) and IgG (37 specimens). Interestingly, out of the eight serum samples that were positive for both IgG and IgM antibodies, two samples were low IgG avidity, and three samples were borderline. There was no statistically significant relation observed between the results of the IgG avidity method and the ELISA IgG test, and the IgG avidity method and ELISA IgM test (chi2 = 1.987; p = 0.370 and chi2 = 2.152; p = 0.341, respectively). The IgG avidity method was considered easy to perform and an acceptable approach for the differentiation of discrepant results (recent/chronic) and for the current detection of T. gondii antibodies. We concluded that the determination of IgG avidity is a helpful tool for the diagnosis of the ocular form of toxoplasmosis and it is a safe method for screening this disease in the first trimester of pregnancy.     

Relative stabilities of IgG1 and IgG4 Fab domains: Influence of the light-heavy interchain disulfide bond architecture

The stability of therapeutic antibodies is a prime pharmaceutical concern. In this work we examined thermal stability differences between human IgG1 and IgG4 Fab domains containing the same variable regions using the thermofluor assay. It was found that the IgG1 Fab domain is up to 11°C more stable than the IgG4 Fab domain containing the same variable region. We investigated the cause of this difference with the aim of developing a molecule with the enhanced stability of the IgG1 Fab and the biological properties of an IgG4 Fc. We found that replacing the seven residues, which differ between IgG1 C(H) 1 and IgG4 C(H) 1 domains, while retaining the native IgG1 light-heavy interchain disulfide (L-H) bond, did not affect thermal stability. Introducing the IgG1 type L-H interchain disulfide bond (DSB) into the IgG4 Fab resulted in an increase in thermal stability to levels observed in the IgG1 Fab with the same variable region. Conversely, replacement of the IgG1 L-H interchain DSB with the IgG4 type L-H interchain DSB reduced the thermal stability. We utilized the increased stability of the IgG1 Fab and designed a hybrid antibody with an IgG1 C(H) 1 linked to an IgG4 Fc via an IgG1 hinge. This construct has the expected biophysical properties of both the IgG4 Fc and IgG1 Fab domains and may therefore be a pharmaceutically relevant format.     

Antibodies against beta 2-glycoprotein I (beta 2-GP I) and their relationship to fetoplacental antigens

Binding of beta 2-GP I to anionic phospholipids is thought to be the major antigen required in the reaction of anticardiolipin antibodies to phospholipids. The aim of this study was to investigate the changes of anti-beta 2-GP I IgG during the first and second trimester of pregnancy and the relationship between the levels of anti-beta 2-GP I and fetoplacental antigens and the correlation between anti-beta 2-GP I IgG and antibodies against oxidized low-density lipoprotein IgG (oLAb) in serum of pregnant women. We determined anticardiolipin antibodies (ACA) IgG and maternal serum levels of alpha 1-fetoprotein (AFP), human chorionic gonadotrophin (HCG) and trophoblast-specific beta 1-glycoprotein (SP1) in 204 pregnant women in the first and second trimester. From this group we selected 52 serum samples positive for ACA IgG and 16 samples negative for ACA IgG. In the samples of selected patients, the levels of anti-beta 2-GP I IgG and oLAb IgG were determined. Anti-beta 2-GP I IgG levels significantly decreased in the second trimester (6.2+/-9.3 U/ml, mean +/- S.D.) in comparison with the first trimester (8.3+/-10.4 U/ml) (p=0.05). Multiple of median (MoM) AFP correlated negatively but not significantly in the first trimester with anti-beta 2-GP I (r = -0.261, p = 0.12). In the second trimester this correlation was significantly negative (r = -0.278, p = 0.04). The Spearman correlation coefficients for MoM HCG and anti-beta 2-GP I were 0.158 for the first trimester and 0.174 for the second trimester. MoM SP1 also did not correlate significantly with anti-beta 2-GP I in both trimesters. The correlation between anti-beta 2-GP I IgG and oLAb IgG was not significant (r = -0.06). In the first trimester 40 % serum samples were positive for anti-beta 2-GP I IgG and negative for oLAb IgG or vice versa, while 60 % samples in the second trimester were positive only for one determined autoantibody. We can conclude that the levels of anti-beta 2-GP I IgG decrease during the second trimester probably as the result of the effects of some immunosuppressive agents associated with pregnancy. The finding of negative correlation between AFP and anti-beta 2-GP I suggests that anti-beta 2-GP I has an influence on fetus development.