Lipoteichoic acid stimulates the proliferation, migration and cytokine production of adult dental pulp stem cells without affecting osteogenic differentiation.

AIM: To model in vitro the contact between adult dental pulp stem cells (DPSCs) and lipoteichoic acid (LTA), a cell wall component expressed at the surface of most Gram-positive bacteria. METHODOLOGY: Human DPSCs obtained from impacted third molars were cultured and exposed to various concentrations of S. aureus LTA (0.1, 1.0 and 10 µg mL-1 ). The effects of LTA on DPSCs proliferation and apoptosis were investigated by MTT assay and flow cytometry. Mineralization of DPSCs was evaluated by alizarin red staining assay. Migration was investigated by microphotographs of wound-healing and Transwell migration assays. Reverse transcription polymerase chain reaction was used to examine the effects of LTA on p65 NF-κB translocation and TLR1, TLR2 or TLR6 regulation. Enzyme-linked immunosorbent assay was used to investigate LTA-stimulated DPSCs cytokine production. One-way or two-way ANOVA and Tukey post hoc multiple comparison were used for statistical analysis. RESULTS: DPSCs expressed TLR1, TLR2 and TLR6 involved in the recognition of various forms of LTA or lipoproteins. Exposure to LTA did not up- or down-regulate the mRNAs of TLR1, TLR2 or TLR6 whilst LPS acted as a potent inducer of them [TLR1 (P ≤ 0.05), TLR2 (P ≤ 0.001) and TLR6 (P ≤ 0.001)]. Translocation of p65 NF-κB to the nucleus was detected in LTA-stimulated cells, but to a lesser extent than LPS-stimulated DPSCs (P ≤ 0.001). The viability of cells exposed to LTA was greater than unstimulated cells, which was attributed to an increased proliferation and not to less cell death [LTA 1 µg mL-1 (P ≤ 0.001) and 10 µg mL-1 (P ≤ 0.01)]. For specific doses of LTA (1.0 µg mL-1 ), adhesion of DPSCs to collagen matrix was disturbed (P ≤ 0.05) and cells enhanced their horizontal mobility (P ≤ 0.001). LTA-stimulated DPSCs released IL-6 and IL-8 in a dose-dependent manner (P ≤ 0.0001). At all concentrations investigated, LTA did not influence osteogenic/odontoblastic differentiation. CONCLUSIONS: Human DPSCs were able to sense the wall components of Gram-positive bacteria likely through TLR2 signalling. Consequently, cells modestly proliferated, increased their migratory behaviour and contributed significantly to the local inflammatory response through cytokine release.

Differential IFN-γ production by adult and neonatal blood CD56+ natural killer (NK) and NK-like-T cells in response to Trypanosoma cruzi and IL-15.

Early interferon-gamma (IFN-γ) release by innate cells is critical to direct type 1 immune response able to control intracellular pathogens like Trypanosoma cruzi. Although CD56(bright) natural killer (NK) cells are reported to be potent early IFN-γ producers, other CD56(+) cells like CD56(dim) NK cells and NK-like T cells have recently been shown to also release IFN-γ. We have here studied the contribution of each CD56(+) lymphocyte populations in early IFN-γ production in both adults and neonates. On this purpose, we analysed the kinetics of IFN-γ production by RT-PCR, ELISA and flow cytometry from 2 h onwards after T. cruzi and IL-15 stimulation and sought for the responding CD56(+) cells. CD56(bright) and CD56(dim) CD16(-) NK cells were the more potent IFN-γ early producers in response to IL-15 and parasites in adults and neonates. In both age groups, the majority of IFN-γ producing cells were NK cells. However, on the contrary to neonates, CD3(+) CD56(+) NK-like T cells and CD3(+) CD56(-) 'classical' T cells also contributed to early IFN-γ production in adults. Altogether, our results support that whereas NK cells responded almost similarly in neonates and adults, cord blood innate CD56(+) and CD56(-) T cells displayed major quantitative and qualitative defects that could contribute to the well-known neonatal immune immaturity.

Interactions between chronic murine Trypanosoma cruzi infection and pregnancy: fetal growth retardation.

Fetal growth, reproductive capacity, and parasitemia were studied in three groups of BALB/c mice: pregnant and chronically infected with Trypanosoma cruzi, non-pregnant but similarly infected, and pregnant but noninfected. The pregnant mice were killed on day 17 of pregnancy. Comparisons of the two pregnant groups showed significant differences in fetal weights and x18 magnified ossification lengths of radius and cubitus, whereas placental weights were not modified. The results indicate that intrauterine growth retardation occurs during chronic murine T. cruzi infection. No difference was noted between the reproductive capacities of the two pregnant groups. Parasitemias were similar in infected pregnant and control groups. Mice of all groups survived infection until killing. Pregnancy, therefore, does not influence chronic murine T. cruzi infection. Parasites were never found in fetal blood, indicating a very low, if any, frequency of transplacental transmission of parasite during the chronic phase of infection.

Chagas' disease: decreased resistance to Trypanosoma cruzi acquired infection in offspring of infected mice.

The course of Trypanosoma cruzi infection was studied in an experimental model, using the offspring of mice that were chronically infected with T. cruzi. When infected two months after birth, a higher mortality rate in heavily parasitized mice occurred in these offspring than in controls born to uninfected mothers. The harmful maternal influence reached a maximum when offspring were exposed both to prenatal (placental) and postnatal (lactating) influences. It was a reversible phenomenon that led to a T. cruzi-specific failure of the offspring to control the acute phase of the infection. Such features are suggestive of a maternally-induced impairment of the immune response of the offspring.

Influence of maternal infection on offspring resistance towards parasites.

Immunoglobulins, parasite circulating antigens, immune cells, cytokines and other cell-related products can be transferred from infected mothers to their young. They can combine their effects to interact with the invading parasites, as well as to induce a long-term modulation of the offspring's capacity to mount an immune response to subsequent exposure to parasites. The protective effect of maternally derived antibodies may be limited by the selective transfer of immunoglobulin isotypes. Maternal antibodies may also prevent the priming of specific cells in offspring or inhibit the progeny's antibody production by interacting with B-cell receptors or with the idiotypic repertoire. The potentially beneficial priming effect of transferred parasitic antigens may be altered by the Th2-cell-biased foetal environment and such antigens may also induce deletion or anergy of T- and B-cell clones in offspring. Therefore, besides protective effects, maternal infection may downregulate the offspring's immune response. If such hyporesponsiveness may be clearly harmful (in increasing the risk or in worsening congenital or postnatally acquired infections in offspring), it can also be beneficial (in limiting the pathogenesis of some infections). Here, Yves Carlier and Carine Truyens review the rationale of these complex foeto-maternal relationships in parasitic diseases.

High circulating levels of fibronectin and antibodies against its RGD adhesion site during mouse Trypanosoma cruzi infection: relation to survival.

The levels of fibronectin (FN), a multifunctional glycoprotein known to mediate in vitro Trypanosoma cruzi-host cell adhesion, were measured in the plasma of T. cruzi-infected BALB/c mice. The infection induced a long-lasting increase of fibronectin levels during the acute parasitemic phase of the disease. Immunoblotting analysis showed the occurrence of lower-molecular-size FN fragments in the plasma of acutely infected animals, suggesting an infection-related FN degradation. FN levels were found to be significantly lower in dying mice harboring higher parasitemias than in surviving animals. A weak level of natural IgM against the RGD adhesion site of FN was detected before and during the first 3 weeks of infection. The level was significantly higher in surviving mice. From the fourth week postinfection, a significant increase in the levels of anti-RGD antibodies coincided with a decrease of circulating FN. These antibodies were mainly of the IgM, IgG1, and IgG2a isotypes. Taken together, these data suggest that both FN and anti-FN antibodies may contribute to the outcome of T. cruzi infection in mice.

Acute Trypanosoma cruzi infection: IL-12, IL-18, TNF, sTNFR and NO in T. rangeli-vaccinated mice.

We have developed an experimental model of vaccination against the infection with the protozoa Trypanosoma cruzi, the agent of Chagas disease in Latin America. Vaccination was performed with Trypanosoma rangeli, a non-pathogenic protozoa sharing many antigens with T. cruzi. It strongly protected BALB/c mice, sharply reducing parasitaemia and mortality rate of the acute T. cruzi infection. The aim of the present work was to complete our previous study on the production of IFN-gamma and IL-10 in this vaccination model by investigating the production of IL-12p35 and p40, IL-18, TNF, TNF soluble receptors (sTNFR), and nitric oxide (NO), factors known to play a key role in the outcome of T. cruzi infection. We show that the protection obtained against the acute T. cruzi infection was surprisingly associated with reduced circulating levels of IL-18 and NO, whereas the release of IL-12p40 was enhanced in comparison to non-vaccinated infected animals. IL-12p35 remained undetectable in infected animals, vaccinated or not. The balance between sTNFR and TNF suggested a decrease of TNF bioactivity in vaccinated mice. These results show that the protection induced by the vaccination with T. rangeli against a challenging infection with T. cruzi is not associated with the strong type 1 immune response usually involved in the control of intracellular pathogens, particularly questioning the protective role of NO during the acute phase of T. cruzi infection.

Trypanosoma cruzi infection in mice induces a polyisotypic hypergammaglobulinaemia and parasite-specific response involving high IgG2a concentrations and highly avid IgG1 antibodies.

Trypanosoma cruzi infection in BALB/c mice induced a reversible polyisotypic hypergammaglobulinaemia, with particularly high levels of IgG2a, IgM and IgE. Hypergammaglobulinaemia started during the acute phase of infection and persisted during chronic disease until 11-13 weeks post-infection (w.p.i.), when immunoglobulin levels, with the exception of IgE, returned near normal values. Parasite-specific antibodies counted for 14 to 23% of gammaglobulinaemia, in acute and chronic infection respectively. The titres of IgM antibodies rose from two w.p.i. IgA, IgE and IgG subclass antibodies built up gradually over the time of parasite clearance (i.e., between three and six w.p.i.). All antibody isotypes, including IgM reached significant and stable titres throughout chronic infection. IgG2a, IgG1 and IgM antibodies had constantly higher titres than the other antibody isotypes. The dominance of IgG2a antibodies was due to their high plasma concentrations, around 70% of all antibodies available in the chronic infection. IgG1 had the highest functional avidity, whereas its concentration corresponded to only 10% of the whole antibody fraction. These results indicate that T. cruzi infection in mice induces a polyisotypic humoral immune response, dominated by some antibody isotypes, with major differences in concentrations and functional avidities. This could be of crucial importance in determining the outcome of infection.

Demonstration of the presence of IL-16, IL-17 and IL-18 at the murine fetomaternal interface during murine pregnancy.

PROBLEM: To determine if interleukin-16 (IL-16), IL-17, and IL-18 are present at the murine fetomaternal interface during pregnancy as a first step towards investigating their roles in fetomaternal relationship. METHODS: Expression of IL-16, IL-17, and IL-18, was assessed by immunohistochemistry (IHC) in the BALB/c x BALB/k (H2d x H2k), and the CBA/J x BALB/c non-abortion prone, and CBA/J x DBA/2 abortion prone matings. Enzyme-linked immunosorbent assay (ELISA) were performed for the two latter cytokines to compare local production in the abortion prone CBA/J x DBA/2 versus the non-abortion prone CBA/J x BALB/c matings. RESULTS: Expression of IL-17 was borderline. The anti-IL-16 staining specifically localized in the uterine stroma and glandular epithelium and was rather low in the placenta. IL-18 staining started in the peri-implantation uterus in the basal proliferative stroma, and was also traced, although weaker, in the glandular epithelium. In the immediate post-implantation period, a weak stromal staining persisted but there was a strong labeling of the ectoplacental cone. Interestingly, when the ectoplacental cone differentiates into placenta having a major histocompatibility complex (MHC) class I + spongiotrophoblast and a (MHC class I-) labyrinth, a very strong transient labeling of uterine natural killer (u-NK) cells was found. Later in gestation, IL-18 was also produced by giant cell and spongiotrophoblast. Finally, we compared by ELISA the production of IL-17/-18 in CBA/J x DBA/2 and CBA/J x BALB/c matings. We detected significantly more IL-18 in the non-abortion prone combination decidua or placenta. CONCLUSION: The three cytokines IL-16, IL-17, and IL-18 were detected at the fetomaternal interface with a tissue specific, stage-dependent distribution. The predominance of IL-18 secretion in the non-resorption prone matings lead us to question the general validity of the classical T-helper (Th)1/2 paradigm.

IL-10 up-regulates nitric oxide (NO) synthesis by lipopolysaccharide (LPS)-activated macrophages: improved control of Trypanosoma cruzi infection.

We examined the effects of IL-10 on tumour necrosis factor-alpha (TNF-alpha) and NO production by LPS-activated macrophages and on the ability of these cells to control Trypanosoma cruzi infection. We first observed that the addition of rIL-10 to macrophages of the J774 cell line decreased their synthesis of TNF-alpha but increased their release of NO in a dose-dependent manner. In parallel, treatment of J774 cells with rIL-10 resulted in a better control of T. cruzi infection involving up-regulation of NO synthesis, as it was not observed in presence of N-nitro-L-arginine methyl ester (L-NAME), a competitive inhibitor of NO synthase. The enhancing effect of rIL-10 on NO production was not observed on peritoneal macrophages from wild-type C57Bl/6 mice, but well on macrophages from IL-10 knock-out mice. The control of NO production by endogenous IL-10 was confirmed by the demonstration that neutralization of IL-10 secreted by LPS-activated macrophages from wild-type mice inhibited their production of NO and, in parallel, their ability to control T. cruzi infection. Taken together, these data demonstrate that both exogenous and endogenous IL-10 up-regulate the production of NO by LPS-activated macrophages and improve thereby their ability to clear T. cruzi infection.

Interleukin-6 (IL-6) production in mice infected with Trypanosoma cruzi: effect of its paradoxical increase by anti-IL-6 monoclonal antibody treatment on infection and acute-phase and humoral immune responses.

Trypanosoma cruzi infection of mice triggered endogenous production of interleukin-6 (IL-6) during the ascending phase of parasitemia. Injections of anti-IL-6 monoclonal antibody in infected mice at the time of the serum IL-6 peak paradoxically increased IL-6 levels to 60- to 80-fold those in infected mice receiving unrelated immunoglobulins. This early and transient increase in circulating IL-6 levels modified neither the immunoglobulin nor T. cruzi-specific antibody levels of immunoglobulin G1 (IgG1), IgG2a, IgG3, IgM, IgA, and IgE isotypes or the final outcome of infection nor the blood or tissular parasite levels. However, it tended to delay mortality of mice and to increase the levels of the acute-phase protein serum amyloid P component.

The endogenous balance of soluble tumor necrosis factor receptors and tumor necrosis factor modulates cachexia and mortality in mice acutely infected with Trypanosoma cruzi.

To better understand the role of tumor necrosis factor (TNF) during Trypanosoma cruzi infection in BALB/c mice, we have investigated the kinetics of circulating tumor necrosis factor (TNF), soluble TNF receptor 1 (sTNR1), and sTNFR2 levels, as well as the interactions between such factors, in relation to parasitemia, cachexia, and mortality of acutely infected animals. Our data show that the parasitemic phase of T. cruzi infection in mice is associated with high levels of circulating TNF and sTNFR2, resulting in the formation of cytokine-receptor complexes and some degree of neutralization of TNF bioactivity. Although sTNR2 levels always exceeded TNF levels, low sTNFR/TNF circulating ratios were associated with cachexia in all infected mice, whereas the lowest ratios were observed in dying animals harboring the highest parasitemia. We also studied the modulation of sTNFR/TNF ratios induced by anti-TNF antibodies administered to infected animals and their consequences on the outcome of the infection. The injection of anti-TNF monoclonal antibody (MAb) TN3 into infected mice resulted in a paradoxical overproduction of TNF (associated with a higher parasitemia), lowered the sTNFR/TNF circulating ratios, and considerably worsened cachexia and mortality of animals. Another anti-TNF MAb (1F3F3) decreased the in vivo availability of TNF as well as parasite levels and reduced cachexia. Altogether, such results highlight that, besides playing a beneficial role early in infection, TNF also triggers harmful effects in the parasitemic phase, which are limited by the in vivo simultaneous endogenous production of soluble receptors.

The cachexia associated with Trypanosoma cruzi acute infection in mice is attenuated by anti-TNF-alpha, but not by anti-IL-6 or anti-IFN-gamma antibodies.

BALB/c male mice acutely infected with Trypanosoma cruzi underwent a severe weight loss (around 20%, from day 18 to 31 post-infection), when compared to age-matched uninfected animals. Though mice regained weight later, when blood parasites were hardly detectable, wasting extended over the chronic phase of infection. The onset and the magnitude of weight loss were related to the mouse susceptibility to infection, since they were respectively earlier and higher in male mice which will die than in surviving ones, in males than in females, and in BALB/c than in B6D2 [(C57B1/6 x DBA/2)F1], a mouse strain more resistant to infection. Fat weight of infected mice (male BALB/c) was reduced by 60 to 80%, whereas lean mass was unaffected and water content rose by 6 to 10% in acute and chronic infection. Haematocrit was also decreased by 15-16% in acute infection. Animals failed to compensate their energetic loss since their food intake remained similar to that of uninfected animals. Injections of neutralizing anti-TNF-alpha monoclonal antibody into infected male mice, during the first two weeks but not later in infection, significantly attenuated the weight loss. Early administration of anti-IL-6 or anti-IFN-gamma MoAbs did not improve the mouse wasting. Taken together, these data show that TNF is a key agent of cachexia occurring in the acute T. cruzi infection in mice.

Pregnancy and humoral immune response in mice chronically infected by Trypanosoma cruzi.

The effect of pregnancy on the humoral immune response induced by Trypanosoma cruzi was studied in groups of chronically infected and pregnant mice (IP) or chronically infected and nonpregnant mice (INP) of strain BALB/c. Groups of noninfected and nonpregnant mice (NINP) or noninfected and pregnant mice (NIP) served as controls. The pregnant mice were killed on day 17 of pregnancy. Anti-T. cruzi immunoglobulin G (IgG) and IgM antibodies, detected by immunofluorescence or enzyme-linked immunosorbent assay or both, underwent a pregnancy-associated decrease of 20 to 40%, whereas complement-mediated lytic antibodies were unaffected by pregnancy. Immunoblotting analysis indicated identical specificities of the anti-T. cruzi antibodies in IP and INP groups. The levels of all the immunoglobulin isotypes (particularly IgG2a and IgG3), circulating immune complexes, rheumatoid-like factor, and anti-DNA antibodies were considerably increased during chronic infection (NINP versus INP), which could be related to the high degree of polyclonal B-cell activation occurring in T. cruzi infection. However, pregnancy significantly decreased (by 20 to 60%) such parameters. IgG levels were particularly affected (by 40 to 60%), and the decreases could be ordered as follows: IgG3 greater than IgG2a greater than IgG1 greater than IgG2b for IP versus INP. Comparisons between the noninfected groups indicated differences only in IgG levels. These results indicate the following. (i) The specific humoral anti-T. cruzi immune response is weakly affected by pregnancy, which is not sufficient to modify the course of the mother's infection. (ii) Pregnancy does not modify the expression of the anti-T. cruzi antibody repertory. (iii) Pregnancy reduces the polyclonal B-cell activation, particularly the levels of the IgG isotypes undergoing the greatest activation.

Maternal Trypanosoma cruzi infection upregulates capacity of uninfected neonate cells To produce pro- and anti-inflammatory cytokines.

The possibility of maternal in utero modulation of the innate and/or adaptive immune responses of uninfected newborns from Trypanosoma cruzi-infected mothers was investigated by studying the capacity of their whole blood cells to produce cytokines in response to T. cruzi lysate or lipopolysaccharide-plus-phytohemagglutinin (LPS-PHA) stimulation. Cells of such newborns occasionally released gamma interferon (IFN-gamma) and no interleukin-2 (IL-2) and IL-4 upon specific stimulation, while their mothers responded by the production of IFN-gamma, IL-2, and IL-4. Infection in mothers was also associated with a hyperactivation of maternal cells and also, strikingly, of cells of their uninfected neonates, since their release of proinflammatory (IL-1beta, IL-6, and tumor necrosis factor alpha [TNF-alpha]) as well as of anti-inflammatory (IL-10 and soluble TNF receptor) cytokines or factors was upregulated in the presence of LPS-PHA and/or parasite lysate. These results show that T. cruzi infection in mothers induces profound perturbations in the cytokine response of their uninfected neonates. Such maternal influence on neonatal innate immunity might contribute to limit the occurrence and severity of congenital infection.

High tumor necrosis factor alpha (TNF-alpha) production in Trypanosoma cruzi-infected pregnant mice and increased TNF-alpha gene transcription in their offspring.

Since tumor necrosis factor alpha (TNF-alpha) is known to be involved in the feto-maternal relationship, this cytokine was studied in Trypanosoma cruzi-infected pregnant BALB/c mice and their fetuses and offspring. Pregnant chronically infected mice displayed significantly higher levels of circulating TNF-alpha than animals either only infected or only pregnant. TNF-alpha was undetectable in sera of uninfected and nonpregnant mice as well as in breast milk obtained from infected and uninfected animals. Fetuses from infected mice exhibited significantly more cells containing TNF-alpha mRNA in their thymus than fetuses from uninfected mothers. When infected 2 months after birth, offspring born to infected and uninfected mothers displayed similar amounts of circulating TNF-alpha during chronic infection, whereas this cytokine was only weakly detectable during the acute phase of the disease. An intravenous injection of lipopolysaccharide during acute infection strongly increased the production of TNF-alpha in offspring born to infected mothers to levels higher than those in progeny from uninfected mice. These results suggest that TNF-alpha is an important cytokine in the feto-maternal relationship during T. cruzi infection and that fetuses and offspring of infected mothers are primed to produce elevated levels of TNF-alpha.

IFN-gamma-independent IgG2a production in mice infected with viruses and parasites.

After infection with some viruses and intracellular parasites, antibody production is restricted to IgG2a. We first observed that, whereas live viruses such as lactate dehydrogenase-elevating virus (LDV) or mouse adenovirus induced mostly an IgG2a response, a large proportion of antibodies produced against killed viruses were IgG1. This IgG1 antiviral response was suppressed when live virions were added to inactivated viral particles. These results indicate that the IgG2a preponderance is related to the infectious process itself rather than to the type of antigen involved. Since IFN-gamma is known to stimulate IgG2a production by activated B lymphocytes and to be secreted after infection, we examined the role of this cytokine in the antibody isotypic distribution caused by LDV. Most IgG2a responses were relatively unaffected in mice deficient for the IFN-gamma receptor or treated with anti-IFN-gamma antibody. A similar IFN-gamma-independent IgG2a secretion was observed after infection with the parasites Toxoplasma gondii and Trypanosoma cruzi. However, the IFN-gamma-independent IgG2a production triggered by infection still required the presence of functional T(h) lymphocytes. Therefore, signal(s) other than IFN-gamma secretion may explain the T(h)-dependent isotypic bias in antibody secretion triggered by viruses and parasites.

Estatus inmunológico de las madres infectadas por T. cruzi / Immunological status of mothers infected with Trypanosoma cruzi

The mechanisms of congenital transmission of Chagas disease remain largely unknown. To better understand the role of maternal immunology during pregnancy in congenital Chagas transmission, we studied the cytokine production and the parasitic load in three groups of mothers: infected mothers who transmitted the disease to their babies (M+B+-), infected mothers who did not transmit the disease to their babies (M+B-) and not infected mothers as a control group (M-B-). M+B+ mothers produced less IFNgamma and more IL-10 than the M+B- mothers, and they are not able to produce IL-2. M+B+ mothers showed a higher parasitic load. These results, indicated that the congenital Chagas transmission is associated with an immunological imbalance and a high parasitic load in the M+B+ mothers.

Respuesta inmune en neonatos no infectados nacidos de madres infectadas por Trypanosoma cruzi / Immune responses of non-infected neonates of mothers infected with Trypanosoma cruzi

We have investigated if maternal T. cruzi infection could induce in utero innate and/or adaptive immune responses in uninfected neonates by measuring specific IgM and IgA antibodies in cord blood plasma, and by performing phenotypic and functional studies of umbilical cord blood cells of their newborns (M+B- group). We detected T. cruzi-specific IgM and IgA antibodies in M+B- cord blood, indicating they had mounted in utero a strong B cell response, although they are not infected. On the other hand, circulating T cells of such uninfected neonates displayed a low level of activation, as seen bya slightly increased expression of the activation markers CD45RO on CD4+ T cells and HLA-DR on CD8+ T cells, although the proportion of CD4+ and CD8+ T cells was unmodified as compared to newborns from uninfected mothers (MB- group). This activation did not give rise to a proliferative response upon stimulation by T. cruzi antigens in vitro. However, M+B- cells produced low levels of lymphokines (IFN-gamma and IL-13) upon mitogenic stimulation, which was not the case of M-B- newborn cells. Beside this, M+B- blood cells produced higher levels of inflammatory cytokines (IL-1b, IL-6, TNF-alpha) than M-B- cells when stimulated with the T. cruzi lysate or LPS, suggesting the over-activation of the innate response in M+B- newborns. Monocytes participated in such inflammatory response since M+B- purified cord blood monocytes produced higher levels of TNF- when incubated with LPS or a T. cruzi lysate than M-B- cells. Altogether, these results show that, even in the absence of congenital infection, maternal T. cruzi infection triggers in utero both adaptive and innate immune responses in their babies. This indicates that parasite circulating antigens have been transferred from mothers to their fetuses.

Detección de la heterogeneidad molecular de Trypanosoma cruzi / Detection of molecular heterogeneity of Trypanosoma cruzi

Congenital transmission of T. cruzi in Cochabamba affects 6% of newborns from infected mothers. Only limited information is available on the type of transmitted parasites. However, it is well established that T. cruzi isolated from various vectors as well from host animals are highly heterogeneous. In our presentation we analyse aspects of molecular heterogeneity of T. cruzi and we review methods used for the molecular typing of T. cruzi lineages. Experimentally, we performed the PCR amplification of [quot ]Sequence-characterised region Markers[quot ] for typing T. cruzi isolated from umbilical blood of newborns in Cochabamba. We compared these results with those we obtained from general infected population. All 16 analysed, congenitally infected samples were of lineage IId. Our data also indicated that this lineage was found in about 80% of samples originated from general infected population in Cochabamba.