Hormones and B-cell development in health and autoimmunity.

The development of B cells into antibody-secreting plasma cells is central to the adaptive immune system as they induce protective and specific antibody responses against invading pathogens. Various studies have shown that, during this process, hormones can play important roles in the lymphopoiesis, activation, proliferation, and differentiation of B cells, and depending on the signal given by the receptor of each hormone, they can have a positive or negative effect. In autoimmune diseases, hormonal deregulation has been reported to be related to the survival, activation and/or differentiation of autoreactive clones of B cells, thus promoting the development of autoimmunity. Clinical manifestations of autoimmune diseases have been associated with estrogens, prolactin (PRL), and growth hormone (GH) levels. However, androgens, such as testosterone and progesterone (P4), could have a protective effect. The objective of this review is to highlight the links between different hormones and the immune response mediated by B cells in the etiopathogenesis of systemic lupus erythematosus (SLE), rheumatoid arthritis (RA), and multiple sclerosis (MS). The data collected provide insights into the role of hormones in the cellular, molecular and/or epigenetic mechanisms that modulate the B-cell response in health and disease.

Human Bone Marrow Mesenchymal Stem Cells Promote the M2 Phenotype in Macrophages Derived from STEMI Patients.

Acute ST-elevation myocardial infarction (STEMI) leads to myocardial injury or necrosis, and M1 macrophages play an important role in the inflammatory response. Bone marrow mesenchymal stem/stromal cells (BM-MSCs) are capable of modulating macrophage plasticity, principally due to their immunoregulatory capacity. In the present study, we analyzed the capacity of MSCs to modulate macrophages derived from monocytes from patients with STEMI. We analyzed the circulating levels of cytokines associated with M1 and M2 macrophages in patients with STEMI, and the levels of cytokines associated with M1 macrophages were significantly higher in patients with STEMI than in controls. BM-MSCs facilitate the generation of M1 and M2 macrophages. M1 macrophages cocultured with MSCs did not have decreased M1 marker expression, but these macrophages had an increased expression of markers of the M2 macrophage phenotype (CD14, CD163 and CD206) and IL-10 and IL-1Ra signaling-induced regulatory T cells (Tregs). M2 macrophages from patients with STEMI had an increased expression of M2 phenotypic markers in coculture with BM-MSCs, as well as an increased secretion of anti-inflammatory cytokines and an increased generation of Tregs. The findings in this study indicate that BM-MSCs have the ability to modulate the M1 macrophage response, which could improve cardiac tissue damage in patients with STEMI.

Mesenchymal Stem/Stromal Cells Derived from Cervical Cancer Promote M2 Macrophage Polarization.

Macrophages with the M2 phenotype promote tumor development through the immunosuppression of antitumor immunity. We previously demonstrated the presence of mesenchymal stem/stromal cells (MSCs) in cervical cancer (CeCa-MSCs), suggesting an immune protective capacity in tumors, but to date, their effect in modulating macrophage polarization remains unknown. In this study, we compared the capacities of MSCs from normal cervix (NCx) and CeCa to promote M2 macrophage polarization in a coculture system. Our results demonstrated that CeCa-MSCs, in contrast to NCx-MSCs, significantly decreased M1 macrophage cell surface marker expression (HLA-DR, CD80, CD86) and increased M2 macrophage expression (CD14, CD163, CD206, Arg1) in cytokine-induced CD14+ monocytes toward M1- or M2-polarized macrophages. Interestingly, compared with NCx-MSCs, in M2 macrophages generated from CeCa-MSC cocultures, we observed an increase in the percentage of phagocytic cells, in the intracellular production of IL-10 and IDO, the capacity to decrease T cell proliferation and for the generation of CD4+CD25+FoxP3+ Tregs. Importantly, this capacity to promote M2 macrophage polarization was correlated with the intracellular expression of macrophage colony-stimulating factor (M-CSF) and upregulation of IL-10 in CeCa-MSCs. Furthermore, the presence of M2 macrophages was correlated with the increased production of IL-10 and IL-1RA anti-inflammatory molecules. Our in vitro results indicate that CeCa-MSCs, in contrast to NCx-MSCs, display an increased M2-macrophage polarization potential and suggest a role of CeCa-MSCs in antitumor immunity.

Prolactin promotes proliferation of germinal center B cells, formation of plasma cells, and elevated levels of IgG3 anti-dsDNA autoantibodies.

Systemic lupus erythematosus (SLE) mainly affects females at reproductive age, which has been associated with hormones, such as prolactin (PRL). Different studies suggest that PRL exacerbates the clinical manifestations of SLE both in patients and in mouse models (e.g., the MRL/lpr strain), increasing the production of autoantibodies, which can be deposited as immune complexes and trigger inflammation and damage to different tissues. The objective of this work was to explore the potential mechanisms by which PRL increases the concentration of self-reactive antibodies in the MRL/lpr SLE model. To this end, we determined the role of PRL on the activation and proliferation of germinal center B cells (B-GCs) and their differentiation into antibody-secreting cells (ASCs). We show that the absolute number and percentage of B-GCs were significantly increased by PRL in vivo or upon in vitro treatment with anti-IgM and anti-CD40 antibodies and PRL. The augmented B-GC numbers correlated with enhanced proliferation, but we did not observe enhanced expression of CD80 and CD86 activation markers or the BCL6 transcription factor, arguing against a more effective differentiation. Nevertheless, we observed enhanced phosphorylation of STAT1, secretion of IL-6, expression of IRF4, numbers of ASCs, and levels of IgG3 antibodies directed against dsDNA. Altogether, these results support the hypothesis that a PRL-mediated expansion of B-GCs yields more self-reactive ASCs, potentially explaining the pathogenic immune complexes that steadily lead to tissue damage during SLE.

The effect of prolactin on immune cell subsets involved in SLE pathogenesis.

The higher frequency of autoimmune diseases in the female population compared to males suggests that certain hormones, such as prolactin (PRL), play a role in determining the prevalence of autoimmunity in women, particularly during childbearing age. PRL can act not only as a hormone but also as a cytokine, being able to modulate immune responses. Hyperprolactinemia has been implicated in the pathogenesis of various autoimmune diseases where it may affect disease activity. One of the conditions where PRL has such a role is systemic lupus erythematosus (SLE). PRL regulates the proliferation and survival of both lymphoid and myeloid cells. It also affects the selection of T-cell repertoires by influencing the thymic microenvironment. In autoimmune conditions, PRL interferes with the activity of regulatory T cells. It also influences B cell tolerance by lowering the activation threshold of anergic B cells. The production of CD40L and cytokines, such as interleukin IL-6, are also promoted by PRL. This, in turn, leads to the production of autoantibodies, one of the hallmarks of SLE. PRL increases the cytotoxic activity of T lymphocytes and the secretion of proinflammatory cytokines. The production of proinflammatory cytokines, particularly those belonging to the type 1 interferon (IFN) family, is part of the SLE characteristic genetic signature. PRL also participates in the maturation and differentiation of dendritic cells, promoting the presentation of autoantigens and high IFNα secretion. It also affects neutrophil function and the production of neutrophil traps. Macrophages and dendritic cells can also be affected by PRL, linking this molecule to the abnormal behavior of both innate and adaptive immune responses.This review aimed to highlight the importance of PRL and its actions on the cells of innate and adaptive immune responses. Additionally, by elucidating the role of PRL in SLE etiopathogenesis, this work will contribute to a better understanding of the factors involved in SLE development and regulation.

Prolactin Increases the Frequency of Follicular T Helper Cells with Enhanced IL21 Secretion and OX40 Expression in Lupus-Prone MRL/lpr Mice.

Systemic lupus erythematosus is characterized by high levels of IgG class autoantibodies that contribute to the pathophysiology of the disease. The formation of these autoantibodies occurs in the germinal centers, where there is cooperation between follicular T helper cells (TFH) and autoreactive B cells. Prolactin has been reported to exacerbate the clinical manifestations of lupus by increasing autoantibody concentrations. The objective of this study was to characterize the participation of prolactin in the differentiation and activation of TFH cells, by performing in vivo and in vitro tests with lupus-prone mice, using flow cytometry and real-time PCR. We found that TFH cells express the long isoform of the prolactin receptor and promoted STAT3 phosphorylation. Receptor expression was higher in MRL/lpr mice and correlative with the manifestations of the disease. Although prolactin does not intervene in the differentiation of TFH cells, it does favor their activation by increasing the percentage of TFH OX40+ and TFH IL21+ cells, as well as leading to high serum concentrations of IL21. These results support a mechanism in which prolactin participates in the emergence of lupus by inducing overactive TFH cells and perhaps promoting dysfunctional germinal centers.

Efficacy of Docosahexaenoic Acid for the Prevention of Necrotizing Enterocolitis in Preterm Infants: A Randomized Clinical Trial.

Necrotizing enterocolitis (NEC) is an inflammatory bowel disease and a leading cause of morbidity and mortality in preterm infants. In this study, a randomized double-blind parallel-group (1:1) trial was carried out in two neonatal intensive care units of two tertiary hospitals. Two hundred and twenty-five preterm newborns with an expected functional gastrointestinal tract were recruited and received an enteral dose of 75 mg of docosahexaenoic acid (DHA)/kg body weight or high-oleic sunflower oil daily for 14 days from the first enteral feed after birth. Confirmed NEC was evaluated with Bell's scale from stage ≥ IIa. Two hundred and fourteen randomized infants were analyzed in terms of the intent-to-treat (DHA-group: n = 105; control-group: n = 109); data for two hundred infants were analysed per protocol. Confirmed NEC was lower in infants from the DHA-group compared with the control-group (0/100 vs. 7/100; p = 0.007), with RR = 0.93 (95% CI 0.881 to 0.981), risk difference = -7%, (95% CI -12.00 to -1.99), and number needed-to-treat = 15 (95% CI 8.3 to 50). Intent-to-treat analysis showed a lower level of treatment failure in the DHA-group compared with the control-group (6/105 (6%) vs. 16/109 (15%); p = 0.03, RR = 0.905, (95% CI 0.826 to 0.991)). The results after multivariate-regression analysis remained significant. Adverse events (apart from the incidence of NEC) were not different between groups. A daily dose of DHA for 14 days starting with the first enteral feed may prevent NEC in preterm infants.

Prolactin Rescues Immature B Cells from Apoptosis-Induced BCR-Aggregation through STAT3, Bcl2a1a, Bcl2l2, and Birc5 in Lupus-Prone MRL/lpr Mice.

Self-reactive immature B cells are eliminated through apoptosis by tolerance mechanisms, failing to eliminate these cells results in autoimmune diseases. Prolactin is known to rescue immature B cells from B cell receptor engagement-induced apoptosis in lupus-prone mice. The objective of this study was to characterize in vitro prolactin signaling in immature B cells, using sorting, PCR array, RT-PCR, flow cytometry, and chromatin immunoprecipitation. We found that all B cell maturation stages in bone marrow express the prolactin receptor long isoform, in both wild-type and MRL/lpr mice, but its expression increased only in the immature B cells of the latter, particularly at the onset of lupus. In these cells, activation of the prolactin receptor promoted STAT3 phosphorylation and upregulation of the antiapoptotic Bcl2a1a, Bcl2l2, and Birc5 genes. STAT3 binding to the promoter region of these genes was confirmed through chromatin immunoprecipitation. Furthermore, inhibitors of prolactin signaling and STAT3 activation abolished the prolactin rescue of self-engaged MRL/lpr immature B cells. These results support a mechanism in which prolactin participates in the emergence of lupus through the rescue of self-reactive immature B cell clones from central tolerance clonal deletion through the activation of STAT3 and transcriptional regulation of a complex network of genes related to apoptosis resistance.

Effect of Interleukin-17 in the Activation of Monocyte Subsets in Patients with ST-Segment Elevation Myocardial Infarction.

Interleukin- (IL-) 17 is increased in acute myocardial infarction (AMI) and plays a key role in inflammatory diseases through its involvement in the activation of leukocytes. Here, we describe for the first time the effect of IL-17 in the migration and activation of monocyte subsets in patients during ST-segment elevation myocardial infarction (STEMI) and post-STEMI. We analyzed the circulating levels of IL-17 in patient plasma. A gradual increase in IL-17 was found in STEMI and post-STEMI patients. Additionally, IL-17 had a powerful effect on the recruitment of CD14++CD16+/CD14+CD16++ monocytes derived from patients post-STEMI compared with the monocytes from patients with STEMI, suggesting that IL-17 recruits monocytes with inflammatory activity post-STEMI. Furthermore, IL-17 increased the expression of TLR4 on CD14 + CD16 - and CD14++CD16+/CD14+CD16++ monocytes post-STEMI and might enhance the response to danger-associated molecular patterns post-STEMI. Moreover, IL-17 induced secretion of IL-6 from CD14++CD16- and CD14++CD16+/CD14+CD16++ monocytes both in STEMI and in post-STEMI, which indicates that IL-17 has an effect on the secretion of proinflammatory cytokines from monocytes during STEMI and post-STEMI. Overall, we demonstrate that in STEMI and post-STEMI, IL-17 is increased and induces the migration and activation of monocyte subsets, possibly contributing to the inflammatory response through TLR4 and IL-6 secretion.

IL-17-differentiated macrophages secrete pro-inflammatory cytokines in response to oxidized low-density lipoprotein.

BACKGROUND: Cytokines and macrophages play a central role in the development of atherosclerosis. Interleukin (IL)-17 is a pro-inflammatory cytokine with differential effects on innate immune cells. We investigated the effects of IL-17 on macrophage differentiation and foam cell formation and activation in response to oxidized low-density lipoprotein (oxLDL). METHODS: Human monocytes were treated with IL-17 to induce macrophage differentiation. As controls, human monocytes were differentiated into M1 macrophages (M1) or M2 macrophages (M2). Subsequently, we analyzed the expression levels of markers such as CD80, CD36 and Toll-like receptors (TLRs) as well as foam cell formation and cytokines in M1, M2 and macrophages differentiated with IL-17 with or without oxLDL. RESULTS: The expression of M1 or M2 markers or cytokines was not induced in macrophages differentiated with IL-17. Macrophages differentiated with IL-17 formed few foam cells, with an average proportion of 20%, and expressed 3 times as much TLR2 and 3.8 times as much TLR4 as M0 macrophages. Additionally, macrophages differentiated with IL-17 acquired inflammatory capacity in response to oxLDL through the expression of specific markers, such as CD80, which increased 18-times compared with macrophages differentiated with IL-17 alone, and secreted 1.3 times less tumor necrosis factor (TNF)-α than M1. Additionally, oxLDL increased the levels of CD80, CD86 and IL-6 by 5.7, 2.8 and 1.4 times in M1 compared with M1 in the absence of oxLDL. In M2, oxLDL induced increases in the secretion of IL-6 and TNF-α that were 1.9 times and 1.2 times smaller, respectively, than those observed in M1. CONCLUSION: Our study demonstrates that differentiation of macrophages with IL-17 does not induce the expression of markers or cytokines characteristic of M1 or M2 and these macrophages form few foam cells; however, the expression of TLR is increased. Moreover, these macrophages acquire the inflammatory capacity as evidenced by the expression of costimulatory molecules and secretion of pro-inflammatory cytokines in response to oxLDL. These findings suggest that the activation of macrophages differentiated with IL-17 by oxLDL contributes to the inflammatory process of atherosclerosis.

Enteral Docosahexaenoic Acid Reduces Analgesic Administration in Neonates Undergoing Cardiovascular Surgery.

BACKGROUND: Neonates undergoing surgery require analgesic medication to ameliorate acute pain. These medications produce negative side effects. Docosahexaenoic acid (DHA) has an antinociceptive effect in animals, but this has not been evaluated in human neonates. We evaluated the DHA effect on cumulative dose and duration of analgesics administered to neonates undergoing cardiovascular surgery. METHODS: A secondary analysis was performed with data from a clinical trial, in which enteral DHA was administered perioperatively compared with sunflower oil (SO). Present study assessed the antinociceptive effect of DHA by measuring the cumulative dose and duration of analgesics administered during postoperative stay in a neonatal intensive care unit. Multivariate linear regression models were performed. RESULTS: Seventeen neonates received DHA and 18 received SO in the control group. Compared with the control group, the DHA group received lower cumulative dose (14.6 ± 2.2 vs. 25.2 ± 4.8 µg/kg, p = 0.029) and shorter duration of buprenorphine (2 days (1-8) vs. 4.5 days (1-12); p = 0.053). After adjusting for confounders, the DHA group received significantly lesser buprenorphine (ß = -27 µg/kg, p = 0.028; R2 model = 0.90) for shorter duration (ß = -9 days, p = 0.003; R2 model = 0.94). No differences in fentanyl or ketorolac were detected. CONCLUSIONS: Buprenorphine administration was reduced in neonates who received DHA, suggesting that DHA likely has analgesic effects.

Monocyte Differentiation towards Protumor Activity Does Not Correlate with M1 or M2 Phenotypes.

Macrophages facilitate breast cancer progression. Macrophages were initially classified as M1 or M2 based on their distinct metabolic programs and then expanded to include antitumoral (M1) and protumoral (M2) activities. However, it is still uncertain what markers define the pro- and antitumoral phenotypes and what conditions lead to their formation. In this study, monocytic cell lines and primary monocytes were subjected to commonly reported protocols of M1/M2 polarization and conditions known to engage monocytes into protumoral functions. The results showed that only IDO enzyme and CD86 M1 markers were upregulated correlating with M1 polarization. TNF-α, CCR7, IL-10, arginase I, CD36, and CD163 were expressed indistinguishably from M1 or M2 polarization. Similarly, protumoral engaging resulted in upregulation of both M1 and M2 markers, with conditioned media from the most aggressive breast cancer cell line promoting the greatest changes. In spite of the mixed phenotype, M1-polarized macrophages exhibited the highest expression/secretion of inflammatory mediators, many of which have previously been associated with breast cancer aggressiveness. These data argue that although the existence of protumoral macrophages is unquestionable, their associated phenotypes and the precise conditions driving their formation are still unclear, and those conditions may need both M1 and M2 stimuli.

Prolactin Rescues Immature B-Cells from Apoptosis Induced by B-Cell Receptor Cross-Linking.

Prolactin has an immunomodulatory effect and has been associated with B-cell-triggered autoimmune diseases, such as systemic lupus erythematosus (SLE). In mice that develop SLE, the PRL receptor is expressed in early bone marrow B-cells, and increased levels of PRL hasten disease manifestations, which are correlated with a reduction in the absolute number of immature B-cells. The aim of this work was to determine the effect of PRL in an in vitro system of B-cell tolerance using WEHI-231 cells and immature B-cells from lupus prone MRL/lpr mice. WEHI-231 cells express the long isoform of the PRL receptor, and PRL rescued the cells from cell death by decreasing the apoptosis induced by the cross-linking of the B-cell antigen receptor (BCR) as measured by Annexin V and active caspase-3. This decrease in apoptosis may have been due to the PRL and receptor interaction, which increased the relative expression of antiapoptotic Bcl-xL and decreased the relative expression of proapoptotic Bad. In immature B-cells from MRL/lpr mice, PRL increased the viability and decreased the apoptosis induced by the cross-linking of BCR, which may favor the maturation of self-reactive B-cells and contribute to the onset of disease.

The Morphofunctional Effect of the Transplantation of Bone Marrow Stromal Cells and Predegenerated Peripheral Nerve in Chronic Paraplegic Rat Model via Spinal Cord Transection.

Functional recovery following spinal cord injury (SCI) is limited by poor axonal and cellular regeneration as well as the failure to replace damaged myelin. Employed separately, both the transplantation of the predegenerated peripheral nerve (PPN) and the transplantation of bone marrow stromal cells (BMSCs) have been shown to promote the regrowth and remyelination of the damaged central axons in SCI models of hemisection, transection, and contusion injury. With the aim to test the effects of the combined transplantation of PPN and BMSC on regrowth, remyelination, and locomotor function in an adult rat model of spinal cord (SC) transection, 39 Fischer 344 rats underwent SC transection at T9 level. Four weeks later they were randomly assigned to traumatic spinal cord injury (TSCI) without treatment, TSCI + Fibrin Glue (FG), TSCI + FG + PPN, and TSCI + FG + PPN + BMSCs. Eight weeks after, transplantation was carried out on immunofluorescence and electron microscope studies. The results showed greater axonal regrowth and remyelination in experimental groups TSCI + FG + PPN and TSCI + FG + PPN + BMSCs analyzed with GAP-43, neuritin, and myelin basic protein. It is concluded that the combined treatment of PPN and BMSCs is a favorable strategy for axonal regrowth and remyelination in a chronic SC transection model.

The role of TLR2, TLR4 and CD36 in macrophage activation and foam cell formation in response to oxLDL in humans.

UNLABELLED: Toll-like receptor (TLR)2, TLR4 and CD36 are central in inflammation and the development of atherosclerosis. Oxidized low-density lipoprotein (oxLDL) plays a critical role in this disease through its involvement in the formation of foam cells and the activation of leukocytes. The aim of this research was to analyze the role of TLR2, TLR4 and CD36 in foam cell differentiation and macrophage activation. METHODS: Human macrophages were incubated with monoclonal antibodies specific for TLR2, TLR4 and CD36 prior to stimulation with oxLDL. Subsequently, we analyzed foam cell formation, cytokine secretion, histocompatibility complex (MHC) class II molecules and CD86 expression and T cell proliferation. RESULTS: The stimulation of macrophages with oxLDL induced foam cell formation, cytokine secretion, HLA-DR and CD86 expression and T cell proliferation. The blockage of TLR2, TLR4 and CD36 reduced the secretion of IL-1ß, IL-6 and IL-8, the expression of HLA-DR and CD86, T cell proliferation and foam cell formation. However, the blockage of TLR2 did not affect the formation of foam cells. CONCLUSION: Our study demonstrates that TLR2, TLR4 and CD36 participate in the immune response to oxLDL by inducing an increase in pro-inflammatory cytokines, the expression HLA-DR and CD86 and the proliferation of T cells. However, TLR2 does not participate in the formation of foam cells, while TLR4 and CD36 play a relevant role in this process. These findings suggest that the activation of these receptors by oxLDL contributes to the pathogenesis of atherosclerosis.

Innate immune system cells in atherosclerosis.

Atherosclerosis is a chronic inflammatory disease of the arterial wall characterized by innate and adaptive immune system involvement. A key component of atherosclerotic plaque inflammation is the persistence of different innate immune cell types including mast cells, neutrophils, natural killer cells, monocytes, macrophages and dendritic cells. Several endogenous signals such as oxidized low-density lipoproteins, and exogenous signals such as lipopolysaccharides, trigger the activation of these cells. In particular, these signals orchestrate the early and late inflammatory responses through the secretion of pro-inflammatory cytokines and contribute to plaque evolution through the formation of foam cells, among other events. In this review we discuss how innate immune system cells affect atherosclerosis pathogenesis.

Prolactin levels correlate with abnormal B cell maturation in MRL and MRL/lpr mouse models of systemic lupus erythematosus-like disease.

Prolactin (PRL) plays an important role in modulating the immune response. In B cells, PRL enhances antibody production, including antibodies with self-specificity. In this study, our aims were to determine the level of PRL receptor expression during bone-marrow B-cell development and to assess whether the presence of high PRL serum concentrations influences absolute numbers of developing populations and disease outcome in lupus-prone murine models. We observed that the PRL-receptor is expressed in early bone-marrow B-cell; the expression in lupus-prone mice, which had the highest level of expression in pro-B cells and immature cells, differed from that in wild-type mice. These expression levels did not significantly change in response to hyperprolactinemia; however, populations of pro-B and immature cells from lupus-prone strains showed a decrease in the absolute numbers of cells with high PRL-receptor expression in response to PRL. Because immature self-reactive B cells are constantly being eliminated, we assessed the expression of survival factor BIRC5, which is more highly expressed in both pro-B and immature B-cells in response to PRL and correlates with the onset of disease. These results identify an important role of PRL in the early stages of the B-cell maturation process: PRL may promote the survival of self-reactive clones.

Participación de la prolactina en la respuesta inmune / Role of prolactin in the immune response

Existen evidencias de la relación entre el sistema inmune y el endocrino vía múltiples factores de comunicación, como citocinas, neuropéptidos, neurotransmisores y hormonas. Se ha demostrado la participación de la hormona prolactina en la respuesta inmune innata y adaptativa. Además de ser producida por la glándula pituitaria, también es producida y secretada por las células del sistema inmunológico. El objetivo de esta revisión fue puntualizar acerca de la participación de la prolactina secretada por estas células en la respuesta inmune.

Evidence exists about the relationship between the immune and the endocrine systems through communication of multiple factors such as cytokines, neuropeptides, neurotransmitters and hormones. Among the hormones, prolactin (PRL) has been shown to participate in the innate and adaptive immune response. In addition to being produced by the pituitary gland, PRL is also produced and secreted by cells of the immune system. The aim of this review is to update information about the involvement of PRL secreted by immune system cells in the immune response.

Increased levels of prolactin receptor expression correlate with the early onset of lupus symptoms and increased numbers of transitional-1 B cells after prolactin treatment.

BACKGROUND: Prolactin is secreted from the pituitary gland and other organs, as well as by cells such as lymphocytes. Prolactin has an immunostimulatory effect and is associated with autoimmune diseases that are characterised by abnormal B cell activation, such as systemic lupus erythematosus (SLE). Our aim was to determine if different splenic B cell subsets express the prolactin receptor and if the presence of prolactin influences these B cell subsets and correlates with development of lupus. RESULTS: Using real-time PCR and flow cytometry, we found that different subsets of immature (transitional) and mature (follicular, marginal zone) B cells express different levels of the prolactin receptor and are differentially affected by hyperprolactinaemia. We found that transitional B cells express the prolactin receptor at higher levels compared to mature B cells in C57BL/6 mice and the lupus-prone MRL/lpr and MRL mouse strains. Transitional-1 (T1) B cells showed a higher level of prolactin receptor expression in both MRL/lpr and MRL mice compared to C57BL/6 mice. Hyperprolactinaemia was induced using metoclopramide, which resulted in the development of early symptoms of SLE. We found that T1 B cells are the main targets of prolactin and that prolactin augments the absolute number of T1 B cells, which reflects the finding that this B cell subpopulation expresses the highest level of the prolactin receptor. CONCLUSIONS: We found that all B cell subsets express the prolactin receptor but that transitional B cells showed the highest prolactin receptor expression levels. Hyperprolactinaemia in mice susceptible to lupus accelerated the disease and increased the absolute numbers of T1 and T3 B cells but not of mature B cells, suggesting a primary effect of prolactin on the early stages of B cell maturation in the spleen and a role of prolactin in B cell differentiation, contributing to SLE onset.

Intranasal anti-rabies DNA immunization promotes a Th1-related cytokine stimulation associated with plasmid survival time.

BACKGROUND AND AIMS: DNA vaccination has a great potential to decrease infectious diseases worldwide, such as rabies. Here we showed the effects of a single anti-rabies DNA vaccination applied intranasally (IN) on plasmid survival time, neutralizing antibody (NA) titers, G-protein expression and Th1/Th2-related cytokines. METHODS: Only one 50-µg dose of an anti-rabies DNA vaccine was IN administered to 160 Balb/c mice. Twenty mice were used for the neutralizing antibody study, 35 for the proliferation assay, 35 for Th1/Th2-related cytokines, 35 for glycoprotein expression by immunocytochemistry, and 35 for pGQH detection and G-protein mRNA expression. RESULTS: Th1-type related cytokines from spleen cells (IFN-γ, TNF-α, and IL-2) were detected. Rabies NA titers were ≥0.6 IUs from day 30 onward in the IN DNA-vaccinated group. The plasmid was identified in brains and lungs from days 3-15. The mRNA transcript was amplified in brains and lungs from days 3-30, and G-protein expression was observed in spleens, brains and lungs on days 3, 8, and 15. In all cases, a gradual decrease was observed on days 30 and 45 and absent on day 60. CONCLUSIONS: We found that Th1-type related cytokines (IL-2, IFN-γ, and TNF-α) were stimulated during the first month after DNA vaccination, correlating with the proliferation assays. Also, it was associated with the plasmid survival time remaining in lungs and brains prior to its degradation.