Lymphoid Organs Research Articles

In BTK, phosphorylated Y223 in the SH3 domain mirrors catalytic activity, but does not influence biological function

AbstractBruton’s tyrosine kinase (BTK) is an enzyme needed for B-cell survival, and its inhibitors have become potent targeted medicines for the treatment of B-cell malignancies. The initial activation event of cytoplasmic protein-tyrosine kinases is the phosphorylation of a conserved regulatory tyrosine in the catalytic domain, which in BTK is represented by tyrosine 551. In addition, the tyrosine 223 (Y223) residue in the SRC homology 3 (SH3) domain has, for more than 2 decades, generally been considered necessary for full enzymatic activity. The initial recognition of its potential importance stems from transformation assays using nonlymphoid cells. To determine the biological significance of this residue, we generated CRISPR-Cas–mediated knockin mice carrying a tyrosine to phenylalanine substitution (Y223F), maintaining aromaticity and bulkiness while prohibiting phosphorylation. Using a battery of assays to study leukocyte subsets and the morphology of lymphoid organs, as well as the humoral immune responses, we were unable to detect any difference between wild-type mice and the Y223F mutant. Mice resistant to irreversible BTK inhibitors, through a cysteine 481 to serine substitution (C481S), served as an additional immunization control and mounted similar humoral immune responses as Y223F and wild-type animals. Collectively, our findings suggest that phosphorylation of Y223 serves as a useful proxy for phosphorylation of phospholipase Cγ2 (PLCG2), the endogenous substrate of BTK. However, in contrast to a frequently held conception, this posttranslational modification is dispensable for the function of BTK.

Optimizing protocols for monitoring in vivo replication of a novel chimeric Marek’s disease vaccine with an insertion of the long terminal repeat of reticuloendotheliosis virus in the CVI988 strain genome (CVI-LTR)

ABSTRACT Monitoring Marek’s disease (MD) vaccination is routinely done by evaluating the load of MD vaccine in the feather pulp (FP) between 7 and 10 days of age. However, attempts in our laboratory to detect a novel CVI-LTR vaccine in the FP samples from commercial flocks failed. The objective of this study was to evaluate the most suitable tissue and age to monitor CVI-LTR vaccination. We used two different commercial CVI988 vaccines as controls. One hundred and sixty 1-day-old commercial brown layers were vaccinated with either CVI-LTR, CVI988-A, CVI988-B or remained unvaccinated. Samples of the spleen, thymus, and bursa were collected at 3, 4, 5, and 6 days of age and samples of FP were collected at 7 and 21 days for DNA isolation. Our results showed that CVI-LTR replicated earlier than CVI988 vaccines in the lymphoid organs but was not detected in the FP at either 7 or at 21 days of age. We also confirmed that either the spleen or thymus collected at 4–6 days was a suitable sample to monitor CVI-LTR vaccination in commercial flocks. Finally, we evaluated the load of oncogenic MDV DNA in five commercial flocks that were vaccinated with either CVI-LTR + rHVT or CVI988-A + rHVT. The load of oncogenic MDV DNA was evaluated at 21 days in the FP in 20 chickens per group. Our results demonstrated that CVI-LTR was more successful in reducing oncogenic MDV DNA at 21 days of age than the CVI988-A strain. RESEARCH HIGHLIGHTS CVI-LTR replicates in the thymus and spleen earlier than CVI988. CVI-LTR replicates in lymphoid organs but it cannot be detected in feather pulp. CVI-LTR reduced the load of oncogenic MDV DNA more efficiently than CVI988.

Disruption of IL-17-mediated immunosurveillance in the respiratory mucosa results in invasive Streptococcus pyogenes infection.

Streptococcus pyogenes is a Gram-positive pathogen that causes a significant global burden of skin pyoderma and pharyngitis. In some cases, infection can lead to severe invasive streptococcal diseases. Previous studies have shown that IL-17 deficiency in mice (IL-17-/-) can reduce S. pyogenes clearance from the mucosal surfaces. However, the effect of IL-17 on the development of severe invasive streptococcal disease has not yet been assessed. Here, we modeled single or repeated non-lethal intranasal (IN) S. pyogenes M1 strain infections in immunocompetent and IL-17-/- mice to assess bacterial colonization following a final IN or skin challenge. Immunocompetent mice that received a single S. pyogenes infection showed long-lasting immunity to subsequent IN infection, and no bacteria were detected in the lymph nodes or spleens. However, in the absence of IL-17, a single IN infection resulted in dissemination of S. pyogenes to the lymphoid organs, which was accentuated by repeated IN infections. In contrast to what was observed in the respiratory mucosa, skin immunity did not correlate with the systemic levels of IL-17. Instead, it was found to be associated with the activation of germinal center responses and accumulation of neutrophils in the spleen. Our results demonstrated that IL-17 plays a critical role in preventing invasive disease following S. pyogenes infection of the respiratory tract.

Cancer immunity by tissue-resident type 1 innate lymphoid cells and killer innate-like T cells.

Cancer progression can be restrained by tumor-infiltrating lymphocytes in a process termed cancer immunosurveillance. Based on how lymphocytes are activated and recruited to the tumor tissue, cancer immunity is either pre-wired, in which innate lymphocytes and innate-like T cells are directly recruited to and activated in tumors following their differentiation in primary lymphoid organs; or priming-dependent, in which conventional adaptive T cells are first primed by cognate antigens in secondary lymphoid organs before homing to and reactivated in tumors. While priming-dependent cancer immunity has been a focus of cancer immunology research for decades, in part due to historical preconception of cancer theory and tumor model choice as well as clinical success of conventional adaptive T cell-directed therapeutic programs, recent studies have revealed that pre-wired cancer immunity mediated by tissue-resident type 1 innate lymphoid cells (ILC1s) and killer innate-like T cells (ILTCKs) is an integral component of the cancer immunosurveillance process. Herein we review the distinct ontogenies and cancer-sensing mechanisms of ILC1s and ILTCKs in murine genetic cancer models as well as the conspicuously conserved responses in human malignancies. How ILC1s and ILTCKs may be targeted to broaden the scope of cancer immunotherapy beyond conventional adaptive T cells is also discussed.

RelA-mediated signaling connects adaptation to chronic cardiomyocyte stress with myocardial and systemic inflammation in the ADCY8 model of accelerated aging.

Mice with cardiac-specific overexpression of adenylyl cyclase (AC) type 8 (TGAC8) are under a constant state of severe myocardial stress. They have a remarkable ability to adapt to this stress, but they eventually develop accelerated cardiac aging and experience reduced longevity. We have previously demonstrated through bioinformatics that constitutive adenylyl cyclase activation in TGAC8 mice is associated with the activation of inflammation-related signaling pathways. However, the immune response associated with chronic myocardial stress in the TGAC8 mouse remains unexplored. Here we demonstrate that chronic activation of adenylyl cyclase in cardiomyocytes of TGAC8 mice results inactivation of cell-autonomous RelA-mediated NF-κB signaling. This is associated with non-cell-autonomous activation of proinflammatory and age-associated signaling in myocardial endothelial cells and myocardial smooth muscle cells, expansion of myocardial immune cells, increase in serum levels of inflammatory cytokines, and changes in the size or composition of lymphoid organs. All these changes precede the appearance of cardiac fibrosis. We provide evidence indicating that RelA activation in cardiomyocytes with chronic activation of adenylyl cyclase is mediated by calcium-protein Kinase A (PKA) signaling. Using a model of chronic cardiomyocyte stress and accelerated aging, we highlight a novel, calcium/PKA/RelA-dependent connection between cardiomyocyte stress, myocardial inflammation, and systemic inflammation. These findings suggest that RelA-mediated signaling in cardiomyocytes might be an adaptive response to stress that, when chronically activated, ultimately contributes to bothcardiac and systemic aging.

Single-cell RNA sequencing unveils the hidden powers of zebrafish kidney for generating both hematopoiesis and adaptive antiviral immunity

The vertebrate kidneys play two evolutionary conserved roles in waste excretion and osmoregulation. Besides, the kidney of fish is considered as a functional ortholog of mammalian bone marrow that serves as a hematopoietic hub for generating blood cell lineages and immunological responses. However, knowledge about the properties of kidney hematopoietic cells, and the functionality of the kidney in fish immune systems remains to be elucidated. To this end, our present study generated a comprehensive atlas with 59 hematopoietic stem/progenitor cell (HSPC) and immune-cells types from zebrafish kidneys via single-cell transcriptome profiling analysis. These populations included almost all known cells associated with innate and adaptive immunity, and displayed differential responses to viral infection, indicating their diverse functional roles in antiviral immunity. Remarkably, HSPCs were found to have extensive reactivities to viral infection, and the trained immunity can be effectively induced in certain HSPCs. In addition, the antigen-stimulated adaptive immunity can be fully generated in the kidney, suggesting the kidney acts as a secondary lymphoid organ. These results indicated that the fish kidney is a dual-functional entity with functionalities of both primary and secondary lymphoid organs. Our findings illustrated the unique features of fish immune systems, and highlighted the multifaced biology of kidneys in ancient vertebrates.

Single-cell RNA sequencing unveils the hidden powers of zebrafish kidney for generating both hematopoiesis and adaptive antiviral immunity.

The vertebrate kidneys play two evolutionary conserved roles in waste excretion and osmoregulation. Besides, the kidney of fish is considered as a functional ortholog of mammalian bone marrow that serves as a hematopoietic hub for generating blood cell lineages and immunological responses. However, knowledge about the properties of kidney hematopoietic cells, and the functionality of the kidney in fish immune systems remains to be elucidated. To this end, our present study generated a comprehensive atlas with 59 hematopoietic stem/progenitor cell (HSPC) and immune-cells types from zebrafish kidneys via single-cell transcriptome profiling analysis. These populations included almost all known cells associated with innate and adaptive immunity, and displayed differential responses to viral infection, indicating their diverse functional roles in antiviral immunity. Remarkably, HSPCs were found to have extensive reactivities to viral infection, and the trained immunity can be effectively induced in certain HSPCs. In addition, the antigen-stimulated adaptive immunity can be fully generated in the kidney, suggesting the kidney acts as a secondary lymphoid organ. These results indicated that the fish kidney is a dual-functional entity with functionalities of both primary and secondary lymphoid organs. Our findings illustrated the unique features of fish immune systems, and highlighted the multifaced biology of kidneys in ancient vertebrates.

Clinicopathological characteristics and predictors of outcome of rapidly progressive glomerulonephritis: a retrospective study.

Globally, there are regional and time-based variations in the prevalence, etiology, and prognosis of rapidly progressive glomerulonephritis (RPGN). Prognosis of RPGN is poor, with a higher risk of death and end stage renal disease (ESRD) even with immunosuppressive medications. In the Middle East and North Africa, the studies on this disease are very limited. Therefore, we determined the predictors of outcome of RPGN. We retrospectively assessed 101 adult patients over age of 18, diagnosed with RPGN based on renal biopsy illustrating crescents in ≥ 50% of the glomeruli. Patients who had crescents in their renal biopsies that were < 50% and those who refused to consent to a renal biopsy were excluded. We categorized the patients into 3 groups based on immunohistochemistry; type I, type II and type III. Then, depending on renal loss, we divided them into ESRD and non-ESRD groups. The clinical history and physical examination were retrieved. Additionally, 24-hour urine protein, urine analysis, renal function tests, serum albumin, complete blood count, antinuclear antibodies, anti-double stranded DNA antibodies, ANCA antibodies and serum complement levels were checked. Each patient underwent a kidney biopsy for immunohistochemistry and light microscopy. The percentage of crescentic glomeruli, number of sclerosed glomeruli, tertiary lymphoid organ (TLO), neutrophil infiltration, endocapillary or mesangial hypercellularity, interstitial fibrosis with tubular atrophy (IFTA) were analyzed. Primary outcomes (remission, ESRD and mortality) and secondary outcomes were assessed. Type II was the most frequent cause of RPGN (47.5%), followed by type III (32.7%) and type I (19.8%). 32 patients (31.7%) died during follow up, whereas 60 patients (59.4%) developed ESRD. In 41 patients (40.6%), remission occurred. Oliguria, serum creatinine, and need for HD at presentation were significantly increased in ESRD group compared to non-ESRD group (P < 0.001 for each). Mesangial proliferation, IFTA, TLO formation, sclerotic glomeruli and fibrous crescents were also significantly increased in ESRD group in comparison to non-ESRD group (P < 0.001 for each). Glomerulosclerosis (P = 0.036), and IFTA (P = 0.008) were predictors of ESRD. Infections (P = 0.02), respiratory failure (P < 0.001), and heart failure (P = 0.004) were mortality risk factors. Type II RPGN was the most common. Infection was the most frequent secondary outcome. Oliguria, glomerulosclerosis, the requirement for hemodialysis at presentation, IFTA and TLO formation were predictors of ESRD. Respiratory failure, heart failure and infections were significant predictors of mortality.

A distinct "repair" role of regulatory T cells in fracture healing.

Regulatory T cells (Tregs) suppress immune responses and inflammation. Here, we described the distinct nonimmunological role of Tregs in fracture healing. The recruitment from the circulation pool, peripheral induction, and local expansion rapidly enriched Tregs in the injured bone. The Tregs in the injured bone displayed superiority in direct osteogenesis over Tregs from lymphoid organs. Punctual depletion of Tregs compromised the fracture healing process, which leads to increased bone nonunion. In addition, bone callus Tregs showed unique T-cell receptor repertoires. Amphiregulin was the most overexpressed protein in bone callus Tregs, and it can directly facilitate the proliferation and differentiation of osteogenic precursor cells by activation of phosphatidylinositol 3-kinase/protein kinase B signaling pathways. The results of loss- and gain-function studies further evidenced that amphiregulin can reverse the compromised healing caused by Treg dysfunction. Tregs also enriched in patient bone callus and amphiregulin can promote the osteogenesis of human pre-osteoblastic cells. Our findings indicate the distinct and nonredundant role of Tregs in fracture healing, which will provide a new therapeutic target and strategy in the clinical treatment of fractures.

Lymph-targeted high-density lipoprotein-mimetic nanovaccine for multi-antigenic personalized cancer immunotherapy.

Cancer vaccines show huge potential for cancer prevention and treatment. However, their efficacy remains limited due to weak immunogenicity regarding inefficient stimulation of cytotoxic T lymphocyte (CTL) responses. Inspired by the unique characteristic and biological function of high-density lipoprotein (HDL), we here develop an HDL-mimicking nanovaccine with the commendable lymph-targeted capacity to potently elicit antitumor immunity using lipid nanoparticle that is co-loaded with specific cancer cytomembrane harboring a collection of tumor-associated antigens and an immune adjuvant. The nanoparticulate impact is explored on the efficiency of lymphatic targeting and dendritic cell uptake. The optimized nanovaccine promotes the co-delivery of antigens and adjuvants to lymph nodes and maintains antigen presentation of dendritic cells, resulting in long-term immune surveillance as the elevated frequency of CTLs within lymphoid organs and tumor tissue. Immunization of nanovaccine suppresses tumor formation and growth and augments the therapeutic efficacy of checkpoint inhibitors notably on the high-stemness melanoma in the mouse models.

Antibody-independent protection against heterologous SARS-CoV-2 challenge conferred by prior infection or vaccination.

Vaccines have reduced severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) morbidity and mortality, yet emerging variants challenge their effectiveness. The prevailing approach to updating vaccines targets the antibody response, operating under the presumption that it is the primary defense mechanism following vaccination or infection. This perspective, however, can overlook the role of T cells, particularly when antibody levels are low or absent. Here we show, through studies in mouse models lacking antibodies but maintaining functional B cells and lymphoid organs, that immunity conferred by prior infection or mRNA vaccination can protect against SARS-CoV-2 challenge independently of antibodies. Our findings, using three distinct models inclusive of a novel human/mouse ACE2 hybrid, highlight that CD8+ T cells are essential for combating severe infections, whereas CD4+ T cells contribute to managing milder cases, with interferon-γ having an important function in this antibody-independent defense. These findings highlight the importance of T cell responses in vaccine development, urging a broader perspective on protective immunity beyond just antibodies.

B-cells in pulmonary arterial hypertension: friend, foe or bystander?

There is an unmet need for new therapeutic strategies that target alternative pathways to improve the prognosis of patients with pulmonary arterial hypertension (PAH). As immunity has been involved in the development and progression of vascular lesions in PAH, we review the potential contribution of B-cells in its pathogenesis and evaluate the relevance of B-cell-targeted therapies. Circulating B-cell homeostasis is altered in PAH patients, with total B-cell lymphopenia, abnormal subset distribution (expansion of naïve and antibody-secreting cells, reduction of memory B-cells) and chronic activation. B-cells are recruited to the lungs through local chemokine secretion, and activated by several mechanisms: 1) interaction with lung vascular autoantigens through cognate B-cell receptors; 2) costimulatory signals provided by T follicular helper cells (interleukin (IL)-21), type 2 T helper cells and mast cells (IL-4, IL-6 and IL-13); and 3) increased survival signals provided by B-cell activating factor pathways. This activity results in the formation of germinal centres within perivascular tertiary lymphoid organs and in the local production of pathogenic autoantibodies that target the pulmonary vasculature and vascular stabilisation factors (including angiotensin-II/endothelin-1 receptors and bone morphogenetic protein receptors). B-cells also mediate their effects through enhanced production of pro-inflammatory cytokines, reduced anti-inflammatory properties by regulatory B-cells, immunoglobulin (Ig)G-induced complement activation, and IgE-induced mast cell activation. Precision-medicine approaches targeting B-cell immunity are a promising direction for select PAH conditions, as suggested by the efficacy of anti-CD20 therapy in experimental models and a trial of rituximab in systemic sclerosis-associated PAH.

Intra-abdominal transplantation of PLGA/PCL/M13 phage electrospun scaffold induces self-assembly of lymphoid tissue-like structure

Lymphoid organs are the main structural components of the immune system. In the current research, the mixture of poly lactic-co-glycolic acid (PLGA), polycaprolactone (PCL), and M13 phage or its RGD-modified form was used in the construction of a fibrillar scaffold using the electrospinning method. The constructs were transplanted intra-abdominally and examined for the formation of lymphoid-like tissues at different time intervals. The confocal and scanning electron microscopy demonstrate that M13 phage-containing scaffolds provide a suitable environment for lymph node-isolated fibroblasts. Morphological analysis demonstrate the formation of lymph node-like tissues in the M13 phage-containing scaffolds after transplantation. Histological analysis confirm both blood and lymph angiogenesis in the implanted construct and migration of inflammatory cells to the M13 phage-containing scaffolds. In addition, flow cytometry and immunohistochemistry analysis showed the homing and compartmentalization of dendritic cells (DCs), B and T lymphocytes within the PLGA/PCL/M13 phage-RGD based scaffolds and similar to what is seen in the mouse lymphoid tissues. It seems that the application of M13 phage could improve the generation of functional lymphoid tissues in the electrospun scaffolds and could be used for lymphoid tissue regeneration.

Improving Anti-HIV activity and pharmacokinetics of enfuvirtide (T20) by modification with oligomannose

Dendritic cells (DCs) play a pivotal role in controlling HIV-1 infections of CD4+ T cells. DC-SIGN, which is expressed on the surface of DCs, efficiently captures HIV-1 virions by binding to the highly mannosylated membrane protein, gp120, and then the DCs transport the virus to target T cells in lymphoid organs. This study explored the modification of T20, a peptide inhibitor of HIV-1 fusion, by conjugation of the N-terminus with varying sizes of oligomannose, which are DC-SIGN-specific carbohydrates, aiming to create dual-targeting HIV inhibitors. Mechanistic studies indicated the dual-target binding of the conjugates. Antiviral assays demonstrated that N-terminal mannosylation of T20 resulted in increased inhibition of the viral infection of TZM-b1 cells (EC50 = 0.3−0.8 vs. 1.4 nM). Pentamannosylated T20 (M5-T20) exhibited a stronger inhibitory effect on virus entry into DC-SIGN+ 293T cells compared with T20 (67% vs. 50% inhibition at 500 μM). M5-T20 displayed an extended half-life in rats relative to T20 (T1/2: 8.56 vs. 1.64 h, respectively). These conjugates represent a potential new treatment for HIV infections with improved antiviral activity and pharmacokinetics, and this strategy may prove useful in developing dual-target inhibitors for other pathogens that require DC-SIGN involvement for infection.

RNA-seq analysis of chlorogenic acid intervention in duck embryo fibroblasts infected with duck plague virus

IntroductionChlorogenic acid, the primary active component in Chinese medicines like honeysuckle, exhibits anti-inflammatory and antiviral effects. It has been demonstrated that chlorogenic acid effectively prevents and treats Duck enteritis virus (DEV) infection. This study aims to further elucidate the mechanism by which chlorogenic acid prevents DEV infection.MethodsDuck embryo fibroblast (DEF) cells were pre-treated with chlorogenic acid before being infected with DEV. Cell samples were collected at different time points for transcriptomic sequencing, while qPCR was used to detect the proliferation of DEV. Additionally, 30-day-old ducks were treated with chlorogenic acid, and their lymphoid organs were harvested for histopathological sections to observe pathological damage. The proliferation of DEV in the lymphoid organs was also detected using qPCR Based on the transcriptomic sequencing results, NF-κB1 gene was silenced by RNAi technology to analyze the effect of NF-κB1 gene on DEV proliferation.ResultsCompared to the viral infection group, DEF cells in the chlorogenic acid intervention group exhibited significantly reduced DEV load (P < 0.05). Transcriptomic sequencing results suggested that chlorogenic acid inhibited DEV proliferation in DEF cells by regulating NF-κB signaling pathway. The results of RNAi silencing suggested that in the three treatment groups, compared with the DEV experimental group, there was no significant difference in the effect of pre-transfection after transfection on DEV proliferation, while both the pre-transfection after transfection and the simultaneous transfection group showed significant inhibition on DEV proliferation Furthermore, compared to the virus infection group, ducks in the chlorogenic acid intervention group showed significantly decreased DEV load in their lymphoid organs (P < 0.05), along with alleviated pathological damage such as nuclear pyretosis and nuclear fragmentation.ConclusionsChlorogenic acid effectively inhibits DEV proliferation in DEF and duck lymphatic organs, mitigates viral-induced pathological damage, and provides a theoretical basis for screening targeted drugs against DEV.

Effects of low-dose rapamycin on lymphoid organs of mice prone and resistant to accelerated senescence.

Aging is a complex, natural, and irreversible phenomenon that subjects the body to numerous changes in the physiological process, characterized by a gradual decline in the organism's homeostatic mechanisms, closely related to immunosenescence. Here, we evaluated the regulation of immunosenescence in lymphoid organs of senescence-accelerated prone 8 (SAM-P8) and senescence-accelerated resistant 1 (SAM-R1) mice treated with a low dose of rapamycin (RAPA). Mice were treated with a dose of 7.1 µg/kg RAPA for 2 months and had body mass and hematological parameters analyzed prior and during treatment. Cellular and humoral parameters of serum, bone marrow, thymus, and spleen samples were evaluated by ELISA, histology, and flow cytometry. Changes in body mass, hematological parameters, cell number, and in the secretion of IL-1β, IL-6, TNF-α, IL-7, and IL-15 cytokines were different between the 2 models used. In histological analyses, we observed that SAM-P8 mice showed faster thymic involution than SAM-R1 mice. Regarding the T lymphocyte subpopulations in the spleen, CD4+ and CD8+ T cell numbers were higher and lower, respectively, in SAM-P8 mice treated with RAPA, with the opposite observed in SAM-R1. Additionally, we found that the low dose of RAPA used did not trigger changes that could compromise the immune response of these mice and the administered dose may have contributed to changes in important lymphocyte populations in the adaptive immune response and the secretion of cytokines that directly collaborate with the maturation and proliferation of these cells.

Generation of a virus-like particles based vaccine against IgE.

Anti-IgE immunotherapy with monoclonal antibodies represents a breakthrough in treatment of severe allergic diseases. However, drawbacks such as short half-life and high price are not negligible. Our objective is to develop an anti-IgE vaccine based on virus-like particles (VLPs) which can induce long-lasting neutralizing IgG anti-IgE antibodies reducing allergic responses without causing intrinsic mast cell activation due to IgE cross-linking. The vaccines were made by chemically coupling three synthetic mouse IgE-Fc fragments to plant-derived immunologically optimized CuMVTT VLPs. The immunogenicity of the vaccines was tested by immunizing naive or allergic mice either with the coupled vaccines or the VLP control followed by systemic or local allergen challenge. Mice immunized with the vaccines exhibited high titers of anti-IgE antibodies in the sera and high levels of anti-IgE secreting plasma cells in lymphoid organs. Moreover, free IgE in serum were reduced by the induced anti-IgE antibodies; therefore, less IgE was bound to FcεRI on the surface of basophils. In line with these reduced IgE levels on effector cells after vaccination, immunized mice were protected from challenge with allergens. Importantly, despite presence of anti-IgE antibodies, no signs of acute or chronic allergic response were seen in immunized allergic mice. The generated vaccines can effectively induce anti-IgE antibodies that did not cause allergic responses in sensitized mice but were able to decrease the level of free and cell bound IgE and protected sensitized animals from allergic responses upon allergen challenge.

Gene expression analyses reveal differences in children’s response to malaria according to their age

In Bandiagara, Mali, children experience on average two clinical malaria episodes per year. However, even in the same transmission area, the number of uncomplicated symptomatic infections, and their parasitemia, can vary dramatically among children. We simultaneously characterize host and parasite gene expression profiles from 136 Malian children with symptomatic falciparum malaria and examine differences in the relative proportion of immune cells and parasite stages, as well as in gene expression, associated with infection and or patient characteristics. Parasitemia explains much of the variation in host and parasite gene expression, and infections with higher parasitemia display proportionally more neutrophils and fewer T cells, suggesting parasitemia-dependent neutrophil recruitment and/or T cell extravasation to secondary lymphoid organs. The child’s age also strongly correlates with variations in gene expression: Plasmodium falciparum genes associated with age suggest that older children carry more male gametocytes, while variations in host gene expression indicate a stronger innate response in younger children and stronger adaptive response in older children. These analyses highlight the variability in host responses and parasite regulation during P. falciparum symptomatic infections and emphasize the importance of considering the children’s age when studying and treating malaria infections.

Pathological Characterization and Risk Factors of Splenic Nodular Lesions in Dogs (Canis lupus familiaris).

In dogs, the spleen is a secondary lymphoid organ that can be affected by both neoplastic and non-neoplastic nodules. In general, few studies relate histopathological diagnosis to tumor size and the number of nodules in spleen biopsies. Some of these studies are inconclusive regarding the difference between neoplastic and non-neoplastic lesions and have small sample sizes or do not consider all splenic lesions. This study aimed to characterize splenic masses and determine risk factors for spleen tumors in dogs. A total of 507 histological reports corresponding to the diagnosis of splenic lesions in dogs from a private laboratory of animal pathology in the Metropolitan Region, Chile, were used. Data were analyzed by descriptive statistics and multiple logistic regression. The most frequent neoplastic and non-neoplastic diagnoses were hemangiosarcoma and hyperplasia, respectively. Most of the cases occurred in male (265 cases, 52.3%), senior (421 cases, 83%), and purebred individuals (342 cases, 67.5%). The most affected breeds were the Cocker Spaniel, German Shepherd, and Labrador Retriever. The most frequent lesion was a single nodule. The variables that exhibited a greater risk for the presentation of splenic neoplasia were male sex (odds ratio (OR) = 16.21; 95% confidence interval (CI) 1.741-150.879; p = 0.014), the presence of two or more splenic nodules (OR = 3.94; 95% CI 2.168-7.177; p < 0.001), an increase in nodule size greater than 2 cm (OR for quartiles 2, 3 and 4 of 2.2; 95% CI 1.036-4.941; p = 0.041, 2.9; 95% CI 1.331-6.576; p = 0.008, and 3.6; 95% CI 1.562-8.499; p = 0.003, respectively), and increasing age (OR = 1.23; 95% CI 1.048-1.436; p = 0.011). On the other hand, males exhibited a lower risk as age increases (OR = 0.76; 95% CI 0.615-0.928; p = 0.008). In conclusion, this study identified that males, multinodular presentation, nodule size, and age are risk factors for the occurrence of splenic neoplasia in dogs, knowledge that will contribute to the diagnostic management of dogs with spleen lesions.

Lipid nanoparticle structure and delivery route during pregnancy dictate mRNA potency, immunogenicity, and maternal and fetal outcomes

Treating pregnancy-related disorders is exceptionally challenging because the threat of maternal and/or fetal toxicity discourages the use of existing medications and hinders new drug development. One potential solution is the use of lipid nanoparticle (LNP) RNA therapies, given their proven efficacy, tolerability, and lack of fetal accumulation. Here, we describe LNPs for efficacious mRNA delivery to maternal organs in pregnant mice via several routes of administration. In the placenta, our lead LNP transfected trophoblasts, endothelial cells, and immune cells, with efficacy being structurally dependent on the ionizable lipid polyamine headgroup. Next, we show that LNP-induced maternal inflammatory responses affect mRNA expression in the maternal compartment and hinder neonatal development. Specifically, pro-inflammatory LNP structures and routes of administration curtailed efficacy in maternal lymphoid organs in an IL-1β-dependent manner. Further, immunogenic LNPs provoked the infiltration of adaptive immune cells into the placenta and restricted pup growth after birth. Together, our results provide mechanism-based structural guidance on the design of potent LNPs for safe use during pregnancy.