Generation of Cytotoxic T Cells and Dysfunctional CD8 T Cells in Severe COVID-19 Patients.

COVID-19, the infectious disease caused by SARS-CoV-2, has spread on a pandemic scale. The viral infection can evolve asymptomatically or can generate severe symptoms, influenced by the presence of comorbidities. Lymphopenia based on the severity of symptoms in patients affected with COVID-19 is frequent.

Dysfunctional purinergic signaling correlates with disease severity in COVID-19 patients.

Ectonucleotidases modulate inflammatory responses by balancing extracellular ATP and adenosine (ADO) and might be involved in COVID-19 immunopathogenesis. Here, we explored the contribution of extracellular nucleotide metabolism to COVID-19 severity in mild and severe cases of the disease. We verified that the gene expression of ectonucleotidases is reduced in the whole blood of patients with COVID-19 and is negatively correlated to levels of CRP, an inflammatory marker of disease severity.

SARS-CoV-2 and Other Respiratory Viruses: What Does Oxidative Stress Have to Do with It?

The phenomenon of oxidative stress, characterized as an imbalance in the production of reactive oxygen species and antioxidant responses, is a well-known inflammatory mechanism and constitutes an important cellular process. The relationship of viral infections, reactive species production, oxidative stress, and the antiviral response is relevant. Therefore, the aim of this review is to report studies showing how reactive oxygen species may positively or negatively affect the pathophysiology of viral infection.

Frequencies of CD33+CD11b+HLA-DR-CD14-CD66b+ and CD33+CD11b+HLA-DR-CD14+CD66b- Cells in Peripheral Blood as Severity Immune Biomarkers in COVID-19.

Common clinical features of patients with Coronavirus disease-2019 (COVID-19) vary from fever, to acute severe respiratory distress syndrome. Several laboratory parameters are reported as indicators of COVID-19 severity. We hereby describe the possible novel severity biomarkers for COVID-19, CD11b+CD33+HLA-DR-CD14+ cells and CD11b+CD33+HLA-DR-CD66b+ cells.

Case Report: COVID-19 and Chagas Disease in Two Coinfected Patients.

American trypanosomiasis, also named Chagas disease (CD), is an anthropozoonosis caused by the protozoan parasite . The disease affects millions of people worldwide, leading yearly to approximately 50,000 deaths. COVID-19, generated by SARS-CoV-2, can lead to lymphopenia and death.

Association between the timing of maternal vaccination and newborns' anti-pertussis toxin antibody levels.

Background: Pertussis remains an important global public health concern, despite the presence of extensive immunization programs. Incidence and severity of pertussis are typically higher in neonates and young infants. As a strategy to protect these young infants, maternal vaccination with Tdap (tetanus toxoid, reduced diphtheria toxoid, and acellular pertussis) has been recommended in Brazil.

The effectiveness of maternal pertussis vaccination in protecting newborn infants in Brazil: A case-control study.

Introduction: In 2014, the Brazilian Ministry of Health (MoH) recommended Tdap to pregnant women in response to a significant increase in the incidence of pertussis among infants. The present study assessed the effectiveness of maternal immunization in preventing pertussis in infants.

Methods: An unmatched case-control study was undertaken in São Paulo State, Brazil from February 2015 to July 2016.

Neonatal Immunity to Infection and Current Prevention Strategies.

is the bacterial agent of whooping cough, an infectious disease that is reemerging despite high vaccine coverage. Newborn children are the most affected, not only because they are too young to be vaccinated but also due to qualitative and quantitative differences in their immune system, which makes them more susceptible to infection and severe manifestations, leading to a higher mortality rate comparing to other groups. Until recently, prevention consisted of vaccinating children in the first year of life and the herd vaccination of people directly in touch with them, but the increase in cases demands more effective strategies that can overcome the developing immune response in early life and induce protection while children are most vulnerable.

The Relationship between Maternal Plasma Leptin and Adiponectin Concentrations and Newborn Adiposity.

Increased maternal blood concentrations of leptin and decreased adiponectin levels, which are common disturbances in obesity, may be involved in offspring adiposity by programming fetal adipose tissue development. The aim of this study was to assess the relationship between maternal leptin and adiponectin concentrations and newborn adiposity. This was a cross-sectional study involving 210 healthy mother-newborn pairs from a public maternity hospital in São Paulo, Brazil.

Role of nitric oxide in immune responses against viruses: beyond microbicidal activity.

Introduction: Nitric oxide (NO) is a free radical produced during L-arginine metabolism. In addition to its physiological activities in vascular and neuronal functions, its role in the immune system as a microbicide and tumor-killing mediator has been well described, as well as its release by activated macrophages. Furthermore, NO is produced by a variety of immune and non-immune cells and is involved in the regulation of several immune functions, such as T-cell polarization and suppression.

Staphylococcal enterotoxin B induces specific IgG4 and IgE antibody serum levels in atopic dermatitis.

Background: Atopic dermatitis (AD) is a chronic recurrent inflammatory disease, with prevalence of about 10-20% in children and 1-3% in adults. Staphylococcus aureus is present in 80-100% of skin from atopic patients and is related to worsening of the disease by the action of enterotoxins. The aim of this study was to evaluate the profile of anti-Staphylococcus aureus enterotoxin B (SEB) antibody isotypes and IgG subclass levels in adult AD.

Serodiagnosis as adjunct assay for pertussis infection in São Paulo, Brazil.

Pertussis remains an important public health problem in many countries despite extensive immunization. Cultures and real-time PCR (RT-PCR) assays are the recommended pertussis diagnostic tests, but they lack sensitivity at the later stage of the disease. This study introduces the IgG anti-pertussis toxin enzyme-linked immunosorbent assay (PT ELISA) in our routine diagnosis to improve disease burden estimation.

The neonatal immune system: immunomodulation of infections in early life.

The innate and adaptive immune responses in neonates are usually functionally impaired when compared with their adult counterparts. The qualitative and quantitative differences in the neonatal immune response put them at risk for the development of bacterial and viral infections, resulting in increased mortality. Newborns often exhibit decreased production of Th1-polarizing cytokines and are biased toward Th2-type responses.

Mucosal and systemic anti-GAG immunity induced by neonatal immunization with HIV LAMP/gag DNA vaccine in mice.

Vaccines capable of inducing mucosal immunity in early postnatal life until adulthood, protecting early sexual initiation, should be considered as strategies to vaccination against HIV. The HIV-1 GAG protein as a chimera with the lysosome-associated membrane protein (LAMP/gag), encoded by a DNA vaccine, is targeted to the endosomal/lysosomal compartment that contains class II MHC molecules and has been shown to be immunogenic in adult mice. Assuming that one such strategy could help to overcome the immunological immaturity in the early postnatal period, we have evaluated the systemic and mucosal immunogenicity of LAMP/gag immunization in neonatal mice.

Profile of autoantibodies against phosphorylcholine and cross-reactivity to oxidation-specific neoantigens in selective IgA deficiency with or without autoimmune diseases.

Immunoglobulin A deficiency (IgAD) is considered the most common form of primary immunodeficiency. The majority of IgA-deficient individuals are considered asymptomatic, even though IgAD has been associated with an increased frequency of recurrent infections, allergy, and autoimmune diseases. In this study we evaluate the Natural autoantibodies (NatAbs) reactivity to phosphorylcholine (PC) and to some pro-inflammatory molecules in IgAD with or without autoimmune disorders.

Immunization of neonatal mice with LAMP/p55 HIV gag DNA elicits robust immune responses that last to adulthood.

Successful T cell priming in early postnatal life that can generate effective long-lasting responses until adulthood is critical in HIV vaccination strategies because it prevents early sexual initiation and breastfeeding transmission of HIV. A chimeric DNA vaccine encoding p55 HIV gag associated with lysosome-associated membrane protein 1 (LAMP-1; which drives the antigen to the MIIC compartment), has been used to enhance cellular and humoral antigen-specific responses in adult mice and macaques. Herein, we investigated LAMP-1/gag vaccine immunogenicity in the neonatal period in mice and its ability to generate long-lasting effects.

Immune adjuvants in early life: targeting the innate immune system to overcome impaired adaptive response.

The neonatal phase is a transitory period characterized by an absence of memory cells, favoring a slow adaptive response prone to tolerance effects and the development of Th2-type responses. However, when appropriately stimulated, neonates may achieve an immune response comparable with adult counterparts. One strategy to stimulate the immunological response of neonates or children in early infancy has been to explore natural or synthetic ligands of cell receptors to stimulate innate immunity.

Maternal immunization with ovalbumin prevents neonatal allergy development and up-regulates inhibitory receptor Fc gamma RIIB expression on B cells.

Background: Preconception allergen immunization prevents neonatal allergen sensitization in mice by a complex interaction between regulatory cells/factors and antibodies. The present study assessed the influence of maternal immunization with ovalbumin (OVA) on the immune response of 3 day-old and 3 week-old offspring immunized or non-immunized with OVA and evaluated the effect of IgG treatment during fetal development or neonatal period.

Results: Maternal immunization with OVA showed increased levels of Fc gamma RIIb expression in splenic B cells of neonates, which were maintained for up to 3 weeks and not affected by additional postnatal OVA immunization.

CpG-induced Th1-type response in the downmodulation of early development of allergy and inhibition of B7 expression on T cells of newborn mice.

Introduction: Several differences have been described between neonatal and adult immune responses. The predisposition in early life to Th2-type response or tolerance makes it a susceptible period for infections and allergic sensitization.

Objective: The aim of this work was to evaluate the effects of CpG-containing oligodeoxynucleotides on neonatal and adult immunization with ovalbumin and Blomia tropicalis extract and compare the CpG effects on B and T cells of neonatal and adult mice.

Balance between early life tolerance and sensitization in allergy: dependence on the timing and intensity of prenatal and postnatal allergen exposure of the mother.

Allergens can be maternally transferred to the fetus or neonate, though it is uncertain how this initial allergen exposure may impact the development of allergy responses. To evaluate the roles of timing and level of maternal allergen exposure in the early life sensitization of progeny, female BALB/c mice were given ovalbumin (OVA) orally during pregnancy, lactation or weekly at each stage to investigate the immunoglobulin E (IgE) antibody production and cellular responsiveness of their offspring. Exposure to OVA during pregnancy was also evaluated in OVA-specific T-cell receptor (TCR) transgenic (DO11.

Maternal-fetal interaction: preconception immunization in mice prevents neonatal sensitization induced by allergen exposure during pregnancy and breastfeeding.

Allergen exclusion measures during pregnancy and lactation have been given consideration in studies of primary allergy prevention but complete avoidance of mother/neonatal allergen exposure has proven to be a difficult procedure. To evaluate a strategy to prevent allergen sensitization in early life in mice, we first established a neonatal model with ovalbumin sensitization through maternal allergen exposure during pregnancy or breastfeeding. The modulatory potential of preconception immunization was investigated on the neonatal development of subsequent allergic responses to maternal allergen exposure.

Long-term anergy in orally tolerized mice is linked to decreased B7.2 expression on B cells.

Durable antigen (Ag)-specific T- and B-cell anergy induced by oral tolerance is an attractive strategy for immunotherapy of allergic diseases. Here, we address the lasting effect of oral tolerance induction in naïve or primed mice to ovalbumin (OVA) on antibody production. Single feeding with OVA prior to immunization or double feeding, before and after Ag priming, in A/Sn mice, induced a long-lasting suppression of IgE, IgG1 and IgG2a responses up to 8 months after immunization.