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Objective: To characterize the immune functionality and phenotype and the proviral composition of a cohort of young adults with perinatally-acquired HIV (p-YA) from Argentina., Design: Cross-sectional study of 18 p-YA, 15 young adults with non-perinatally acquired HIV matched by age with p-YA and 14 adults with non-perinatally acquired HIV, matched by time from HIV diagnosis with p-YA, all from Argentina., Methods: Immune memory/effector phenotype, exhaustion, activation, PTK-7 and Ki-67 expression were evaluated by flow cytometry on NK and T-cells. Total, intact and defective proviral (TP, IP and DP) HIV-DNA were measured in CD4 T-cells by IPDA. Soluble markers were determined by ELISA., Results: p-YA displayed lower expression of PD-1, higher levels of CD38 + CD4 T-cells and increased levels of naïve T-cells than control groups. Also, a trend of lower levels of IP HIV-DNA normalized to CD4 T-cell counts and to the proportion of naïve T-cells was found in p-YA., Conclusion: The higher frequency of naïve CD4 T-cells in p-YA cannot be explained by elevated thymic activity nor by a higher T-cell proliferation rate. This imbalance could have been generated early in life and persisted during adulthood. Naïve CD4 T-cells may not serve as a major viral reservoir in p-YA. Also, the lower PD-1 + CD4 T-cell count suggests that p-YA did not present higher levels of exhaustion. These findings suggest that acquiring HIV perinatally may imply different challenges for proviral eradication., (Copyright © 2024 Wolters Kluwer Health, Inc. All rights reserved.)

The experimental versatility of the fruit fly has helped to uncover the molecular basis of epithelial cell polarity. In this chapter, we provide protocols to dissect Drosophila larval salivary glands (SGs) for ex vivo culture and live imaging, and for fixing and immunostaining for analysis by fluorescence microscopy. We describe how to combine these approaches with genetic and pharmacological assays. These techniques can be applied to study signaling pathways regulating epithelial cell polarity, membrane trafficking, gland secretion, and their impacts on animal feeding behavior., (© 2022. Springer Science+Business Media, LLC, part of Springer Nature.)

Background: Most children and youth develop mild or asymptomatic disease during severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. However, a very small number of patients suffer severe Coronavirus induced disease 2019 (COVID-19). The reasons underlying these different outcomes remain unknown., Methods: We analyzed three different cohorts: children with acute infection (n=550), convalescent children (n=138), and MIS-C (multisystem inflammatory syndrome in children, n=42). IgG and IgM antibodies to the spike protein of SARS-CoV-2, serum-neutralizing activity, plasma cytokine levels, and the frequency of circulating Follicular T helper cells (cTfh) and plasmablasts were analyzed by conventional methods., Findings: Fifty-eight percent of the children in the acute phase of infection had no detectable antibodies at the time of sampling while a seronegative status was found in 25% and 12% of convalescent and MIS-C children, respectively. When children in the acute phase of the infection were stratified according disease severity, we found that contrasting with the response of children with asymptomatic, mild and moderate disease, children with severe COVID-19 did not develop any detectable response. A defective antibody response was also observed in the convalescent cohort for children with severe disease at the time of admission. This poor antibody response was associated to both, a low frequency of cTfh and a high plasma concentration of inflammatory cytokines., Interpretation: A weak and delayed kinetic of antibody response to SARS-CoV-2 together with a systemic pro-inflammatory profile characterize pediatric severe COVID-19. Because comorbidities are highly prevalent in children with severe COVID-19, further studies are needed to clarify their contribution in the weak antibody response observed in severe disease., Funding: National Agency for Scientific and Technological Promotion from Argentina (IP-COVID-19-0277 and PMO-BID-PICT2018-2548)., Competing Interests: Declaration of Competing Interest None., (Copyright © 2021 The Author(s). Published by Elsevier B.V. All rights reserved.)

Background: Perhaps reflecting that children with COVID-19 rarely exhibit severe respiratory symptoms and often remain asymptomatic, little attention has been paid to explore the immune response in pediatric COVID-19. Here, we analyzed the phenotype and function of circulating neutrophils from children with COVID-19., Methods: An observational study including 182 children with COVID-19, 21 children with multisystem inflammatory syndrome (MIS-C), and 40 healthy children was performed in Buenos Aires, Argentina. Neutrophil phenotype was analyzed by flow cytometry in blood samples. Cytokine production, plasma levels of IgG antibodies directed to the spike protein of SARS-CoV-2 and citrullinated histone H3 were measured by ELISA. Cell-free DNA was quantified by fluorometry., Findings: Compared with healthy controls, neutrophils from children with COVID-19 showed a lower expression of CD11b, CD66b, and L-selectin but a higher expression of the activation markers HLA-DR, CD64 and PECAM-1 and the inhibitory receptors LAIR-1 and PD-L1. No differences in the production of cytokines and NETs were observed. Interestingly, the expression of CD64 in neutrophils and the serum concentration of IgG antibodies directed to the spike protein of SARS-CoV-2 distinguished asymptomatic from mild and moderate COVID-19., Interpretation: Acute lung injury is a prominent feature of severe COVID-19 in adults. A low expression of adhesion molecules together with a high expression of inhibitory receptors in neutrophils from children with COVID-19 might prevent tissue infiltration by neutrophils preserving lung function., Funding: This study was supported by the Ministry of Science and Technology (National Agency for Scientific and Technological Promotion, IP-COVID-19-0277 and PMO BID PICT 2018-2548), and University of Buenos Aires from Argentina (20020170100573BA)., Competing Interests: Declaration of Competing Interest The authors have declared that no conflict of interest exists., (Copyright © 2021 The Authors. Published by Elsevier B.V. All rights reserved.)

An efficient vectorial intracellular transport machinery depends on a well-established apico-basal polarity and is a prerequisite for the function of secretory epithelia. Despite extensive knowledge on individual trafficking pathways, little is known about the mechanisms coordinating their temporal and spatial regulation. Here, we report that the polarity protein Crumbs is essential for apical plasma membrane phospholipid-homeostasis and efficient apical secretion. Through recruiting β Heavy -Spectrin and MyosinV to the apical membrane, Crumbs maintains the Rab6-, Rab11- and Rab30-dependent trafficking and regulates the lipid phosphatases Pten and Ocrl. Crumbs knock-down results in increased apical levels of PI(4,5)P 2 and formation of a novel, Moesin- and PI(4,5)P 2 -enriched apical membrane sac containing microvilli-like structures. Our results identify Crumbs as an essential hub required to maintain the organization of the apical membrane and the physiological activity of the larval salivary gland., Competing Interests: JL, WL, MB, DF No competing interests declared, EK Reviewing editor, eLife, (© 2019, Lattner et al.)

The organization of intracellular transport processes is adapted specifically to different cell types, developmental stages, and physiologic requirements. Some protein traffic routes are universal to all cells and constitutively active, while other routes are cell-type specific, transient, and induced under particular conditions only. Small GTPases of the Rab (Ras related in brain) subfamily are conserved across eukaryotes and regulate most intracellular transit pathways. The complete sets of Rab proteins have been identified in model organisms, and molecular principles underlying Rab functions have been uncovered. Rabs provide intracellular landmarks that define intracellular transport sequences. Nevertheless, it remains a challenge to systematically map the subcellular distribution of all Rabs and their functional interrelations. This task requires novel tools to precisely describe and manipulate the Rab machinery in vivo. Here we discuss recent findings about Rab roles during development and we consider novel approaches to investigate Rab functions in vivo.

We report a case of chagasic meningoencephalitis reactivation in a pregnant woman co-infected with Trypanosoma cruzi and HIV that was successfully managed with benznidazole and highly active antiretroviral therapy. Early diagnosis enabled rapid specific treatment that improved the health of the patient and her baby.