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Introduction: Memory CD8+ T cells are essential for long-term immune protection in viral infections, including COVID-19. Methods: This study examined the responses of CD8+ TEM, TEMRA, and TCM subsets from unvaccinated individuals who had recovered from mild and severe COVID-19 by flow cytometry. Results and Discussion: The peptides triggered a higher frequency of CD8+ TCM cells in the recovered mild group. CD8+ TCM and TEM cells showed heterogeneity in CD137 expression between evaluated groups. In addition, a predominance of CD137 expression in naïve CD8+ T cells, TCM, and TEM was observed in the mild recovered group when stimulated with peptides. Furthermore, CD8+ TCM and TEM cell subsets from mild recovered volunteers had higher TNF-α expression. In contrast, the expression partner of IFN-γ, IL-10, and IL-17 indicated an antiviral signature by CD8+ TEMRA cells. These findings underscore the distinct functional capabilities of each memory T cell subset in individuals who have recovered from COVID-19 upon re-exposure to SARS-CoV-2 antigens. [ABSTRACT FROM AUTHOR]

Leishmaniasis belongs to a complex of zoonotic disease caused by protozoa of the genus Leishmania and is considered a major public health problem. Several essential oil chemical components have inhibitory effect against protozoa, including Leishmania donovani. Thus, the aim of this study was to evaluate for the first time the anti-Leishmania activity of two p-menthane monoterpene isomers (EPER-1: perillaldehyde 1,2-epoxide and EPER-2: perillaldehyde 8,9-epoxide) against L. donovani promastigotes as well as evaluating cytotoxic effect on mononuclear peripheral blood cells. Results of anti-Leishmania assay revealed that EPER-2 (IC50 = 3.8 μg.mL−1) was 16-fold more potent than its isomer EPER-1 (IC50 = 64.6 μg.mL−1). In contrast to PBMC cells, EPER-2 was not cytotoxic (IC50 > 400 μg.mL−1) when compared to positive control. These data suggest that the disposition of epoxide group into the p-menthane skeleton affects the anti-Leishmania activity, being that the presence of the exocyclic epoxide group considerably increased potency. Thus, it was possible to observe that the location of the epoxide group into the p-menthane skeleton resulted in different potencies. [ABSTRACT FROM AUTHOR]

Introduction: Memory CD8 + T cells are essential for long-term immune protection in viral infections, including COVID-19., Methods: This study examined the responses of CD8 + TEM, TEMRA, and TCM subsets from unvaccinated individuals who had recovered from mild and severe COVID-19 by flow cytometry., Results and Discussion: The peptides triggered a higher frequency of CD8 + TCM cells in the recovered mild group. CD8 + TCM and TEM cells showed heterogeneity in CD137 expression between evaluated groups. In addition, a predominance of CD137 expression in naïve CD8 + T cells, TCM, and TEM was observed in the mild recovered group when stimulated with peptides. Furthermore, CD8 + TCM and TEM cell subsets from mild recovered volunteers had higher TNF-α expression. In contrast, the expression partner of IFN-γ, IL-10, and IL-17 indicated an antiviral signature by CD8 + TEMRA cells. These findings underscore the distinct functional capabilities of each memory T cell subset in individuals who have recovered from COVID-19 upon re-exposure to SARS-CoV-2 antigens.

Leishmaniasis is a group of neglected, vector-borne infectious diseases that affect millions of people around the world. The medications available for its treatment, especially in cases of visceral leishmaniasis, are old, outdated and have serious side effects. In this work, 10 chalcones were synthesised and evaluated in vitro against promastigotes and axenic amastigotes of Leishmania infantum . Compounds CP04 and CP06 were the most promising, respectively presenting IC 50 values = 13.64 ± 0.25 and 11.19 ± 0.22 µM against promastigotes, and IC 50 = 18.92 ± 0.05 and 22.42 ± 0.05 µM against axenic amastigotes. Only compound CP04 did not show cytotoxicity against peripheral blood mononuclear cells (PBMCs). Molecular docking studies conducted with sterol 14-alpha demethylase (CYP-51) (PDB: 3L4D) and trypanothione reductase (PDB: 5EBK) enzymes from L. infantum evidenced the great affinity of compound CP04 for these targets, presenting Moldock score values of -94.0758 and -50.5692 KJ/mol -1 .

Leishmaniasis represents a series of severe neglected tropical diseases caused by protozoa of the genus Leishmania and is widely distributed around the world. Here, we present the syntheses of Morita-Baylis-Hillman adducts (MBHAs) prepared from eugenol, thymol and carvacrol, and their bioevaluation against promastigotes of Leishmania amazonensis . The new MBHAs are prepared in two steps from essential oils in moderate to good yields and present IC 50 values in the range of 22.30-4.71 μM. Moreover, the selectivity index to the most potent compound is very high (SIrb > 84.92), far better than that of Glucantime ® (SIrb 1.39) and amphotericin B (SIrb = 22.34). Conformational analysis were carried out at the M062X//6-31+G(d,p) level of theory to corroborate a hypothesis about the nitroaromatic bioreduction mechanism.

Carcinoma of the uterine cervix is the second most common female tumor worldwide, surpassed only by breast cancer. Natural products from seaweeds evidencing apoptotic activity have attracted a great deal of attention as new leads for alternative and complementary preventive or therapeutic anticancer agents. Here, methanol extracts from 13 species of tropical seaweeds (Rhodophytas, Phaeophyta and Chlorophyta) collected from the Northeast of Brazil were assessed as apoptosis-inducing agents on human cervical adenocarcinoma (HeLa). All extracts showed different levels of cytotoxicity against HeLa cells; the most potent were obtained from the brown alga Dictyota cilliolata (MEDC) and Dictyota menstrualis (MEDM). In addition, MEDC and MEDM also inhibits SiHa (cervix carcinoma) cell proliferation. Studies with these two extracts using flow cytometry and fluorescence microscopy showed that HeLa cells exposed to MEDM and MEDC exhibit morphological and biochemical changes that characterize apoptosis as shown by loss of cell viability, chromatin condensation, phosphatidylserine externalization, and sub-G1 cell cycle phase accumulation, also MEDC induces cell cycle arrest in cell cycle phase S. Moreover, the activation of caspases 3 and 9 by these extracts suggests a mitochondria-dependent apoptosis route. However, other routes cannot be ruled out. Together, these results point out the methanol extracts of the brown algae D. mentrualis and D. cilliolata as potential sources of molecules with antitumor activity.