Expression of TIGIT, PD-1 and HLA-DR/CD38 markers on CD8-T cells of children and adolescents infected with HIV and uninfected controls.

Immune exhaustion and senescence are scarcely studied in HIV-pediatric patients. We studied the circulatory CD8 T cells activation/exhaustion and senescent phenotype of children and adolescents vertically infected with HIV or uninfected controls based on the expression of human leukocyte antigen (HLA-DR), CD38, T cell immunoglobulin and immunoreceptor tyrosine-based inhibitory motif (ITIM) domain (TIGIT), programmed death 1 (PD-1) and CD57 by flow cytometry, during approximately one year. Eleven HIV-infected (HI) and nine HIV-uninfected (HU) children/adolescents who received two doses or one dose of meningococcal C conjugate vaccine (MenC), respectively, were involved in this study. Blood samples were collected before the immunization (T0), 1-2 months after the first dose (T1), and 1-2 months after the second dose (T2), which was administered approximately one year after the first one. HI patients not receiving combined antiretroviral therapy (cART) showed a higher frequency of CD8 T cells TIGIT+, PD-1+ or CD57+, as well as a higher frequency of CD8 T cells co-expressing CD38/HLA-DR/TIGIT or CD38/HLA-DR/PD-1 when compared to HI treated or HU individuals, at all times that they were assessed. CD8 T cells co-expressing CD38/DR/TIGIT were inversely correlated with the CD4/CD8 ratio but positively associated with viral load. The co-expression of CD38/DR/TIGIT or CD38/DR/PD-1 on CD8 T cells was also inversely associated with the CD4 T cells expressing co-stimulatory molecules CD127/CD28. The results showed a higher expression of exhaustion/senescence markers on CD8 T cells of untreated HI children/adolescents and its correlations with viral load.

Expression of TIGIT, PD-1 and HLA-DR/CD38 markers on CD8-T cells of children and adolescents infected with HIV and uninfected controls

ABSTRACT Immune exhaustion and senescence are scarcely studied in HIV-pediatric patients. We studied the circulatory CD8 T cells activation/exhaustion and senescent phenotype of children and adolescents vertically infected with HIV or uninfected controls based on the expression of human leukocyte antigen (HLA-DR), CD38, T cell immunoglobulin and immunoreceptor tyrosine-based inhibitory motif (ITIM) domain (TIGIT), programmed death 1 (PD-1) and CD57 by flow cytometry, during approximately one year. Eleven HIV-infected (HI) and nine HIV-uninfected (HU) children/adolescents who received two doses or one dose of meningococcal C conjugate vaccine (MenC), respectively, were involved in this study. Blood samples were collected before the immunization (T0), 1-2 months after the first dose (T1), and 1-2 months after the second dose (T2), which was administered approximately one year after the first one. HI patients not receiving combined antiretroviral therapy (cART) showed a higher frequency of CD8 T cells TIGIT+, PD-1+ or CD57+, as well as a higher frequency of CD8 T cells co-expressing CD38/HLA-DR/TIGIT or CD38/HLA-DR/PD-1 when compared to HI treated or HU individuals, at all times that they were assessed. CD8 T cells co-expressing CD38/DR/TIGIT were inversely correlated with the CD4/CD8 ratio but positively associated with viral load. The co-expression of CD38/DR/TIGIT or CD38/DR/PD-1 on CD8 T cells was also inversely associated with the CD4 T cells expressing co-stimulatory molecules CD127/CD28. The results showed a higher expression of exhaustion/senescence markers on CD8 T cells of untreated HI children/adolescents and its correlations with viral load.

CD4/CD8 Ratio and KT Ratio Predict Yellow Fever Vaccine Immunogenicity in HIV-Infected Patients.

BACKGROUND: HIV-infected individuals have deficient responses to Yellow Fever vaccine (YFV) and may be at higher risk for adverse events (AE). Chronic immune activation-characterized by low CD4/CD8 ratio or high indoleamine 2,3-dioxygenase-1 (IDO) activity-may influence vaccine response in this population. METHODS: We prospectively assessed AE, viremia by the YFV virus and YF-specific neutralizing antibodies (NAb) in HIV-infected (CD4>350) and -uninfected adults through 1 year after vaccination. The effect of HIV status on initial antibody response to YFV was measured during the first 3 months following vaccination, while the effect on persistence of antibody response was measured one year following vaccination. We explored CD4/CD8 ratio, IDO activity (plasma kynurenine/tryptophan [KT] ratio) and viremia by Human Pegivirus as potential predictors of NAb response to YFV among HIV-infected participants with linear mixed models. RESULTS: 12 HIV-infected and 45-uninfected participants were included in the final analysis. HIV was not significantly associated with AE, YFV viremia or NAb titers through the first 3 months following vaccination. However, HIV-infected participants had 0.32 times the NAb titers observed for HIV-uninfected participants at 1 year following YFV (95% CI 0.13 to 0.83, p = 0.021), independent of sex, age and prior vaccination. In HIV-infected participants, each 10% increase in CD4/CD8 ratio predicted a mean 21% higher post-baseline YFV Nab titer (p = 0.024). Similarly, each 10% increase in KT ratio predicted a mean 21% lower post-baseline YFV Nab titer (p = 0.009). Viremia by Human Pegivirus was not significantly associated with NAb titers. CONCLUSIONS: HIV infection appears to decrease the durability of NAb responses to YFV, an effect that may be predicted by lower CD4/CD8 ratio or higher KT ratio.

CD4/CD8 Ratio Predicts Yellow Fever Vaccine-Induced Antibody Titers in Virologically Suppressed HIV-Infected Patients.

BACKGROUND: Yellow fever vaccine (YFV) induces weaker immune responses in HIV-infected individuals. However, little is known about YFV responses among antiretroviral-treated patients and potential immunological predictors of YFV response in this population. METHODS: We enrolled 34 antiretroviral therapy (ART)-treated HIV-infected and 58 HIV-uninfected adults who received a single YFV dose to evaluate antibody levels and predictors of immunity, focusing on CD4(+) T-cell count, CD4(+)/CD8(+) ratio, and Human Pegivirus (GBV-C) viremia. Participants with other immunosuppressive conditions were excluded. RESULTS: Median time since YFV was nonsignificantly shorter in HIV-infected participants than in HIV-uninfected participants (42 and 69 months, respectively, P = 0.16). Mean neutralizing antibody (NAb) titers was lower in HIV-infected participants than HIV-uninfected participants (3.3 vs. 3.6 log10mIU/mL, P = 0.044), a difference that remained significant after adjustment for age, sex, and time since vaccination (P = 0.024). In HIV-infected participants, lower NAb titers were associated with longer time since YFV (rho: -0.38, P = 0.027) and lower CD4(+)/CD8(+) ratio (rho: 0.42, P = 0.014), but not CD4(+) T-cell count (P = 0.52). None of these factors were associated with NAb titers in HIV-uninfected participant. GBV-C viremia was not associated with difference in NAb titers overall or among HIV-infected participants. CONCLUSIONS: ART-treated HIV-infected individuals seem to have impaired and/or less durable responses to YFV than HIV-uninfected individuals, which were associated with lower CD4(+)/CD8(+) ratio, but not with CD4(+) T-cell count. These results supports the notion that low CD4(+)/CD8(+) ratio, a marker linked to persistent immune activation, is a better indicator of functional immune disturbance than CD4(+) T-cell count in patients with successful ART.

Avaliação do potencial antioxidante in vitro do composto ciano-carvona / Assessment of in vitro antioxidant potential of the terpene compound cyano-carvone

O presente estudo avaliou o potencial antioxidante in vitro da ciano-carvona contra a formação de substâncias reativas com o ácido tiobarbitúrico (TBARS), radical hidroxila e produção de óxido nítrico. Observou-se que a ciano-carvona (0,9, 1,8, 3,6, 5,4 e 7,2 μg/mL), foi capaz de prevenir a peroxidação lipídica induzida por 2,2'-azobis-2-amidinopropano (AAPH), inibindo a quantidade de TBARS formada. Resultado semelhante foi obtido com o Trolox (140 μg/mL), um análogo sintético hidrofílico do α-tocoferol, que é largamente usado como padrão antioxidante. Este resultado sugere que a ciano-carvona pode exercer um efeito antioxidante contra a peroxidação lipídica in vivo. A ciano-carvona também produziu uma remoção do radical hidroxila, sugerindo uma possível capacidade de proteção contra danos celulares in vitro produzidos por este radical. O Trolox também reduziu significativamente a quantidade deste radical. Em relação à produção de óxido nítrico, foi detectado uma diminuição significativa na produção deste composto pela ciano-carvona, demonstrando uma propriedade antioxidante in vitro, um achado que pode ser explorado para a proteção in vivo das biomoléculas, como lipídios da membrana celular. A ciano-carvona revelou potencial antioxidante in vitro, por meio da capacidade de remoção contra radicais hidroxilas e do óxido nítrico, bem como preveniu a formação de TBARS.

The in vitro antioxidant potential of the monoterpene cyano-carvone was tested against the formation of thiobarbituric acid reactive substances (TBARS) and production of hydroxyl radical and nitric oxide. It was observed that cyano-carvone (0.9, 1.8, 3.6, 5.4 and 7.2 μg/mL) was capable of reducing lipid peroxidation induced by 2,2'-azobis-2-amidinopropane (AAPH), thus inhibiting TBARS generation. Similar results were obtained with Trolox (140 μg/mL), a synthetic analogue of the hydrophilic α-tocopherol, which is widely used as an antioxidant standard. This result suggests that cyano-carvone may exert an antioxidant effect against lipid peroxidation in vivo. Cyano-carvone also led to removal of the hydroxyl radical, indicating a potential ability to protect against in vitro cell damage produced by this radical. Trolox also reduced significantly the amount of this radical. Regarding nitric oxide production, this was significantly lowered by cyano-carvone, demonstrating an antioxidant property in vitro, which could be exploited in vivo to protect biomolecules such as lipids of the cell membrane. In sum, cyano-carvone showed an in vitro antioxidant potential, by its capacity to remove hydroxyl radicals and nitric oxide, and prevented TBARS formation.

Avaliação da toxicidade aguda e do efeito ansiolítico de um derivado sintético da carvona / Evaluation of acute toxicity and anxiolytic effect of a synthetic derivative of carvone

Objetivo: Avaliar a segurança da ciano-carvona por meio de estudos de toxicidade aguda e o seu potencial ansiolítico. Material e Métodos: Camundongos Swiss machos foram tratados com ciano-carvona (v.o) em doses crescentes de 25 a 2000 mg/kg e observados durante 14 dias em relação às alterações comportamentais e taxa de mortalidade. Posteriormente foram realizados exames hematológicos, bioquímicos e análise macroscópica dos principais órgãos. Além disso, outros grupos de animais foram tratados com as doses de 25, 50 e 75 mg/kg, para avaliação da atividade locomotora, do efeito ansiolítico e da coordenação motora. Resultados: No teste hipocrático, devido à ausência de mortalidade, a DL50 não foi determinada. Os sinais clínicos foram discretos, reversíveis e observados apenas nas maiores doses. Dessa forma, em relação às análises hematológicas e bioquímicas não foram verificadas alterações significativas. Nos estudos comportamentais verificou-se uma redução da atividade locomotora, um maior número de entradas nos braços abertos, bem como um maior tempo de permanência nos braços abertos, sugerindo um possível efeito ansiolítico. Em relação ao teste do rota rod não foi verificada alteração no tempo de permanência na barra giratória, bem como não foi detectado mudanças no número de quedas. Conclusão: Este estudo demonstrou que a ciano-carvona não apresenta toxicidade aguda, sugerindo um efeito ansiolítico que precisa ser melhor investigado para a elucidação do seu mecanismo de ação.

Objective: To evaluate the safety of cyano-carvone by means of acute toxicity studies and to investigate its anxiolytic potential. Material and Methods: Swiss male mice were treated with cyano-carvone (v.o) in escalating doses from 25 to 2000 mg/kg and observed for 14 days as regards behavioral changes and mortality rate. After this time period, hematological, biochemical and morphological analyses of the main macroscopic organs were carried out. In addition, other groups of animals were treated with doses of 25, 50 and 75 mg/kg in order to assess locomotor activity, anxiolytic effect and motor coordination. Results: In the Hippocratic test, the compound did not cause any deaths among the mice, thus the LD50 was not determined and clinical signs that emerged were discrete, reversible and observed only in higher doses. Accordingly, hematological and biochemical analyses did not show significant alterations. In the behavioral analysis, it was found a reduction of locomotor activity and a greater number of entries in open arms, as well as a longer time spent with open arms, suggesting an anxiolytic effect. In the Rota-rod test it was observed no change in the permanence time on the spinning rod, as well as no changes were detected for the number of falls. Conclusion: This study demonstrated that cyano-carvone has no acute toxicity, and suggests a possible anxiolytic effect that needs to be further investigated in order to elucidate its mechanism of action.

Anticonvulsant and antioxidant effects of cyano-carvone and its action on acetylcholinesterase activity in mice hippocampus.

The anticonvulsant effect of cyano-carvone, a monoterpene monocyclic, was investigated in epilepsy model induced by pilocarpine. Cyano-carvone at doses of 25, 50 or 75 mg/kg promoted a reduction of 16.7, 33 and 66.7%, respectively, against pilocarpine-induced seizures, and it was efficacious in increasing both the latency to first seizures and the survival percentage, resulting in 33.3, 67 and 91.7% of protection against death induced by seizures, respectively (P < 0.05). The reference drug atropine (25 mg/kg) also produced a significant protection (100%). Its monoterpene, at 25, 50 and 75 mg/kg, was also capable to increase the latency for installation of status epilepticus induced by pilocarpine, and presented a significant protection against lipid peroxidation and nitrite formation in mice hippocampus (P < 0.05). In addition, it was observed that the cyano-carvone pretreatment increased the acetylcholinesterase activity in mice hippocampus after pilocarpine-induced seizures. The present results clearly indicate the anticonvulsant ability of cyano-carvone, which can be, at least in part, explained by the increased activity of the acetylcholinesterase enzyme. Our data suggest that the action mechanism can also be due to a direct activation of the antioxidant enzymes that could be associated with a reduction observed in oxidative stress in mice hippocampus, probably involving an inhibition of free radical production.