Dual immune effect of iNKT cells considering human cutaneous and visceral leishmaniasis: an example of cell plasticity according to different disease scenarios

Although the semi-invariant natural killer T cells (iNKT) are a small subpopulation of cells in the peripheral blood, they are presumed to play a role in early stages of infection against various pathogens, including protozoa. This work investigates the activation status and cytokine profile of iNKT cells during human Leishmania infantum and Leishmania braziliensis infection. We studied iNKT cells in patients with symptomatic active visceral leishmaniasis (AVL) (n = 8), patients with symptomatic active cutaneous leishmaniasis (ACL) (n = 13), negative endemic controls (NEC) (n = 6) and non-endemic controls (NonEC) (n = 6), with and without total Leishmania antigen stimulus (TLA). The number of iNKT cells in the peripheral blood of patients with ACL and AVL unaltered in relation to control groups. Moreover, the iNKT cells from ACL showed a hyperactivation profile compared to patients with AVL. Additionally, TLA induced IFN-gamma production in iNKT cells from patients with ACL, while in iNKT of patients with AVL, TLA induced a decrease in this cytokine. Higher IL-17 and IL-10 production by iNKT cells from patients with ACL were also observed compared to all other groups. There were no changes in iNKT IL-10-producing cells in AVL after TLA stimulation. However, TLA induced increase in IL-10 in iNKT cells in patients with ACL. These findings suggest that, although iNKT cells showed distinct profiles in patients with ACL and AVL, they play a dual role in immune modulation in both Leishmania infection

Estudo Funcional de Células T CD4+ expressando distintas regiões V beta do receptor de célula T (TCR) em pacientes com Leishmaniose cutânea

Leishmaniasis is an endemic parasitic disease affecting 12 million worldwide. The establishment of an effective immune response directed against Leishmania is critical for the disease control. An important approach in the study of the immune response is evaluating host-parasite interaction. Different immune responses elicited by parasite infection can be directly related to distinct effector T cell subpopulations expressing specific TCR. To better understand the role that subpopulations of CD4+ T cells expressing distinct Vb usage may have in the human immune response against Leishmania braziliensis, a detailed study defining the activation state and the cytokine profile was performed with a group of well-defined cutaneous leishmaniasis patients and a group of normal individuals. Using flow cytometry, we evaluated in vitro the frequency of T CD4+ cells expressing the following V: V 2, 3, 5.1, 5.2, 8, 11, 12, 17 and 24 in the different groups. The frequency of Vb positive, CD4+ within CD4+ T cells was calculated without stimulus, as well as after culture with soluble Leishmania antigen (SLA). Our results show that: (1) CD4+ T cells expressing distinct Vb usage, increased expression of Vb 5.2 and V 24 in cutaneous leishmaniasis as compared with normal individuals; (2) cutaneous leishmanisis patients demonstrate and increase in CD4+ T cells expressing Vb 5.2, 11, 12 and 17, after stimulus with SLA; (3) Distinct populations of Vb expressing CD4+ T cells are found to expressing activation markers (HLA-DR), memory markers (CD45RO), as well as pro-inflammatory (IFN-g, TNF-a), and anti-inflammatory (IL-10), cytokines after stimulus with SLA; (4) Positive correlations between CD4+ T cells expressing Vb 5.2, 11 and 17, producing pro-inflammatory (IFN-g, TNF-a), and anti-inflammatory (IL-10), cytokines are seen after stimulus with SLA. Given that cutaneous leishmaniasis is a form of leishmaniasis that is often followed by spontaneous cure, the activation of specific subpopulations during this disease could allow the formation of an effective cellular response. This study might lead us to the discovery of immunodominant Leishmania antigens important for triggering efficient host responses against the parasite.A leishmaniose é uma doença parasitária que afeta 12 milhões de pessoas em todo o mundo. O estabelecimento de uma resposta imune efetora contra a Leishmania é crítico para o controle da doença. Uma abordagem importante no estudo da resposta imune é avaliar a interação parasito-hospedeiro. Diferenças na resposta imune produzidas pela infecção com o parasita podem estar diretamente relacionadas com a existência do padrão de expressão dos receptores antigênicos presentes nos linfócitos T antígeno-específicos e nas diferentes subpopulações de clones de células T efetoras. Desta maneira, nosso trabalho envolveu um estudo com indivíduos não infectados e com pacientes apresentando a forma clínica cutânea da leishmaniose (LC). Objetivando entender melhor o papel que podem ter as subpopulações de células T CD4+, definindo o estado de ativação e o perfil de citocinas das células T CD4+ com expressão preferencial para as regiões variáveis da cadeia beta (V) do receptor de células T (TCR), na resposta imune humana contra Leishmania braziliensis. Utilizando a técnica de citometria de fluxo, avaliamos in vitro a frequência de células T CD4+, estimuladas ou não com o antígeno solúvel de Leishmania (SLA), expressando os seguintes V: V 2, 3, 5.1, 5.2, 8, 11, 12, 17 e 24, nos diferentes grupos. Nos pacientes com LC, avaliamos o estado funcional e a ativação celular pela expressão HLA-DR e de CD45RO, além citocinas pró-inflamatórias IFN-g, TNF-a e anti-inflamatória IL-10, nas células T CD4+ com expressão preferencial para as regiões Vb do TCR. Nossos resultados indicam que: (1) Pacientes com LC possuem frequência mais elevada de células T CD4+ com expressão preferencial para as regiões V5.2 e V24 do TCR, quando comparados a indivíduos não infectados; (2) O estímulo com SLA leva à expansão de células T CD4+ com expressão preferencial das regiões V 5.2, 11, 12 e 17 nos pacientes com LC; (3) O estímulo com SLA induz aumento de expressão tanto das moléculas de ativação HLA-DR e memória CD45RO, quanto de citocinas pró-inflamatórias IFN-g, TNF-a e anti-inflamatória IL-10, por células T CD4+ expressando diferentes regiões Vb em pacientes com LC; (4) Correlações positivas entre células T CD4+ com expressão preferencial das regiões Vb 5.2, 11 e 17 do TCR, expressando citocinas pró-inflamatórias IFN-g, TNF-a e anti-inflamatórias IL-10, respectivamente, foram vistas após o estímulo com SLA, nos pacientes com LC. Visto que a leishmaniose cutânea é uma doença que, na maioria dos casos desenvolve a forma branda, seguida de cura espontânea com proteção imunológica, a ativação de subpopulações específicas pode permitir a formação de uma resposta celular efetora. Este estudo pode ajudar na descoberta de antígenos imunodominantes de Leishmania, importantes por desencadear uma resposta eficiente no hospedeiro contra o parasita

Antileishmanial Activity of Cinnamic Acid Derivatives against Leishmania infantum

Leishmania infantum is the etiological agent of visceral leishmaniasis (VL) in South America, the Mediterranean basin, and West and Central Asia. The most affected country, Brazil, reported 4297 VL cases in 2017. L. infantum is transmitted by female phlebotomine sand flies during successive blood meals. There are no validated vaccines to prevent the infection and the treatment relies on drugs that often present severe side effects, which justify the efforts to find new antileishmanial drugs. Cinnamic acid derivatives have shown several pharmacological activities, including antiparasitic action. Therefore, in the present study, the biological evaluation of cinnamic acid and thirty-four derivatives against L. infantum is reported. The compounds were prepared by several synthesis methods and characterized by spectroscopic techniques and high-resolution mass spectrometry. The results revealed that compound 32 (N-(4-isopropylbenzyl)cinnamamide) was the most potent antileishmanial agent (IC50 = 33.71 μM) with the highest selectivity index (SI > 42.46), followed by compound 15 (piperonyl cinnamate) with an IC50 = 42.80 μM and SI > 32.86. Compound 32 was slightly less potent and nineteen times more selective for the parasite than amphotericin B (MIC = 3.14 uM; SI = 2.24). In the molecular docking study, the most likely target for the compound in L. infantum was aspartyl aminopeptidase, followed by aldehyde dehydrogenase, mitochondrial. The data obtained show the antileishmanial potential of this class of compounds and may be used in the search for new drug candidates against Leishmania species

Antileishmanial Activity of Cinnamic Acid Derivatives against Leishmania infantum

Leishmania infantum is the etiological agent of visceral leishmaniasis (VL) in South America, the Mediterranean basin, and West and Central Asia. The most affected country, Brazil, reported 4297 VL cases in 2017. L. infantum is transmitted by female phlebotomine sand flies during successive blood meals. There are no validated vaccines to prevent the infection and the treatment relies on drugs that often present severe side effects, which justify the efforts to find new antileishmanial drugs. Cinnamic acid derivatives have shown several pharmacological activities, including antiparasitic action. Therefore, in the present study, the biological evaluation of cinnamic acid and thirty-four derivatives against L. infantum is reported. The compounds were prepared by several synthesis methods and characterized by spectroscopic techniques and high-resolution mass spectrometry. The results revealed that compound 32 (N-(4-isopropylbenzyl)cinnamamide) was the most potent antileishmanial agent (IC50 = 33.71 μM) with the highest selectivity index (SI &gt; 42.46), followed by compound 15 (piperonyl cinnamate) with an IC50 = 42.80 μM and SI &gt; 32.86. Compound 32 was slightly less potent and nineteen times more selective for the parasite than amphotericin B (MIC = 3.14 uM; SI = 2.24). In the molecular docking study, the most likely target for the compound in L. infantum was aspartyl aminopeptidase, followed by aldehyde dehydrogenase, mitochondrial. The data obtained show the antileishmanial potential of this class of compounds and may be used in the search for new drug candidates against Leishmania species.</jats:p

Anti-<i>Leishmania</i> and cytotoxic activities of perillaldehyde epoxide synthetic positional isomers

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.</p

CD4(+)T cells defined by their Vb T cell receptor expression are associated with immunoregulatory profiles and lesion size in human leishmaniasis

Submitted by Nuzia Santos ([email protected]) on 2014-11-06T13:28:44Z No. of bitstreams: 1 CD4+ T cells defined by their Vβ T cell receptor expression are associated with immunoregulatory profiles and lesion size in human leishmaniasis - Keesen - 2011 - Clinical & Experimental Immunology - Wiley Online Library.pdf: 789362 bytes, checksum: 3905cb918aedef1e39fbd318cda2e9a2 (MD5)Approved for entry into archive by Nuzia Santos ([email protected]) on 2014-11-06T15:10:19Z (GMT) No. of bitstreams: 1 CD4+ T cells defined by their Vβ T cell receptor expression are associated with immunoregulatory profiles and lesion size in human leishmaniasis - Keesen - 2011 - Clinical & Experimental Immunology - Wiley Online Library.pdf: 789362 bytes, checksum: 3905cb918aedef1e39fbd318cda2e9a2 (MD5)Made available in DSpace on 2014-11-06T15:10:19Z (GMT). No. of bitstreams: 1 CD4+ T cells defined by their Vβ T cell receptor expression are associated with immunoregulatory profiles and lesion size in human leishmaniasis - Keesen - 2011 - Clinical & Experimental Immunology - Wiley Online Library.pdf: 789362 bytes, checksum: 3905cb918aedef1e39fbd318cda2e9a2 (MD5) Previous issue date: 2011Universidade Federal de Minas Gerais. Departamento de Bioquímica e Imunologia. Belo Horizonnte, MG, Brasil/Santa Casa Hospital. Instituto para Educação e Pesquisa. Belo Horizonte, MG, BrasilFundação Oswaldo Cruz. Centro de Pesquisas René Rachou. Belo Horizonte, MG, BrasilUniversidade Federal de Minas Gerais. Departamento de Morfologia. Belo Horizonte, MG, BrasilUniversidade Federal da Bahia. Hospital Edgard Santos. Immunology Service. Salvador, Brazil/ Instituto Nacional de Ciência e Tecnologia em Doenças TropicaisUniversidade Federal da Bahia. Hospital Edgard Santos. Immunology Service. Salvador, Brazil/ Instituto Nacional de Ciência e Tecnologia em Doenças TropicaisUniversidade Federal da Bahia. Hospital Edgard Santos. Immunology Service. Salvador, Brazil/ Instituto Nacional de Ciência e Tecnologia em Doenças TropicaisUniversidade Federal de Minas Gerais. Departamento de Morfologia. Belo Horizonte, MG, Brasil/Instituto Nacional de Ciência e Tecnologia em Doenças TropicaisSanta Casa Hospital. Instituto para Educação e Pesquisa. Belo Horizonte, MG, Brasil/ Instituto Nacional de Ciência e Tecnologia em Doenças Tropicais/SRI International. Biosciences Division. Center for Infections Disease Research. Menlo Park, CA, USALeishmaniasis is caused by infection with the protozoan parasite, Leishmania, that parasitizes human cells, and the cellular immune response is essential for controlling infection. In order to measure the host T cell response to Leishmania infection, we have measured the expansion, activation state and functional potential of specific T cells as identified by their T cell receptor Vb region expression. In a group of cutaneous leishmaniasis (CL) patients, we evaluated these characteristics in nine different T cell subpopulations as identified by their Vb region expression, before and after specific Leishmania antigen stimulation. Our results show: (1) an increase in CD4+ T cells expressing Vb 5•2 and Vb 24 in CL compared to controls; (2) a Leishmania antigeninduced increase in CD4+ T cells expressing Vb 5•2, 11, 12 and 17; (3) a profile of previous activation of CD4+Vb 5•2-, 11- and 24-positive T cells,with higher expression of CD45RO, HLA-DR, interferon-g, tumour necrosis factor-a and interleukin-10 compared to other Vb-expressing subpopulations; (4) a positive correlation between higher frequencies of CD4+Vb5•2+ T cells and larger lesions; and (5) biased homing of CD4+ T cells expressing Vb 5•2 to the lesion site. Given that CL disease involves a level of pathology (ulcerated lesions) and is often followed by long-lived protection and cure, the identification of specific subpopulations active in this form of disease could allow for the discovery of immunodominant Leishmania antigens important for triggering efficient host responses against the parasite, or identify cell populations most involved in pathology

Differential regulatory T cell signature after recovery from mild COVID-19

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is characterized by a range of symptoms in which host immune response have been associated with disease progression. However, the putative role of regulatory T cells (Tregs) in determining COVID-19 outcomes has not been thoroughly investigated. Here, we compared peripheral Tregs between volunteers not previously infected with SARS-CoV-2 (healthy control [HC]) and volunteers who recovered from mild (Mild Recovered) and severe (Severe Recovered) COVID-19. Peripheral blood mononuclear cells (PBMC) were stimulated with SARS-CoV-2 synthetic peptides (Pool Spike CoV-2 and Pool CoV-2) or staphylococcal enterotoxin B (SEB). Results of a multicolor flow cytometric assay showed higher Treg frequency and expression of IL-10, IL-17, perforin, granzyme B, PD-1, and CD39/CD73 co-expression in Treg among the PBMC from the Mild Recovered group than in the Severe Recovered or HC groups for certain SARS-CoV-2 related stimulus. Moreover, Mild Recovered unstimulated samples presented a higher Tregs frequency and expression of IL-10 and granzyme B than did that of HC. Compared with Pool CoV-2 stimuli, Pool Spike CoV-2 reduced IL-10 expression and improved PD-1 expression in Tregs from volunteers in the Mild Recovered group. Interestingly, Pool Spike CoV-2 elicited a decrease in Treg IL-17+ frequency in the Severe Recovered group. In HC, the expression of latency-associated peptide (LAP) and cytotoxic granule co-expression by Tregs was higher in Pool CoV-2 stimulated samples. While Pool Spike CoV-2 stimulation reduced the frequency of IL-10+ and CTLA-4+ Tregs in PBMC from volunteers in the Mild Recovered group who had not experienced certain symptoms, higher levels of perforin and perforin+granzyme B+ co-expression by Tregs were found in the Mild Recovered group in volunteers who had experienced dyspnea. Finally, we found differential expression of CD39 and CD73 among volunteers in the Mild Recovered group between those who had and had not experienced musculoskeletal pain. Collectively, our study suggests that changes in the immunosuppressive repertoire of Tregs can influence the development of a distinct COVID-19 clinical profile, revealing that a possible modulation of Tregs exists among volunteers of the Mild Recovered group between those who did and did not develop certain symptoms, leading to mild disease.</jats:p