RESUMEN
Mice were fed ad libitum with a normal diet (25% protein) or low-protein diets (0-12.5% protein) for a wk and then infected with a nonlethal or lethal strain of Plasmodium yoelii, that is, blood stage infection. The same diet was continued until recovery. Mice fed with a normal diet showed severe parasitemia during nonlethal infection, but survived the infection. They died within 2 wk in the case of lethal infection. However, all mice fed with low-protein diets survived without apparent parasitemia (there were small peaks of parasitemia) in cases of both nonlethal and lethal strains. These surviving mice were found to have acquired potent innate immunity, showing the expansion of NK1.1 -TCRint cells and the production of autoantibodies during malarial infection. Severe combined immunodeficiency (scid) mice, which lack TCRint cells as well as TCRhigh cells, did not survive after malarial infection of lethal strain of P. yoelii, even when low-protein diets were given. These results suggest that low-protein diets enhanced innate immunity and inversely decreased conventional immunity, and that these immunological deviations rendered mice resistant against malaria. The present outcome also reminds us of our experience in the field study of malaria, in which some inhabitants eventually avoided contracting malaria even after apparent malarial infection.
Asunto(s)
Dieta con Restricción de Proteínas , Malaria/inmunología , Malaria/prevención & control , Plasmodium yoelii/inmunología , Animales , Inmunofenotipificación , Hígado/citología , Recuento de Linfocitos , Linfocitos/clasificación , Linfocitos/inmunología , Ratones , Ratones Endogámicos C57BL , Ratones SCID , Parasitemia/inmunología , Parasitemia/prevención & control , Bazo/citología , Timo/citologíaRESUMEN
In search of compounds which show tumor-specific cytotoxic activity, two 3,5-dibenzoyl-1, 4-dihydropyridines (GB5, GB12) were found to show one or two orders higher cytotoxic activity against human tumor cell lines (squamous cell carcinoma HSC-2, HSC-3, submandibular gland carcinoma HSG, promyelocytic leukemia HL-60) than human normal cells (gingival fibroblast HGF, pulp cells HPC, periodontal ligament fibroblasts HPLF). GB5 and GB12 weakly induced several apoptosis-associated properties, such as internucleosomal DNA fragmentation, and activation of caspases -3, -8 and -9, in both HL-60 and HSC-2 cells. Western blot analysis showed that GB5 and GB12 transiently increased the expression of both anti-apoptotic protein (Bcl-2) and proapoptotic proteins (Bax and Bad) in HL-60 cells. ESR spectroscopy showed these compounds did not produce any detectable amount of radicals, nor scavenged superoxide (generated by hypoxanthine-xanthine oxidase reaction) or nitric oxide (generated by 1-hydroxy-2-oxo-3-(N-3-methyl-3-aminopropyl)-3-methyl-1-triazene), suggesting that the induction of cytotoxic action is not via a radical-mediated reaction. The present study suggests that GB5 and GB12 may induce non-apoptotic cell death in tumor cell lines.
Asunto(s)
Antineoplásicos/farmacología , Dihidropiridinas/farmacología , Apoptosis/efectos de los fármacos , Carcinoma de Células Escamosas/tratamiento farmacológico , Línea Celular Tumoral , Ensayos de Selección de Medicamentos Antitumorales , Fibroblastos/efectos de los fármacos , Depuradores de Radicales Libres/farmacología , Células HL-60 , Humanos , Óxido Nítrico/metabolismo , Neoplasias de la Glándula Submandibular/tratamiento farmacológico , Superóxidos/metabolismoRESUMEN
A variety of beta-diketones were evaluated for their cytotoxic profiles against oral human normal and tumor cells. Among 22 compounds (BD1-22) tested, the cytotoxicity of 3-formylchromone (BD17) (CC50=7.8 microg/mL) against human oral squamous cell carcinoma (HSC-2) cells was higher than that of curcumin (CC50=23.6 microg/mL). Tumor cell-specific cytotoxicity was also detected in BD17 which exhibited little cytotoxic activity against a normal human cell, gingival fibroblast (HGF). (-)-3- (BD13) (CC50=21.7 microg/mL) and (+)-3-(Trifluoroacetyl)camphor (BD12) (CC50=29.7 microg/mL) are enantiomers and showed cytotoxicity comparable to curcumin and dibenzoylmethane (BD2) (CC50=22.5 microg/mL). BD13 did not induce DNA fragmentation in HL-60 cells nor activate caspase 3, 8 and 9 in both HL-60 and HSC-2 cells, regardless of the presence or absence of FeCl3. On the other hand, BD17 was found to induce apoptosis in HSC-2 and HL-60 cells, as judged by internucleosomal DNA fragmentation, caspase 3, 8 and 9 activation and dysfunction of mitochondrial membrane potential. The cytotoxic activity of BD13, BD17 and curcumin was significantly reduced by chelation with FeCl3. The tumor-specific cytotoxicity and apoptosis-inducing activity of BD17 against human tumor cells undoubtedly warrant further studies of its efficacy as a cancer chemotherapeutic agent.
Asunto(s)
Apoptosis/efectos de los fármacos , Cetonas/farmacología , Caspasas/metabolismo , Ensayos de Selección de Medicamentos Antitumorales , Activación Enzimática/efectos de los fármacos , Células HL-60 , Humanos , Membranas Intracelulares/efectos de los fármacos , Membranas Intracelulares/fisiología , Isoenzimas , Potenciales de la Membrana/efectos de los fármacos , Mitocondrias/efectos de los fármacos , Mitocondrias/fisiología , Células Tumorales CultivadasRESUMEN
Plasmodium yoelii-infected erythrocytes were injected into mice with or without 6.5 Gy irradiation. This irradiation suppressed erythropoiesis and induced severe immunosuppression. However, these mice showed a rather delayed infection, suggesting that fresh erythrocytes may become malarial targets. In other words, malarial infection did not persist without newly generated erythrocytes in mice. We then examined erythropoiesis in the liver and bone marrow of mice with malaria. Surprisingly, erythropoiesis began in the liver. At this time, the serum level of erythropoietin (EPO) was prominently elevated and the EPO mRNA also became detectable in the kidney. Many clusters of red blood cells appeared de novo in the parenchymal space of the liver. These results revealed that malarial infection had a potential to induce the onset of hepatic erythropoiesis in mice.
Asunto(s)
Eritropoyesis/fisiología , Hígado/fisiopatología , Malaria/fisiopatología , Plasmodium yoelii , Animales , Modelos Animales de Enfermedad , Inmunohistoquímica , Leucocitos Mononucleares/fisiología , Hígado/patología , Malaria/sangre , Malaria/patología , Ratones , Ratones Endogámicos C57BL , Parasitemia/inmunología , Parasitemia/fisiopatología , Valores de Referencia , Factores de TiempoRESUMEN
We have recently found that millimolar concentrations of sodium fluoride (NaF) induced apoptotic cell death, characterized by caspase activation and DNA fragmentation, in tumor cell lines. This finding paved the way to investigating the interaction between NaF and the oral environment. As an initial step, we investigated redox compounds, metals and saliva, which may modify the cytotoxic activity of NaF against a human oral squamous cell carcinoma cell line (HSC-2). The minimum exposure time to NaF required for cytotoxicity induction was 8 hours. Noncytotoxic concentrations of antioxidants (sodium ascorbate, gallic acid, epigallocatechin gallate, chlorogenic acid, curcumin, superoxide dismutase, catalase), oxidants (hydrogen peroxide, sodium hypochlorite), metals (CuCl, CuCl2, FeCl2, FeCl3, CoCl2) or saliva neither protected against, nor enhanced the cytotoxic activity of NaF. Cytotoxic concentrations of these compounds produced somewhat additive, but not synergistic, effects on the cytotoxicity of NaF. ESR analysis demonstrated that NaF did not apparently change the radical intensity of sodium ascorbate and gallic acid, measured under alkaline conditions. During the cell death induction in human promyelocytic leukemia HL-60 cells by NaF, the consumption of glucose rapidly declined, followed by a decline in the consumption of major amino acids. The present study suggests that the cytotoxic activity of NaF is not regulated by the redox mechanism, but rather linked to the rapid decline in glucose consumption at early stage.
Asunto(s)
Antioxidantes/farmacología , Metales/farmacología , Oxidantes/farmacología , Saliva/química , Fluoruro de Sodio/farmacología , Aminoácidos/metabolismo , Carcinoma de Células Escamosas/tratamiento farmacológico , Carcinoma de Células Escamosas/metabolismo , Línea Celular Tumoral , Interacciones Farmacológicas , Glucosa/metabolismo , Células HL-60 , Humanos , Oxidación-ReducciónRESUMEN
Immunological states during human malarial infection were examined. In parallel with parasitemia and anemia, granulocytosis was induced in the blood of patients, especially those infected with Plasmodium (P.) falciparum. At that time, the level of lymphocytes remained unchanged or slightly increased in the blood. However, the distribution of lymphocyte subsets was modulated, showing that the proportion of CD56(+)T cells, CD57(+)T cells, and gammadeltaT cells (i.e. all unconventional T cells) had increased in patients infected with P. falciparum or P. vivax. This phenomenon occurred at the early phase of infection and disappeared in the course of recovery. The data from patients with multiple attacks of P. vivax infection showed that there was no augmentation of these responses. In adult cases, the increase in the proportion of unconventional T cells seemed to closely parallel disease severity. However, all these responses were weak in children, even those infected with P. falciparum. In conjunction with accumulating evidence from mouse malaria experiments, the present results suggest that the immunological state induced by malarial infection might mainly be an event of unconventional T cells and that the immunological memory might not be long-lasting, possibly due to the properties of unconventional T cells.
Asunto(s)
Células Asesinas Naturales/inmunología , Activación de Linfocitos , Malaria Falciparum/inmunología , Malaria Vivax/inmunología , Linfocitos T/inmunología , Adolescente , Adulto , Animales , Antígenos de Protozoos/inmunología , Antígenos de Superficie/inmunología , Biomarcadores/análisis , Antígeno CD56/análisis , Antígenos CD57/análisis , Niño , Preescolar , Femenino , Humanos , Inmunidad Innata , Células Asesinas Naturales/química , Cinética , Masculino , Persona de Mediana Edad , Plasmodium falciparum/crecimiento & desarrollo , Plasmodium vivax/crecimiento & desarrollo , Subgrupos de Linfocitos T/clasificación , Subgrupos de Linfocitos T/inmunología , Factores de TiempoRESUMEN
Natural killer T (NKT) cells and CD5(+)B cells were searched for in various immune organs of autoimmune prone (NZBxNZW)F(1) (NZB/W F(1)) mice. The number of lymphocytes increased in the liver, spleen, and peritoneal cavity after the onset of disease (at the age of 30 weeks) while the number of thymocytes decreased at that time. Prominent changes of lymphocyte subsets were seen in the liver and peritoneal cavity, namely, expansion of IL-2Rbeta(+)TCRalpha beta(int) cells in the liver and of CD5(+)B220(+) cells in the peritoneal cavity. The majority of TCRalpha beta(int) cells in the liver were NK1.1(+), and CD5(+)B cells in the peritoneal cavity were CD1d(+). Proteinuria became prominent in NZB/W F(1) mice with the progression of disease. In parallel with this progression, the proportion of NKT cells decreased slightly in the liver, but their absolute number remained at a high level in this organ. These NKT cells were CD4(+) and used an invariant chain of Valpha14Jalpha281 for TCRalpha. Reflecting the elevation of CD5(+)B cells, autoantibodies against hepatocyte cytoplasmand denatured DNA were detected in sera. Although NKT cells are known to be immunoregulatory cells in some autoimmune mice, the present results raise the possibility that NKT cells as well as CD5(+)B cells might be associated with the onset of autoimmune diseases in NZB/W F(1) mice. Indeed, NKT cells in F(1) mice had a high potential to induce autoimmune-like inflammationwhen alpha-galactosylceramide was administered or when active NKT cells were transferred into young F(1) mice.
Asunto(s)
Enfermedades Autoinmunes/inmunología , Subgrupos de Linfocitos B/inmunología , Antígenos CD4/análisis , Antígenos CD5/análisis , Células Asesinas Naturales/inmunología , Trastornos Linfoproliferativos/inmunología , Subgrupos de Linfocitos T/inmunología , Traslado Adoptivo , Animales , Anticuerpos Antinucleares/inmunología , Especificidad de Anticuerpos , Antígenos CD1/análisis , Antígenos CD1d , Autoanticuerpos/inmunología , Enfermedades Autoinmunes/patología , Subgrupos de Linfocitos B/patología , Cruzamientos Genéticos , Citoplasma/inmunología , ADN/inmunología , Progresión de la Enfermedad , Galactosilceramidas/inmunología , Galactosilceramidas/toxicidad , Hepatocitos/inmunología , Glomérulos Renales/patología , Células Asesinas Naturales/patología , Hígado/patología , Recuento de Linfocitos , Trastornos Linfoproliferativos/patología , Ratones , Ratones Endogámicos C57BL , Ratones Endogámicos MRL lpr , Ratones Endogámicos NZB , Cavidad Peritoneal/patología , Proteinuria/etiología , Proteinuria/patología , Receptores de Antígenos de Linfocitos T alfa-beta/análisis , Organismos Libres de Patógenos Específicos , Bazo/patología , Subgrupos de Linfocitos T/patología , Subgrupos de Linfocitos T/trasplanteRESUMEN
Athymic nude mice carry neither conventional T cells nor NKT cells of thymic origin. However, NK1.1(-)TCR(int) cells are present in the liver and other immune organs of athymic mice, because these lymphocyte subsets are truly of extrathymic origin. In this study, we examined whether extrathymic T cells had the capability to protect mice from malarial infection. Although B6-nu/nu mice were more sensitive to malaria than control B6 mice, these athymic mice were able to survive malaria when a reduced number of parasitized erythrocytes (5 x 10(3) per mouse) were injected. At the fulminant stage, lymphocytosis occurred in the liver and the major expanding lymphocytes were NK1.1(-)TCR(int) cells (IL-2Rbeta(+)TCRalphabeta(+)). Unconventional CD8(+) NKT cells (V(alpha)14(-)) also appeared. Similar to the case of B6 mice, autoantibodies (IgM type) against denatured DNA appeared during malarial infection. Immune lymphocytes isolated from the liver of athymic mice which had recovered from malaria were capable of protecting irradiated euthymic and athymic mice from malaria when cell transfer experiments were conducted. In conjunction with the previous results in euthymic mice, the present results in athymic mice suggest that the major lymphocyte subsets associated with protection against malaria might be extrathymic T cells.