In a previous immunogenicity and efficacy study in mice, montanide ISA 720 （MISA） was indicated to be a better adjuvant than bacillus calmette guerin vaccine （BCG） for a Leishmania vaccine. In the present study, w...In a previous immunogenicity and efficacy study in mice, montanide ISA 720 （MISA） was indicated to be a better adjuvant than bacillus calmette guerin vaccine （BCG） for a Leishmania vaccine. In the present study, we report the safety, immunogenicity and efficacy of Leishmania donovani （L. donovani） sonicated antigen delivered with alum-BCG （A1BCG）, MISA or monophosphoryl lipid A （MPLA） in vervet monkeys following intradermal inoculums. Vaccinated and control animals were challenged with virulent L. donovani parasites and the parasitic burden was determined. Only animals vaccinated with alum-BCG adversely reacted to the inoculum by produc- ing ulcerative erythematous skin indurations. Non-parametric ANOVA followed by a post test showed signifi- cantly higher IgG antibodies, and revealed the presence of lymphoproliferative and interferon gamma responses in both AIBCG＋Ag and MISA＋Ag as compared to the MPLA＋Ag or other groups （P 〈 0.001）. We conclude that L. donovani sonicated antigen containing MISA is safe and is associated with protective immune response against Leishmania donovani infection in the vervet monkey model.展开更多
Objective: To compare diagnostic accuracy and agreement between direct agglutination test and rK39 rapid tests for diagnosis of visceral leishmaniasis in an endemic area, the Doka area in Eastern Sudan.Methods: Stored...Objective: To compare diagnostic accuracy and agreement between direct agglutination test and rK39 rapid tests for diagnosis of visceral leishmaniasis in an endemic area, the Doka area in Eastern Sudan.Methods: Stored sera of confirmed visceral leishmaniasis cases, unconfirmed visceral leishmaniasis-suspects and negative controls were tested by direct agglutination test and rK39 rapid test. The sera were collected from the Doka area in Eastern Sudan. Diagnostic accuracy of direct agglutination test and rK39 rapid test was assessed in terms of sensitivity, specificity, positive predictive value and negative predictive value, estimated at 95% confidence interval(CI). Agreement between the two tests was determined by the kappa(κ) value.Results: Taking lymph node aspiration of Leishmania as a gold standard, direct agglutination test showed 91.0% sensitivity, 99.3% specificity, resulting in a positive and negative predictive value of 99.3% and 91.0%, respectively. In contrast, the sensitivity of rK39 rapid test was 85.2% and specificity 98.6%, resulting in a positive and negative predictive value of 98.5% and 85.9%, respectively. Most(81.3%) of the confirmed visceral leishmaniasis sera revealed strong antibody titers(≥1:6 400). Some sera(n=5) that were positively tested with rK39 rapid test were negative in direct agglutination test(≤1:800);in contrast, direct agglutination test was positive in 12 confirmed visceral leishmaniasis sera that were negatively tested with rK39 rapid test. There was moderate to good agreement between direct agglutination test and rK39 rapid test for confirmed visceral leishmaniasis patients(κ=0.42, 95% CI=0.21-0.63) and control sera(κ=0.80, 95% CI=0.41-1.00).Conclusions: Both direct agglutination test and rK39 rapid test are satisfactory test systems for visceral leishmaniasis diagnosis in East Sudan. Their simplicity makes them ideal for first healthcare in rural areas. These data are relevant also for other East African endemic countries because of the geographical and overlapping distribution of the Leishmania parasite.展开更多
Leishmania donovani is one of the causative agents of visceral leishmaniasis.The immune response against Leishmania depends on CD4^(+)T helper type 1 cells.The immune system is unable to combat Leishmania because the ...Leishmania donovani is one of the causative agents of visceral leishmaniasis.The immune response against Leishmania depends on CD4^(+)T helper type 1 cells.The immune system is unable to combat Leishmania because the parasite can exert several immune suppressive mechanisms that facilitate escaping the immune responses.One of these mechanisms is the up-regulation of programmed death-1/programmed death ligand-1 pathway which causes T cells to undergo exhaustion.Autophagy is strongly linked to the immune response,with some research indicating that activating autophagy reduces the immune response to some intracellular pathogens,while others indicate that activating autophagy limits the growth of intracellular pathogens.Leishmania was found to subvert the host defense mechanisms for its own persistence,such as Leishmania-induced autophagy modulation.Leishmania was reported to activate autophagy in different studies,thus getting a dual benefit by evading the immune system and simultaneously utilizing the autophagy byproducts as nutrients.In this review,we introduced different immune evasion/suppressive mechanisms used by Leishmania,and different immunotherapies which were developed accordingly.We focused on the programmed death-1/programmed death ligand-1 pathway as well as autophagy with the potential interplay of both mechanisms.展开更多
Visceral leishmaniasis (VL) is a pestilent form of leishmaniasis that chiefly impinges the poorest sections of the society. The prototypical therapeutic interventions in vogue are handicapped due to toxicity and alarm...Visceral leishmaniasis (VL) is a pestilent form of leishmaniasis that chiefly impinges the poorest sections of the society. The prototypical therapeutic interventions in vogue are handicapped due to toxicity and alarming increase in drug resistance. In the absence of vaccines, progressive emergence of HIV-VL co-infection and relapse in the form of post kala-azar dermal leishmaniasis, have fuelled the quest for alternative therapies. Herein, we report antileishmanial activity of Piper nigrum, which is endowed with multifarous medicinal properties. Hexane (PNH) and ethanolic (PNE) extracts of P. nigrum substantially inhibited the growth of Leishmania donovani promastigotes with 50% inhibitory concentration (IC50) of 31.6 and 37.8 μg·ml-1, respectively. Growth reversibility analysis revealed the leishmanicidal effect of PNH which caused cell shrinkage and flagellar disruption. In contrast, PNE treated promastigotes showed partial effect. PNH and PNE also abrogated the growth of intra-macrophagic Leishmania amastigotes with IC50 of 14.6 and 18.3 μg·ml-1, respectively. Anti-amastigote efficacy of PNH was accompanied by higher selectivity over host macrophages than PNE. Gas-Chromatography-Mass Spectrometry showed the presence of several secondary metabolites such as trans-β-caryophyllene, piperine, β-bisabolene and other sesquiterpenes in PNH and piperine, δ-(sup 9)-cis oleic acid and piperyline in PNE. Conclusively, our work revealed discernible antileishmanial activity of P. nigrum extracts.展开更多
Aim: To evaluate in vitro the effectiveness of several anti-infective agents alone and in combination against Leishmania donovani. Method: A convenient stratified sampling method was used to obtain selected anti-infec...Aim: To evaluate in vitro the effectiveness of several anti-infective agents alone and in combination against Leishmania donovani. Method: A convenient stratified sampling method was used to obtain selected anti-infective agents. For individual drug samples, Half Maximal Inhibitory Concentrations (IC<sub>50</sub>) were obtained using the broth dilution method. The IC<sub>50’s</sub> of the drugs which were active against L. donovani were used as reference values to prepare drug combinations for the modified microdilution checkerboard method. Results: Five (5) out of the fifty-six (56) drugs used showed activity (inhibition of cell growth) against L. donovani cells. They include Quinine sulphate (IC<sub>50</sub> = 0.089 μg/ml), gentamicin (IC<sub>50</sub> = 8.1 μg/ml), amodiaquine (IC<sub>50</sub> = 138 μg/ml) and the two standard drugs: Amphotericin B (IC<sub>50</sub> = 6.3 μg/ml) and Pentamidine (IC<sub>50</sub> = 25 μg/ml). The remaining fifty-one (51) drugs did not show any inhibition within the range of concentrations used (1.25 - 160 μg/ml). The drug combinations of Pentamidine/Amodiaquine, Pentamidine/ Quinine sulphate, Pentamidine/Gentamicin, Amphotericin B/Quinine Sulphate, Amphotericin B/ Gentamicin, Amodiaquine/Quinine sulphate and Amodiaquine/Gentamicin showed synergistic effects against L. donovani whereas the Amphotericin B/Amodiaquine combination was antagonistic. Notable in the results obtained was the high effectiveness of quinine sulphate in inhibiting the growth of L. donovani. Quinine sulphate, though not indicated for leishmania treatment, was more effective than the two standard drugs and has a potential of playing a significant role in the treatment of leishmaniasis. Conclusion: This study has revealed five (5) anti-infective agents that by themselves or in combinations show activity against L. donovani. Some of the drug combinations which showed synergism should further be investigated. These results have to be confirmed by in vivo studies to define their roles in leishmaniasis treatment.展开更多
<em>L. donovani</em> infections (visceral and post kala-azar dermal leishmaniases) are characterized by infection-induced reversible immune suppression. Autoimmunity is a well-documented phenomenon among p...<em>L. donovani</em> infections (visceral and post kala-azar dermal leishmaniases) are characterized by infection-induced reversible immune suppression. Autoimmunity is a well-documented phenomenon among patients with primary immune deficiencies. This study aimed to study auto-immune phenomena accompanying <em>L. donovani</em> infections. In a prospective case-controlled study and following informed consent, 155 individuals with visceral leishmaniasis (VL;<em>n</em> = 62), post kala-azar dermal leishmaniasis (PKDL;<em>n</em> = 31) and apparently healthy volunteers (<em>n</em> = 62) were recruited. Sera antinuclear (ANA), anti-dsDNA, anti-thyroid peroxidase (TPO), anti-smooth muscles (ASMA) and F-actin auto-antibodies were measured using ELISA and indirect immune-fluorescence assay. The mean ages of VL, PDKL patients and apparently healthy volunteers were: 17.5 ± 12.5, 15.0 ± 7.0 and 17.5 ± 9.5 years with Male:Female ratios of 2:0, 1:2 and 1:5 respectively. Significantly high frequencies of F-actin (74.2%;46/62) and ASMA (50%;31/62) auto-antibodies were seen among VL patients (<strong><em>p</em> = 0.003</strong>, <strong><em>p</em> = 0.001</strong>) compared to apparently healthy volunteers. Likewise, significantly high frequencies of F-actin (64.5%;20/31;<strong><em>p</em> = 0.001</strong>), ASMA (42%;13/31;<strong><em>p</em> = 0.003</strong>), ANA (36%;11/31;<strong><em>p</em> = 0.00</strong><strong>1</strong>) and anti-dsDNA (16%;5/31;<strong><em>p</em> = 0.01</strong>) auto-antibodies were seen among PKDL patients. Development of tissue-based autoantibodies in <em>L. donovani</em> infections probably indicates loss of peripheral tolerance with activation of circulating auto-reactive T and B cells probably contributing to disease pathogenesis (increased bilirubin/liver enzymes, prolonged QT interval/arrythmias and blood cytopenias). In conclusion, <em>L. donovani</em> infection-induced immune suppression with development of tissue-based auto-antibodies is prevalent among Sudanese patients with VL and PKDL leishmaniases and contributes to some aspects of the disease pathogenesis.展开更多
Objective:To evaluate the antileishmanial activity of methanolic extract of Aloe otallensis(A.otallensis)on the promastigote stage of Leishmania donovani(L.donovani)as compared to standard drugs and to screen its phyt...Objective:To evaluate the antileishmanial activity of methanolic extract of Aloe otallensis(A.otallensis)on the promastigote stage of Leishmania donovani(L.donovani)as compared to standard drugs and to screen its phytochemical constituents.Methods:Phytochemical screening was done by using the method mentioned by Evans and Trease on methanolic extract of the exudates of Aloe otallensis leaves.The extract was also evaluated for in vitro antileishmanial activity against L.donavani which is found from the Parasitology Unit of Black Lion Hospital.The result was compared to standard drugs of sodium stibogluconate,milfostin and paramomycin.Results:The extract has a good antileishmanial activity with an IC_(50)of 0.1230μg/mL on L.donovani(AM 563).The experimental data showed that relatively it had better activity than paramomycin and milfostin but less activity than sodium stibogluconate.The data analyses were done by GraphPad Prism version 5 software after it was read by ELISA reader at the wave length of 650 nm.The phytochemical screening of the exudates of A.otallensis showed the presence of phenol,alkaloid and saponin.Conclusions:The methanol extract of the exudates of A.otallensis has a good anti-leishmaniasis activity and this may be attributed to phenol,alkaloid and saponin present in the plant.But it needs further analysis for the conformation of which constituent presents in high concentration to know which one has the strongest effect.展开更多
基金supported by a grant from the National Council for Science and Technology,Government of Kenya (No.NCST 51003 CALL2 226)
文摘In a previous immunogenicity and efficacy study in mice, montanide ISA 720 （MISA） was indicated to be a better adjuvant than bacillus calmette guerin vaccine （BCG） for a Leishmania vaccine. In the present study, we report the safety, immunogenicity and efficacy of Leishmania donovani （L. donovani） sonicated antigen delivered with alum-BCG （A1BCG）, MISA or monophosphoryl lipid A （MPLA） in vervet monkeys following intradermal inoculums. Vaccinated and control animals were challenged with virulent L. donovani parasites and the parasitic burden was determined. Only animals vaccinated with alum-BCG adversely reacted to the inoculum by produc- ing ulcerative erythematous skin indurations. Non-parametric ANOVA followed by a post test showed signifi- cantly higher IgG antibodies, and revealed the presence of lymphoproliferative and interferon gamma responses in both AIBCG＋Ag and MISA＋Ag as compared to the MPLA＋Ag or other groups （P 〈 0.001）. We conclude that L. donovani sonicated antigen containing MISA is safe and is associated with protective immune response against Leishmania donovani infection in the vervet monkey model.
文摘Objective: To compare diagnostic accuracy and agreement between direct agglutination test and rK39 rapid tests for diagnosis of visceral leishmaniasis in an endemic area, the Doka area in Eastern Sudan.Methods: Stored sera of confirmed visceral leishmaniasis cases, unconfirmed visceral leishmaniasis-suspects and negative controls were tested by direct agglutination test and rK39 rapid test. The sera were collected from the Doka area in Eastern Sudan. Diagnostic accuracy of direct agglutination test and rK39 rapid test was assessed in terms of sensitivity, specificity, positive predictive value and negative predictive value, estimated at 95% confidence interval(CI). Agreement between the two tests was determined by the kappa(κ) value.Results: Taking lymph node aspiration of Leishmania as a gold standard, direct agglutination test showed 91.0% sensitivity, 99.3% specificity, resulting in a positive and negative predictive value of 99.3% and 91.0%, respectively. In contrast, the sensitivity of rK39 rapid test was 85.2% and specificity 98.6%, resulting in a positive and negative predictive value of 98.5% and 85.9%, respectively. Most(81.3%) of the confirmed visceral leishmaniasis sera revealed strong antibody titers(≥1:6 400). Some sera(n=5) that were positively tested with rK39 rapid test were negative in direct agglutination test(≤1:800);in contrast, direct agglutination test was positive in 12 confirmed visceral leishmaniasis sera that were negatively tested with rK39 rapid test. There was moderate to good agreement between direct agglutination test and rK39 rapid test for confirmed visceral leishmaniasis patients(κ=0.42, 95% CI=0.21-0.63) and control sera(κ=0.80, 95% CI=0.41-1.00).Conclusions: Both direct agglutination test and rK39 rapid test are satisfactory test systems for visceral leishmaniasis diagnosis in East Sudan. Their simplicity makes them ideal for first healthcare in rural areas. These data are relevant also for other East African endemic countries because of the geographical and overlapping distribution of the Leishmania parasite.
文摘Leishmania donovani is one of the causative agents of visceral leishmaniasis.The immune response against Leishmania depends on CD4^(+)T helper type 1 cells.The immune system is unable to combat Leishmania because the parasite can exert several immune suppressive mechanisms that facilitate escaping the immune responses.One of these mechanisms is the up-regulation of programmed death-1/programmed death ligand-1 pathway which causes T cells to undergo exhaustion.Autophagy is strongly linked to the immune response,with some research indicating that activating autophagy reduces the immune response to some intracellular pathogens,while others indicate that activating autophagy limits the growth of intracellular pathogens.Leishmania was found to subvert the host defense mechanisms for its own persistence,such as Leishmania-induced autophagy modulation.Leishmania was reported to activate autophagy in different studies,thus getting a dual benefit by evading the immune system and simultaneously utilizing the autophagy byproducts as nutrients.In this review,we introduced different immune evasion/suppressive mechanisms used by Leishmania,and different immunotherapies which were developed accordingly.We focused on the programmed death-1/programmed death ligand-1 pathway as well as autophagy with the potential interplay of both mechanisms.
文摘Visceral leishmaniasis (VL) is a pestilent form of leishmaniasis that chiefly impinges the poorest sections of the society. The prototypical therapeutic interventions in vogue are handicapped due to toxicity and alarming increase in drug resistance. In the absence of vaccines, progressive emergence of HIV-VL co-infection and relapse in the form of post kala-azar dermal leishmaniasis, have fuelled the quest for alternative therapies. Herein, we report antileishmanial activity of Piper nigrum, which is endowed with multifarous medicinal properties. Hexane (PNH) and ethanolic (PNE) extracts of P. nigrum substantially inhibited the growth of Leishmania donovani promastigotes with 50% inhibitory concentration (IC50) of 31.6 and 37.8 μg·ml-1, respectively. Growth reversibility analysis revealed the leishmanicidal effect of PNH which caused cell shrinkage and flagellar disruption. In contrast, PNE treated promastigotes showed partial effect. PNH and PNE also abrogated the growth of intra-macrophagic Leishmania amastigotes with IC50 of 14.6 and 18.3 μg·ml-1, respectively. Anti-amastigote efficacy of PNH was accompanied by higher selectivity over host macrophages than PNE. Gas-Chromatography-Mass Spectrometry showed the presence of several secondary metabolites such as trans-β-caryophyllene, piperine, β-bisabolene and other sesquiterpenes in PNH and piperine, δ-(sup 9)-cis oleic acid and piperyline in PNE. Conclusively, our work revealed discernible antileishmanial activity of P. nigrum extracts.
文摘Aim: To evaluate in vitro the effectiveness of several anti-infective agents alone and in combination against Leishmania donovani. Method: A convenient stratified sampling method was used to obtain selected anti-infective agents. For individual drug samples, Half Maximal Inhibitory Concentrations (IC<sub>50</sub>) were obtained using the broth dilution method. The IC<sub>50’s</sub> of the drugs which were active against L. donovani were used as reference values to prepare drug combinations for the modified microdilution checkerboard method. Results: Five (5) out of the fifty-six (56) drugs used showed activity (inhibition of cell growth) against L. donovani cells. They include Quinine sulphate (IC<sub>50</sub> = 0.089 μg/ml), gentamicin (IC<sub>50</sub> = 8.1 μg/ml), amodiaquine (IC<sub>50</sub> = 138 μg/ml) and the two standard drugs: Amphotericin B (IC<sub>50</sub> = 6.3 μg/ml) and Pentamidine (IC<sub>50</sub> = 25 μg/ml). The remaining fifty-one (51) drugs did not show any inhibition within the range of concentrations used (1.25 - 160 μg/ml). The drug combinations of Pentamidine/Amodiaquine, Pentamidine/ Quinine sulphate, Pentamidine/Gentamicin, Amphotericin B/Quinine Sulphate, Amphotericin B/ Gentamicin, Amodiaquine/Quinine sulphate and Amodiaquine/Gentamicin showed synergistic effects against L. donovani whereas the Amphotericin B/Amodiaquine combination was antagonistic. Notable in the results obtained was the high effectiveness of quinine sulphate in inhibiting the growth of L. donovani. Quinine sulphate, though not indicated for leishmania treatment, was more effective than the two standard drugs and has a potential of playing a significant role in the treatment of leishmaniasis. Conclusion: This study has revealed five (5) anti-infective agents that by themselves or in combinations show activity against L. donovani. Some of the drug combinations which showed synergism should further be investigated. These results have to be confirmed by in vivo studies to define their roles in leishmaniasis treatment.
文摘<em>L. donovani</em> infections (visceral and post kala-azar dermal leishmaniases) are characterized by infection-induced reversible immune suppression. Autoimmunity is a well-documented phenomenon among patients with primary immune deficiencies. This study aimed to study auto-immune phenomena accompanying <em>L. donovani</em> infections. In a prospective case-controlled study and following informed consent, 155 individuals with visceral leishmaniasis (VL;<em>n</em> = 62), post kala-azar dermal leishmaniasis (PKDL;<em>n</em> = 31) and apparently healthy volunteers (<em>n</em> = 62) were recruited. Sera antinuclear (ANA), anti-dsDNA, anti-thyroid peroxidase (TPO), anti-smooth muscles (ASMA) and F-actin auto-antibodies were measured using ELISA and indirect immune-fluorescence assay. The mean ages of VL, PDKL patients and apparently healthy volunteers were: 17.5 ± 12.5, 15.0 ± 7.0 and 17.5 ± 9.5 years with Male:Female ratios of 2:0, 1:2 and 1:5 respectively. Significantly high frequencies of F-actin (74.2%;46/62) and ASMA (50%;31/62) auto-antibodies were seen among VL patients (<strong><em>p</em> = 0.003</strong>, <strong><em>p</em> = 0.001</strong>) compared to apparently healthy volunteers. Likewise, significantly high frequencies of F-actin (64.5%;20/31;<strong><em>p</em> = 0.001</strong>), ASMA (42%;13/31;<strong><em>p</em> = 0.003</strong>), ANA (36%;11/31;<strong><em>p</em> = 0.00</strong><strong>1</strong>) and anti-dsDNA (16%;5/31;<strong><em>p</em> = 0.01</strong>) auto-antibodies were seen among PKDL patients. Development of tissue-based autoantibodies in <em>L. donovani</em> infections probably indicates loss of peripheral tolerance with activation of circulating auto-reactive T and B cells probably contributing to disease pathogenesis (increased bilirubin/liver enzymes, prolonged QT interval/arrythmias and blood cytopenias). In conclusion, <em>L. donovani</em> infection-induced immune suppression with development of tissue-based auto-antibodies is prevalent among Sudanese patients with VL and PKDL leishmaniases and contributes to some aspects of the disease pathogenesis.
文摘Objective:To evaluate the antileishmanial activity of methanolic extract of Aloe otallensis(A.otallensis)on the promastigote stage of Leishmania donovani(L.donovani)as compared to standard drugs and to screen its phytochemical constituents.Methods:Phytochemical screening was done by using the method mentioned by Evans and Trease on methanolic extract of the exudates of Aloe otallensis leaves.The extract was also evaluated for in vitro antileishmanial activity against L.donavani which is found from the Parasitology Unit of Black Lion Hospital.The result was compared to standard drugs of sodium stibogluconate,milfostin and paramomycin.Results:The extract has a good antileishmanial activity with an IC_(50)of 0.1230μg/mL on L.donovani(AM 563).The experimental data showed that relatively it had better activity than paramomycin and milfostin but less activity than sodium stibogluconate.The data analyses were done by GraphPad Prism version 5 software after it was read by ELISA reader at the wave length of 650 nm.The phytochemical screening of the exudates of A.otallensis showed the presence of phenol,alkaloid and saponin.Conclusions:The methanol extract of the exudates of A.otallensis has a good anti-leishmaniasis activity and this may be attributed to phenol,alkaloid and saponin present in the plant.But it needs further analysis for the conformation of which constituent presents in high concentration to know which one has the strongest effect.
