Gabriela Santos-gomes | Universidade Nova de Lisboa (original) (raw)
Papers by Gabriela Santos-gomes
Annals of Tropical Medicine And Parasitology, 1997
Acta Médica Portuguesa, 1998
Visceral leishmaniasis (VL) is a zoonosis in most regions where it occurs. Dogs are the most impo... more Visceral leishmaniasis (VL) is a zoonosis in most regions where it occurs. Dogs are the most important reservoir of the disease and are mainly responsible for the persistence of VL in the Paleartic and Neotropical regions. Canine leishmaniasis (CaL) is a viscerocutaneous, chronic infection with a worse prognosis than human disease. We now know that, as in man, there are some cases of asymptomatic infection. Former studies indicated that dog cutaneous parasitism becomes infectious to the insect vector in later periods of the disease, but recent studies performed by xenodiagnosis have shown that it is possible that transmission might occur earlier. The infected animal reacts with a great production of antibodies and depression of cellular immunity. Antibodies are not protective and resistance is related with active cellular immunity. The presence of Th 1 response in asymptomatic animals, sometimes without humoral response, means that the prevalence of CaL, found in epidemiological sur...
Folia parasitologica, 1996
The mechanisms which permit Leishmania to survive inside macrophages are not totally understood a... more The mechanisms which permit Leishmania to survive inside macrophages are not totally understood although it is known that prolonged culture in vitro results in loss of virulence. One of the cell surface molecules often implicated in virulence mechanisms is the glycoprotein of 63 kDa (gp63). In this work we studied changes in infectivity of L. infantum promastigotes maintained in vitro by subcultures, correlated with the proteolytic activity of gp63. It was observed that L. infantum MON-1 promastigotes became unable to establish an infection after 6 subcultures in vitro independently of the size of inoculum. This corresponded to a diminution of proteolytic activity of gp63. L. infantum MON-1 promastigotes inoculated in hamsters visceralize in the mononuclear phagocytic system accompanied by an antibody response. A correlation between antibody response, inoculum size and promastigote origin was verified. L. donovani MON-18 and L. infantum MON-24 promastigotes produced a specific humor...
Archives de l'Institut Pasteur de Tunis, 1993
Acta médica portuguesa, 1998
Visceral leishmaniasis (VL) is a zoonosis in most regions where it occurs. Dogs are the most impo... more Visceral leishmaniasis (VL) is a zoonosis in most regions where it occurs. Dogs are the most important reservoir of the disease and are mainly responsible for the persistence of VL in the Paleartic and Neotropical regions. Canine leishmaniasis (CaL) is a viscerocutaneous, chronic infection with a worse prognosis than human disease. We now know that, as in man, there are some cases of asymptomatic infection. Former studies indicated that dog cutaneous parasitism becomes infectious to the insect vector in later periods of the disease, but recent studies performed by xenodiagnosis have shown that it is possible that transmission might occur earlier. The infected animal reacts with a great production of antibodies and depression of cellular immunity. Antibodies are not protective and resistance is related with active cellular immunity. The presence of Th 1 response in asymptomatic animals, sometimes without humoral response, means that the prevalence of CaL, found in epidemiological sur...
Archives de l'Institut Pasteur de Tunis
Several small mammals were trapped in the Arrabida region (Portugal) and checked for the presence... more Several small mammals were trapped in the Arrabida region (Portugal) and checked for the presence of trypanosomes which were found in 33 of the 197 (11.1 %) M us spretus and in 9 of the 29 (31 %) Crocidura russula observed. To our knowledge, this was the first time that trypanosomes were isolated from these mammals species. In the liver of one dead C. russula was observed different parasite forms. The studies of infectivity to experimental rodents, analyses of the DNA buoyant density and the isoenzy matic profils, show that trypanosomes isolates from M. spretus were identical to Trypanosoma musculi isolates from Mus musculus. However the isolates from C. russula, although related to the isolates from murine rodents, were clearely separated from these and close to Trypanosoma microti. These findings may allow further studies on the detection of their vectors and on the study of trypanosome reproduction. Résumé : Études expérimentales de Trypanosomes (Herpetosoma) de petits mammifères portugais. Dans la région d'Arrabida (Portugal), 197 Mus spretus et 29 Crocidura russula ont été capturés. 11,1 % des M. spretus et 31 % des C. russula ont des trypanosomes qui n'avaient pas encore été signalés chez ces hôtes. Les différentes formes du parasite obser vées dans le foie d'une Crocidure trouvée morte sont décrites. L'infectivité chez des rongeurs expérimentaux, les gradients de den sité de l'ADN et les profils enzymatiques montrent que les sou ches isolées de M. spretus sont identiques à Trypanosoma musculi isolé de M us musculus. Les souches isolées de C. russula, bien qu'apparentées aux précédentes, sont plus proches de Trypano soma microti. Ces données pourraient permettre d'étendre les recherches à la découverte des vecteurs et aux phénomènes de repro duction des trypanosomes. 1. This investigation received financial support from « Instituto
Several small mammals were trapped in the Arrabida region (Portugal) and checked for the presence... more Several small mammals were trapped in the Arrabida region (Portugal) and checked for the presence of trypanosomes which were found in 33 of the 197 (11.1 %) Mus spretus and in 9 of the 29 (31 %) Crocidura russula observed. To our knowledge, this was the first time that trypanosomes were isolated from these mammals species. In the liver of one dead C. russula was observed different parasite forms. The studies of infectivity to experimental rodents, analyses of the DNA buoyant density and the isoenzy matic profils, show that trypanosomes isolates from M. spretus were identical to Trypanosoma musculi isolates from Mus musculus. However the isolates from C. russula, although related to the isolates from murine rodents, were clearely separated from these and close to Trypanosoma microti. These findings may allow further studies on the detection of their vectors and on the study of trypanosome reproduction.
Vaccine, 2014
Control of zoonotic visceral leishmaniosis can be achieved using several available drugs. These d... more Control of zoonotic visceral leishmaniosis can be achieved using several available drugs. These drugs present high toxicity and require longer treatment regimens which complicate compliance to the treatment. Other control measures directed to the vector or the reservoirs are useful tools to restrain the spreading of this disease but the effects are transitory. A safe, affordable and efficient vaccine conferring long lasting immunity should be the most cost effective way of controlling zoonotic visceral leishmaniosis. The present study aims at characterizing a cyclophilin protein 1 of Leishmania infantum (LiCyP1) and investigating whether recombinant LiCyP1 (LirCyP1) is able to confer protection against infection by evaluating viable parasite load and the generation of specific CD4(+) and CD8(+) effector and central memory T cells in rodent model. LiCyP1 is present in the cytoplasm of L. infantum amastigotes and promastigotes. Immunization of BALB/c mice with LirCyP1 confers high protection to L. infantum infection, causing a marked reduction in parasite replication in the liver and spleen. Furthermore, helper and cytotoxic memory T cell subsets able to specifically recognize parasite antigens expanded in immunized and in challenged mice. CD4(+) T cell subpopulation of intermediate phenotype (CD62L(high)CD127(low)) of challenging mice also presented an accentuated expansion after the recall. This study demonstrated that LirCyP1 confers partial protection to L. infantum infection, promoting the generation of a desired long lasting immunity. LirCyP1 can be considered a potential candidate for the design of a vaccine against zoonotic visceral leishmaniosis.
The Journal of …, 1991
ABSTRACTr: Canine leishmaniasis was studied in 1,823 dogs from the Lisbon metropolitan region. Th... more ABSTRACTr: Canine leishmaniasis was studied in 1,823 dogs from the Lisbon metropolitan region. The breeds most affected were doberman and German shepherd, independent of sex and use. Young adult (12.2%) and older dogs (14.7%) had higher prevalences of ...
Parasitology
Hepatocytes constitute the majority of hepatic cells, and play a key role in controlling systemic... more Hepatocytes constitute the majority of hepatic cells, and play a key role in controlling systemic innate immunity, via pattern-recognition receptors (PRRs) and by synthesizing complement and acute phase proteins. Leishmania infantum, a protozoan parasite that causes human and canine leishmaniasis, infects liver by establishing inside the Kupffer cells. The current study proposes the elucidation of the immune response generated by dog hepatocytes when exposed to L. infantum. Additionally, the impact of adding leishmanicidal compound, meglumine antimoniate (MgA), to parasite-exposed hepatocytes was also addressed. L. infantum presents a high tropism to hepatocytes, establishing strong membrane interactions. The possibility of L. infantum internalization by hepatocytes was raised, but not confirmed. Hepatocytes were able to recognize parasite presence, inducing PRRs [nucleotide oligomerization domain (NOD)1, NOD2 and Toll-like receptor (TLR)2] gene expression and generating a mix pro- ...
Biomedicines
The application of innovative three-dimensional (3D) spheroids cell culture strategy to Parasitol... more The application of innovative three-dimensional (3D) spheroids cell culture strategy to Parasitology offers the opportunity to closely explore host–parasite interactions. Here we present a first report on the application of 3D hepatic spheroids to unravel the immune response of canine hepatocytes exposed to Leishmania infantum. The liver, usually considered a major metabolic organ, also performs several important immunological functions and constitutes a target organ for L. infantum infection, the etiological agent of canine leishmaniasis (CanL), and a parasitic disease of major veterinary and public health concern. 3D hepatic spheroids were able to sense and immunologically react to L. infantum parasites, generating an innate immune response by increasing nitric oxide (NO) production and enhancing toll-like receptor (TLR) 2 and interleukin-10 gene expression. The immune response orchestrated by canine hepatocytes also lead to the impairment of several cytochrome P450 (CYP450) with ...
Journal of Immunology Research
This review is aimed at providing a comprehensive outline of the immune response displayed agains... more This review is aimed at providing a comprehensive outline of the immune response displayed against cutaneous leishmaniasis (CL), the more common zoonotic infection caused by protozoan parasites of the genus Leishmania. Although of polymorphic clinical presentation, classically CL is characterized by leishmaniotic lesions on the face and extremities of the patients, which can be ulcerative, and even after healing can lead to permanent injuries and disfigurement, affecting significantly their psychological, social, and economic well-being. According a report released by the World Health Organization, the disability-adjusted life years (DALYs) lost due to leishmaniasis are close to 2.4 million, annually there are 1.0–1.5 million new cases of CL, and a numerous population is at risk in the endemic areas. Despite its increasing worldwide incidence, it is one of the so-called neglected tropical diseases. Furthermore, this review provides an overview of the existing knowledge of the host i...
Veterinary Sciences
Immune system recognize and fight back foreign microorganisms and inner modifications that lead t... more Immune system recognize and fight back foreign microorganisms and inner modifications that lead to deficient cell and tissue functions. During a dog’s life, the immune system needs to adapt to different physiological conditions, assuring surveillance and protection in a careful and controlled way. Pregnancy alters normal homeostasis, requiring a balance between immunity and tolerance. The embryos and fetus should be protected from infections, while the female dog must tolerate the growing of semi-allografts in her uterus. After birth, newborn puppies are at great risk of developing infectious diseases, because their immune system is in development and immune memory is absent. Passive transfer of immunity through colostrum is fundamental for puppy survival in the first weeks of life, but hampers the development of an active immune response to vaccination. At the end of life, dogs experience a decline in the structure and functional competence of the immune system, compromising the im...
Cellular Immunology
Neutrophils are short-lived phagocytic cells equipped with several receptors for pathogen recogni... more Neutrophils are short-lived phagocytic cells equipped with several receptors for pathogen recognition and phagocytosis and have intracellular and extracellular effector mechanisms that can inactivate pathogens. Leishmaniases are diseases caused by different species of Leishmania that mainly afflicts poorer populations of tropical and subtropical regions and immunocompromised individuals. Thus, the present study aims to investigate the effector response of murine neutrophils to species of Leishmania causing American cutaneous leishmaniasis and zoonotic visceral leishmaniasis by evaluating pattern recognition receptors (PRR) and intracellular and extracellular effector microbicide activity. When exposed to Leishmania parasites, mouse neutrophils produced superoxide, released enzymes in the extracellular space and generated neutrophil extracellular traps, although PRR gene expression is negatively regulated. L. infantum, L. guyanensis, and L. shawi inhibited enzymatic activity, whereas L. amazonensis reduced the emission of extracellular structures. These findings indicate that although neutrophils trigger several microbicide mechanisms, Leishmania parasites can manipulate extracellular effector mechanisms. The present study also provides evidence that neutrophils can internalize parasites by coiling phagocytosis.
Current topics in medicinal chemistry, Jan 2, 2018
Leishmaniasis is a neglected disease caused by protozoan belonging to the Leishmania genus. There... more Leishmaniasis is a neglected disease caused by protozoan belonging to the Leishmania genus. There are at least 16 pathogenic species for humans that are able to cause different clinical forms, such as cutaneous or visceral leishmaniasis. In spite of the different species and clinical forms, the treatment is performed with few drug options that, in most cases, are considered outdated. In addition, patients under classical treatment show serious side effects during drug administration, moreover parasites are able to become resistant to medicines. Thus, it is believed and well accepted that is urgent and necessary to develop new therapeutic options to overpass these concerns about conventional therapy of leishmaniasis. The present review will focus on the efficacy, side effects and action mechanism of classic drugs used in the treatment of leishmaniasis, as well as the importance of traditional knowledge for directing a rational search toward the discovery and characterization of new a...
Veterinary parasitology, Jan 15, 2017
Canine leishmaniosis caused by L. infantum is a severe zoonotic disease. Although macrophages are... more Canine leishmaniosis caused by L. infantum is a severe zoonotic disease. Although macrophages are the definitive host cells, neutrophils are the first cells to encounter the parasite soon after its inoculation in the dermis by the phlebotomine vector. To study the interaction of dog neutrophils and L. infantum promastigotes, blood neutrophils were isolated from healthy donors and the infection was established in vitro. In the majority of the dogs, L. infantum was efficiently phagocytized by neutrophils, and oxidative (superoxide production) and non-oxidative (neutrophil elastase exocytosis) intracellular effector mechanisms were activated, but the release of neutrophil extracellular traps was minimized. Furthermore, promastigotes and culture supernatants induced neutrophil migration, but the prior contact with Leishmania inhibits chemotaxis, which might contribute to neutrophil retention at the inoculation site. Neutrophil-parasite interaction resulted in a decrease in parasite viab...
![Research paper thumbnail of Corrigendum to "Therapeutic effect of ursolic acid in experimental visceral leishmaniasis" [Int. J. Parasitol. Drugs Drug Resist. 7 (2017) 1-11]](https://attachments.academia-assets.com/68022952/thumbnails/1.jpg)
](International journal for parasitology. Drugs and drug resistance, Aug 4, 2017
In the original publication, the eighth author's surname was incorrect. The respective filiation ... more In the original publication, the eighth author's surname was incorrect. The respective filiation is corrected as above. The authors would like to apologise for any inconvenience caused.
Molecular and Cellular Probes, 2016
A loop-mediated isothermal amplification (LAMP) assay was evaluated for the detection of Theileri... more A loop-mediated isothermal amplification (LAMP) assay was evaluated for the detection of Theileria annulata infection in cattle. The results were compared with a real-time PCR used for the quantification of T. annulata parasitaemia. One hundred bovine blood samples from 16 cattle farms were tested with LAMP and real-time PCR, with T. annulata DNA being detected in 66% and 67% of the samples, respectively. The results showed that the LAMP assay detects a parasitaemia as low as 0.00025%, indicating a high analytical sensitivity of LAMP for clinical diagnosis of bovine theileriosis.
Annals of Tropical Medicine And Parasitology, 1997
Acta Médica Portuguesa, 1998
Visceral leishmaniasis (VL) is a zoonosis in most regions where it occurs. Dogs are the most impo... more Visceral leishmaniasis (VL) is a zoonosis in most regions where it occurs. Dogs are the most important reservoir of the disease and are mainly responsible for the persistence of VL in the Paleartic and Neotropical regions. Canine leishmaniasis (CaL) is a viscerocutaneous, chronic infection with a worse prognosis than human disease. We now know that, as in man, there are some cases of asymptomatic infection. Former studies indicated that dog cutaneous parasitism becomes infectious to the insect vector in later periods of the disease, but recent studies performed by xenodiagnosis have shown that it is possible that transmission might occur earlier. The infected animal reacts with a great production of antibodies and depression of cellular immunity. Antibodies are not protective and resistance is related with active cellular immunity. The presence of Th 1 response in asymptomatic animals, sometimes without humoral response, means that the prevalence of CaL, found in epidemiological sur...
Folia parasitologica, 1996
The mechanisms which permit Leishmania to survive inside macrophages are not totally understood a... more The mechanisms which permit Leishmania to survive inside macrophages are not totally understood although it is known that prolonged culture in vitro results in loss of virulence. One of the cell surface molecules often implicated in virulence mechanisms is the glycoprotein of 63 kDa (gp63). In this work we studied changes in infectivity of L. infantum promastigotes maintained in vitro by subcultures, correlated with the proteolytic activity of gp63. It was observed that L. infantum MON-1 promastigotes became unable to establish an infection after 6 subcultures in vitro independently of the size of inoculum. This corresponded to a diminution of proteolytic activity of gp63. L. infantum MON-1 promastigotes inoculated in hamsters visceralize in the mononuclear phagocytic system accompanied by an antibody response. A correlation between antibody response, inoculum size and promastigote origin was verified. L. donovani MON-18 and L. infantum MON-24 promastigotes produced a specific humor...
Archives de l'Institut Pasteur de Tunis, 1993
Acta médica portuguesa, 1998
Visceral leishmaniasis (VL) is a zoonosis in most regions where it occurs. Dogs are the most impo... more Visceral leishmaniasis (VL) is a zoonosis in most regions where it occurs. Dogs are the most important reservoir of the disease and are mainly responsible for the persistence of VL in the Paleartic and Neotropical regions. Canine leishmaniasis (CaL) is a viscerocutaneous, chronic infection with a worse prognosis than human disease. We now know that, as in man, there are some cases of asymptomatic infection. Former studies indicated that dog cutaneous parasitism becomes infectious to the insect vector in later periods of the disease, but recent studies performed by xenodiagnosis have shown that it is possible that transmission might occur earlier. The infected animal reacts with a great production of antibodies and depression of cellular immunity. Antibodies are not protective and resistance is related with active cellular immunity. The presence of Th 1 response in asymptomatic animals, sometimes without humoral response, means that the prevalence of CaL, found in epidemiological sur...
Archives de l'Institut Pasteur de Tunis
Several small mammals were trapped in the Arrabida region (Portugal) and checked for the presence... more Several small mammals were trapped in the Arrabida region (Portugal) and checked for the presence of trypanosomes which were found in 33 of the 197 (11.1 %) M us spretus and in 9 of the 29 (31 %) Crocidura russula observed. To our knowledge, this was the first time that trypanosomes were isolated from these mammals species. In the liver of one dead C. russula was observed different parasite forms. The studies of infectivity to experimental rodents, analyses of the DNA buoyant density and the isoenzy matic profils, show that trypanosomes isolates from M. spretus were identical to Trypanosoma musculi isolates from Mus musculus. However the isolates from C. russula, although related to the isolates from murine rodents, were clearely separated from these and close to Trypanosoma microti. These findings may allow further studies on the detection of their vectors and on the study of trypanosome reproduction. Résumé : Études expérimentales de Trypanosomes (Herpetosoma) de petits mammifères portugais. Dans la région d'Arrabida (Portugal), 197 Mus spretus et 29 Crocidura russula ont été capturés. 11,1 % des M. spretus et 31 % des C. russula ont des trypanosomes qui n'avaient pas encore été signalés chez ces hôtes. Les différentes formes du parasite obser vées dans le foie d'une Crocidure trouvée morte sont décrites. L'infectivité chez des rongeurs expérimentaux, les gradients de den sité de l'ADN et les profils enzymatiques montrent que les sou ches isolées de M. spretus sont identiques à Trypanosoma musculi isolé de M us musculus. Les souches isolées de C. russula, bien qu'apparentées aux précédentes, sont plus proches de Trypano soma microti. Ces données pourraient permettre d'étendre les recherches à la découverte des vecteurs et aux phénomènes de repro duction des trypanosomes. 1. This investigation received financial support from « Instituto
Several small mammals were trapped in the Arrabida region (Portugal) and checked for the presence... more Several small mammals were trapped in the Arrabida region (Portugal) and checked for the presence of trypanosomes which were found in 33 of the 197 (11.1 %) Mus spretus and in 9 of the 29 (31 %) Crocidura russula observed. To our knowledge, this was the first time that trypanosomes were isolated from these mammals species. In the liver of one dead C. russula was observed different parasite forms. The studies of infectivity to experimental rodents, analyses of the DNA buoyant density and the isoenzy matic profils, show that trypanosomes isolates from M. spretus were identical to Trypanosoma musculi isolates from Mus musculus. However the isolates from C. russula, although related to the isolates from murine rodents, were clearely separated from these and close to Trypanosoma microti. These findings may allow further studies on the detection of their vectors and on the study of trypanosome reproduction.
Vaccine, 2014
Control of zoonotic visceral leishmaniosis can be achieved using several available drugs. These d... more Control of zoonotic visceral leishmaniosis can be achieved using several available drugs. These drugs present high toxicity and require longer treatment regimens which complicate compliance to the treatment. Other control measures directed to the vector or the reservoirs are useful tools to restrain the spreading of this disease but the effects are transitory. A safe, affordable and efficient vaccine conferring long lasting immunity should be the most cost effective way of controlling zoonotic visceral leishmaniosis. The present study aims at characterizing a cyclophilin protein 1 of Leishmania infantum (LiCyP1) and investigating whether recombinant LiCyP1 (LirCyP1) is able to confer protection against infection by evaluating viable parasite load and the generation of specific CD4(+) and CD8(+) effector and central memory T cells in rodent model. LiCyP1 is present in the cytoplasm of L. infantum amastigotes and promastigotes. Immunization of BALB/c mice with LirCyP1 confers high protection to L. infantum infection, causing a marked reduction in parasite replication in the liver and spleen. Furthermore, helper and cytotoxic memory T cell subsets able to specifically recognize parasite antigens expanded in immunized and in challenged mice. CD4(+) T cell subpopulation of intermediate phenotype (CD62L(high)CD127(low)) of challenging mice also presented an accentuated expansion after the recall. This study demonstrated that LirCyP1 confers partial protection to L. infantum infection, promoting the generation of a desired long lasting immunity. LirCyP1 can be considered a potential candidate for the design of a vaccine against zoonotic visceral leishmaniosis.
The Journal of …, 1991
ABSTRACTr: Canine leishmaniasis was studied in 1,823 dogs from the Lisbon metropolitan region. Th... more ABSTRACTr: Canine leishmaniasis was studied in 1,823 dogs from the Lisbon metropolitan region. The breeds most affected were doberman and German shepherd, independent of sex and use. Young adult (12.2%) and older dogs (14.7%) had higher prevalences of ...
Parasitology
Hepatocytes constitute the majority of hepatic cells, and play a key role in controlling systemic... more Hepatocytes constitute the majority of hepatic cells, and play a key role in controlling systemic innate immunity, via pattern-recognition receptors (PRRs) and by synthesizing complement and acute phase proteins. Leishmania infantum, a protozoan parasite that causes human and canine leishmaniasis, infects liver by establishing inside the Kupffer cells. The current study proposes the elucidation of the immune response generated by dog hepatocytes when exposed to L. infantum. Additionally, the impact of adding leishmanicidal compound, meglumine antimoniate (MgA), to parasite-exposed hepatocytes was also addressed. L. infantum presents a high tropism to hepatocytes, establishing strong membrane interactions. The possibility of L. infantum internalization by hepatocytes was raised, but not confirmed. Hepatocytes were able to recognize parasite presence, inducing PRRs [nucleotide oligomerization domain (NOD)1, NOD2 and Toll-like receptor (TLR)2] gene expression and generating a mix pro- ...
Biomedicines
The application of innovative three-dimensional (3D) spheroids cell culture strategy to Parasitol... more The application of innovative three-dimensional (3D) spheroids cell culture strategy to Parasitology offers the opportunity to closely explore host–parasite interactions. Here we present a first report on the application of 3D hepatic spheroids to unravel the immune response of canine hepatocytes exposed to Leishmania infantum. The liver, usually considered a major metabolic organ, also performs several important immunological functions and constitutes a target organ for L. infantum infection, the etiological agent of canine leishmaniasis (CanL), and a parasitic disease of major veterinary and public health concern. 3D hepatic spheroids were able to sense and immunologically react to L. infantum parasites, generating an innate immune response by increasing nitric oxide (NO) production and enhancing toll-like receptor (TLR) 2 and interleukin-10 gene expression. The immune response orchestrated by canine hepatocytes also lead to the impairment of several cytochrome P450 (CYP450) with ...
Journal of Immunology Research
This review is aimed at providing a comprehensive outline of the immune response displayed agains... more This review is aimed at providing a comprehensive outline of the immune response displayed against cutaneous leishmaniasis (CL), the more common zoonotic infection caused by protozoan parasites of the genus Leishmania. Although of polymorphic clinical presentation, classically CL is characterized by leishmaniotic lesions on the face and extremities of the patients, which can be ulcerative, and even after healing can lead to permanent injuries and disfigurement, affecting significantly their psychological, social, and economic well-being. According a report released by the World Health Organization, the disability-adjusted life years (DALYs) lost due to leishmaniasis are close to 2.4 million, annually there are 1.0–1.5 million new cases of CL, and a numerous population is at risk in the endemic areas. Despite its increasing worldwide incidence, it is one of the so-called neglected tropical diseases. Furthermore, this review provides an overview of the existing knowledge of the host i...
Veterinary Sciences
Immune system recognize and fight back foreign microorganisms and inner modifications that lead t... more Immune system recognize and fight back foreign microorganisms and inner modifications that lead to deficient cell and tissue functions. During a dog’s life, the immune system needs to adapt to different physiological conditions, assuring surveillance and protection in a careful and controlled way. Pregnancy alters normal homeostasis, requiring a balance between immunity and tolerance. The embryos and fetus should be protected from infections, while the female dog must tolerate the growing of semi-allografts in her uterus. After birth, newborn puppies are at great risk of developing infectious diseases, because their immune system is in development and immune memory is absent. Passive transfer of immunity through colostrum is fundamental for puppy survival in the first weeks of life, but hampers the development of an active immune response to vaccination. At the end of life, dogs experience a decline in the structure and functional competence of the immune system, compromising the im...
Cellular Immunology
Neutrophils are short-lived phagocytic cells equipped with several receptors for pathogen recogni... more Neutrophils are short-lived phagocytic cells equipped with several receptors for pathogen recognition and phagocytosis and have intracellular and extracellular effector mechanisms that can inactivate pathogens. Leishmaniases are diseases caused by different species of Leishmania that mainly afflicts poorer populations of tropical and subtropical regions and immunocompromised individuals. Thus, the present study aims to investigate the effector response of murine neutrophils to species of Leishmania causing American cutaneous leishmaniasis and zoonotic visceral leishmaniasis by evaluating pattern recognition receptors (PRR) and intracellular and extracellular effector microbicide activity. When exposed to Leishmania parasites, mouse neutrophils produced superoxide, released enzymes in the extracellular space and generated neutrophil extracellular traps, although PRR gene expression is negatively regulated. L. infantum, L. guyanensis, and L. shawi inhibited enzymatic activity, whereas L. amazonensis reduced the emission of extracellular structures. These findings indicate that although neutrophils trigger several microbicide mechanisms, Leishmania parasites can manipulate extracellular effector mechanisms. The present study also provides evidence that neutrophils can internalize parasites by coiling phagocytosis.
Current topics in medicinal chemistry, Jan 2, 2018
Leishmaniasis is a neglected disease caused by protozoan belonging to the Leishmania genus. There... more Leishmaniasis is a neglected disease caused by protozoan belonging to the Leishmania genus. There are at least 16 pathogenic species for humans that are able to cause different clinical forms, such as cutaneous or visceral leishmaniasis. In spite of the different species and clinical forms, the treatment is performed with few drug options that, in most cases, are considered outdated. In addition, patients under classical treatment show serious side effects during drug administration, moreover parasites are able to become resistant to medicines. Thus, it is believed and well accepted that is urgent and necessary to develop new therapeutic options to overpass these concerns about conventional therapy of leishmaniasis. The present review will focus on the efficacy, side effects and action mechanism of classic drugs used in the treatment of leishmaniasis, as well as the importance of traditional knowledge for directing a rational search toward the discovery and characterization of new a...
Veterinary parasitology, Jan 15, 2017
Canine leishmaniosis caused by L. infantum is a severe zoonotic disease. Although macrophages are... more Canine leishmaniosis caused by L. infantum is a severe zoonotic disease. Although macrophages are the definitive host cells, neutrophils are the first cells to encounter the parasite soon after its inoculation in the dermis by the phlebotomine vector. To study the interaction of dog neutrophils and L. infantum promastigotes, blood neutrophils were isolated from healthy donors and the infection was established in vitro. In the majority of the dogs, L. infantum was efficiently phagocytized by neutrophils, and oxidative (superoxide production) and non-oxidative (neutrophil elastase exocytosis) intracellular effector mechanisms were activated, but the release of neutrophil extracellular traps was minimized. Furthermore, promastigotes and culture supernatants induced neutrophil migration, but the prior contact with Leishmania inhibits chemotaxis, which might contribute to neutrophil retention at the inoculation site. Neutrophil-parasite interaction resulted in a decrease in parasite viab...
International journal for parasitology. Drugs and drug resistance, Aug 4, 2017
In the original publication, the eighth author's surname was incorrect. The respective filiation ... more In the original publication, the eighth author's surname was incorrect. The respective filiation is corrected as above. The authors would like to apologise for any inconvenience caused.
Molecular and Cellular Probes, 2016
A loop-mediated isothermal amplification (LAMP) assay was evaluated for the detection of Theileri... more A loop-mediated isothermal amplification (LAMP) assay was evaluated for the detection of Theileria annulata infection in cattle. The results were compared with a real-time PCR used for the quantification of T. annulata parasitaemia. One hundred bovine blood samples from 16 cattle farms were tested with LAMP and real-time PCR, with T. annulata DNA being detected in 66% and 67% of the samples, respectively. The results showed that the LAMP assay detects a parasitaemia as low as 0.00025%, indicating a high analytical sensitivity of LAMP for clinical diagnosis of bovine theileriosis.