Apoptosis of non-parasitized red blood cells in malaria: a putative mechanism involved in the pathogenesis of anaemia

<p>Abstract</p> <p>Background</p> <p>Severe anaemia is a common complication of <it>Plasmodium falciparum </it>malaria in hyperendemic regions. Premature elimination of non-parasitized red blood cells (nRBC) has been considered as one mechanism involved in the genesis of severe malaria anaemia. It has been reported that apoptosis can occur in RBC and, consequently, this cell death process could contribute to anaemia. This study was performed to evaluate the susceptibility of nRBC to apoptosis in a malaria anaemia murine model.</p> <p>Methods</p> <p>Balb/c mice were intraperitonially inoculated with 1 × 10⁶<it>P. yoelii </it>17XL parasitized RBC (pRBC) and, then, parasitaemia and anaemia were monitored. Apoptosis in both pRBC and nRBC was assessed during early and late phases of infection by flow cytometry using Syto 16 and annexin V-PE double staining and forward scatter measurement.</p> <p>Results</p> <p>As expected, experimental infection of Balb/c mice with <it>Plasmodium yoelii </it>17XL parasites was characterized by progressive increase of parasitaemia and acute anaemia, leading to death. Flow cytometry analysis showed that a number of pRBC was in the apoptotic process. It was noteworthy that the increase of nRBC apoptosis levels occurred in the late phase of infection, when anaemia degree was notably accentuated, while no significant alteration was observed in the early phase.</p> <p>Conclusion</p> <p>The increased levels of nRBC apoptosis herein firstly reported, in malaria infection could represent a putative mechanism worsening the severity of malarial anaemia.</p

Evaluation of the genetic polymorphism of Plasmodium falciparum P126 protein (SERA or SERP) and its influence on naturally acquired specific antibody responses in malaria-infected individuals living in the Brazilian Amazon

<p>Abstract</p> <p>Background</p> <p>The <it>Plasmodium falciparum </it>P126 protein is an asexual blood-stage malaria vaccine candidate antigen. Antibodies against P126 are able to inhibit parasite growth <it>in vitro</it>, and a major parasite-inhibitory epitope has been recently mapped to its 47 kDa N-terminal extremity (octamer repeat domain – OR domain). The OR domain basically consists of six octamer units, but variation in the sequence and number of repeat units may appear in different alleles. The aim of the present study was to investigate the polymorphism of P126 N-terminal region OR domain in <it>P. falciparum </it>isolates from two Brazilian malaria endemic areas and its impact on anti-OR naturally acquired antibodies.</p> <p>Methods</p> <p>The study was carried out in two villages, Candeias do Jamari (Rondonia state) and Peixoto de Azevedo (Mato Grosso state), both located in the south-western part of the Amazon region. The repetitive region of the gene encoding the P126 antigen was PCR amplified and sequenced with the di-deoxy chain termination procedure. The antibody response was evaluated by ELISA with the Nt47 synthetic peptide corresponding to the P126 OR-II domain.</p> <p>Results</p> <p>Only two types of OR fragments were identified in the studied areas, one of 175 bp (OR-I) and other of 199 bp (OR-II). A predominance of the OR-II fragment was observed in Candeias do Jamari whereas in Peixoto de Azevedo both fragments OR-I and OR-II were frequent as well as mixed infection (both fragments simultaneously) reported here for the first time. Comparing the DNA sequencing of OR-I and OR-II fragments, there was a high conservation among predicted amino acid sequences of the P126 N-terminal extremity. Data of immune response demonstrated that the OR domain is highly immunogenic in natural conditions of exposure and that the polymorphism of the OR domain does not apparently influence the specific immune response.</p> <p>Conclusion</p> <p>These findings confirm a limited genetic polymorphism of the P126 OR domain in <it>P. falciparum </it>isolates and that this limited genetic polymorphism does not seem to influence the development of a specific humoral immune response to P126 and its immunogenicity in the studied population.</p

Genetic polymorphism of the serine rich antigen N-terminal region in Plasmodium falciparum field isolates from Brazil

In this work we investigated the frequency of polymorphism in exon II of the gene encoding most of the amino-terminal region of the serine rich antigen (SERA) in Plasmodium falciparum field samples. The blood samples were colleted from P. falciparum infected individuals in three areas of the Brazilian Amazon. Two fragments have been characterized by polymerase chain reaction: one of 175 bp corresponding to the repeat region with 5 octamer units and one other of 199 bp related to the 6 repeat octamer units of SERA protein. The 199 bp fragment was the predominant one in all the studied areas. The higher frequency of this fragment has not been described before and could be explained by an immunological selection of the plasmodial population in the infected individuals under study. Since repeat motifs in the amino-terminal region of SERA contain epitopes recognized by parasite-inhibitor antibodies, data reported here suggest that the analysis of the polymorphism of P. falciparum isolates in different geographical areas is a preliminary stage before the final drawing of an universal vaccine against malaria can be reached

Evaluation of allelic forms of the erythrocyte binding antigen 175 (EBA-175) in Plasmodium falciparum field isolates from Brazilian endemic area

<p>Abstract</p> <p>Background</p> <p>The <it>Plasmodium falciparum </it>Erythrocyte Binding Antigen-175 (EBA-175) is an antigen considered to be one of the leading malaria vaccine candidates. EBA-175 mediates sialic acid-dependent binding to glycophorin A on the erythrocytes playing a crucial role during invasion of the <it>P. falciparum </it>in the host cell. Dimorphic allele segments, termed C-fragment and F-fragment, have been found in high endemicity malaria areas and associations between the dimorphism and severe malaria have been described. In this study, the genetic dimorphism of EBA-175 was evaluated in <it>P. falciparum </it>field isolates from Brazilian malaria endemic area.</p> <p>Methods</p> <p>The study was carried out in rural villages situated near Porto Velho, Rondonia State in the Brazilian Amazon in three time points between 1993 and 2008. The allelic dimorphism of the EBA-175 was analysed by Nested PCR.</p> <p>Results</p> <p>The classical allelic dimorphism of the EBA-175 was identified in the studied area. Overall, C-fragment was amplified in a higher frequency than F-fragment. The same was observed in the three time points where C-fragment was observed in a higher frequency than F-fragment. Single infections (one fragment amplified) were more frequent than mixed infection (two fragments amplified).</p> <p>Conclusions</p> <p>These findings confirm the dimorphism of EBA175, since only the two types of fragments were amplified, C-fragment and F-fragment. Also, the results show the remarkable predominance of CAMP allele in the studied area. The comparative analysis in three time points indicates that the allelic dimorphism of the EBA-175 is stable over time.</p

Influence of HLA-DRB1 and HLA-DQB1 Alleles on IgG Antibody Response to the P. vivax MSP-1, MSP-3α and MSP-9 in Individuals from Brazilian Endemic Area

Background: the antibody response generated during malaria infections is of particular interest, since the production of specific IgG antibodies is required for acquisition of clinical immunity. However, variations in antibody responses could result from genetic polymorphism of the HLA class II genes. Given the increasing focus on the development of subunit vaccines, studies of the influence of class II alleles on the immune response in ethnically diverse populations is important, prior to the implementation of vaccine trials.Methods and Findings: in this study, we evaluated the influence of HLA-DRB1* and -DQB1* allelic groups on the naturally acquired humoral response from Brazilian Amazon individuals (n = 276) against P. vivax Merozoite Surface Protein-1 (MSP-1), MSP-3 alpha and MSP-9 recombinant proteins. Our results provide information concerning these three P. vivax antigens, relevant for their role as immunogenic surface proteins and vaccine candidates. Firstly, the studied population was heterogeneous presenting 13 HLA-DRB1* and 5 DQB1* allelic groups with a higher frequency of HLA-DRB1*04 and HLA-DQB1*03. the proteins studied were broadly immunogenic in a naturally exposed population with high frequency of IgG antibodies against PvMSP1-19 (86.7%), PvMSP-3 (77%) and PvMSP-9 (76%). Moreover, HLA-DRB1*04 and HLA-DQB1*03 alleles were associated with a higher frequency of IgG immune responses against five out of nine antigens tested, while HLA-DRB1* 01 was associated with a high frequency of non-responders to repetitive regions of PvMSP-9, and the DRB1*16 allelic group with the low frequency of responders to PvMSP3 full length recombinant protein.Conclusions: HLA-DRB1*04 alleles were associated with high frequency of antibody responses to five out of nine recombinant proteins tested in Rondonia State, Brazil. These features could increase the success rate of future clinical trials based on these vaccine candidates.Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Yerkes National Primate Research Center BaseNational Center for Research Resources of the National Institutes of HealthNIHCoordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Inst Oswaldo Cruz, Lab Immunoparasitol, BR-20001 Rio de Janeiro, BrazilOswaldo Cruz Fdn Fiocruz, Ctr Technol Dev Hlth CDTS, Rio de Janeiro, BrazilInst Oswaldo Cruz, Lab Simulideos & Oncocercose, BR-20001 Rio de Janeiro, BrazilEmory Univ, Emory Vaccine Ctr, Atlanta, GA 30322 USAUniv Estado Rio de Janeiro, Histocompatibil & Cryopreservat Lab, Rio de Janeiro, BrazilUniversidade Federal de São Paulo, Ctr Terapia Celular & Mol CTCMol, Escola Paulista Med, São Paulo, BrazilEmory Univ, Sch Med, Div Infect Dis, Atlanta, GA USACDC Natl Ctr Infect Dis, Div Parasit Dis, Atlanta, GA USAUniversidade Federal de São Paulo, Ctr Terapia Celular & Mol CTCMol, Escola Paulista Med, São Paulo, BrazilFAPESP: 2009/15132-4Yerkes National Primate Research Center Base: RR00165NIH: RO1 AI0555994Web of Scienc

Ocular Onchocerciasis in the Yanomami Communities from Brazilian Amazon: Effects on Intraocular Pressure

Made available in DSpace on 2015-06-22T12:26:38Z (GMT). No. of bitstreams: 2 license.txt: 1914 bytes, checksum: 7d48279ffeed55da8dfe2f8e81f3b81f (MD5) veronica_silvaetal_IOC_2014.pdf: 440453 bytes, checksum: dc431412e64503ae497c091ec7f63fc4 (MD5) Previous issue date: 2014Universidade Federal Fluminense. Serviço de Oftalmologia. Niterói, RJ, Brasil.Universidade Federal Fluminense. Serviço de Oftalmologia. Niterói, RJ, Brasil.Fundação Oswaldo Cruz. Instituto Oswaldo Cruz. Laboratório de Referência Nacional de Simulídeos e Oncocercose. Rio de Janeiro, RJ, Brasil.Fundação Oswaldo Cruz. Instituto Oswaldo Cruz. Laboratório de Referência Nacional de Simulídeos e Oncocercose. Rio de Janeiro, RJ, Brasil.Fundação Oswaldo Cruz. Instituto Oswaldo Cruz. Laboratório de Referência Nacional de Simulídeos e Oncocercose. Rio de Janeiro, RJ, Brasil.Fundação Oswaldo Cruz. Instituto Oswaldo Cruz. Laboratório de Referência Nacional de Simulídeos e Oncocercose. Rio de Janeiro, RJ, Brasil.To determine the influence of onchocercal eye disease on the intraocular pressure of the Yanomami Tribe Aratha-u´ of Roraima State, Brazil, considered endemic for onchocerciasis, a total of 86 patients were submitted to an ophthalmologic exam that included external examination, slit lamp examination, intraocular pressure measurement, and a fundus ophthalmoscope examination. A high prevalence of onchocerciasis-related eye lesions was encountered in 68.6% of the patients. Punctate keratitis and microfilariae in the anterior chamber were found in ~28%. The mean of intraocular eye pressure found was 10.47 mm of Hg

Malaria-Cutaneous Leishmaniasis Co-infection: Influence on Disease Outcomes and Immune Response

Submitted by Sandra Infurna ([email protected]) on 2016-12-20T10:44:21Z No. of bitstreams: 1 raquel_pinna_etal_IOC_2016.pdf: 2383252 bytes, checksum: 50aaccd9cf457d68842333845f6cd960 (MD5)Approved for entry into archive by Sandra Infurna ([email protected]) on 2016-12-20T10:57:31Z (GMT) No. of bitstreams: 1 raquel_pinna_etal_IOC_2016.pdf: 2383252 bytes, checksum: 50aaccd9cf457d68842333845f6cd960 (MD5)Made available in DSpace on 2016-12-20T10:57:31Z (GMT). No. of bitstreams: 1 raquel_pinna_etal_IOC_2016.pdf: 2383252 bytes, checksum: 50aaccd9cf457d68842333845f6cd960 (MD5) Previous issue date: 2016Fundação Oswaldo Cruz. Instituto Oswaldo Cruz. Laboratório de Simulídeos, Oncocercose e Infecções Simpáticas: Mansonerlose e Malária. Rio de Janeiro, RJ, Brasil.Fundação Oswaldo Cruz. Instituto Oswaldo Cruz. Laboratório de Pesquisa sobre o Timo. Rio de Janeiro, RJ, Brasil.Fundação Oswaldo Cruz. Instituto Oswaldo Cruz. Laboratório de Simulídeos, Oncocercose e Infecções Simpáticas: Mansonerlose e Malária. Rio de Janeiro, RJ, Brasil.Fundação Oswaldo Cruz. Instituto Oswaldo Cruz. Laboratório de Imunoparasitologia. Rio de Janeiro, RJ, Brasil.Fundação Oswaldo Cruz. Instituto Oswaldo Cruz. Laboratório de Pesquisa sobre o Timo. Rio de Janeiro, RJ, Brasil.Fundação Oswaldo Cruz. Instituto Oswaldo Cruz. Laboratório de Imunoparasitologia. Rio de Janeiro, RJ, Brasil.Fundação Oswaldo Cruz. Instituto Oswaldo Cruz. Laboratório de Simulídeos, Oncocercose e Infecções Simpáticas: Mansonerlose e Malária. Rio de Janeiro, RJ, Brasil.Malaria and Cutaneous Leishmaniasis (CL) are co-endemic throughout large regions in tropical countries and co-infection may impact the evolution of host-parasite interactions. In the present study, we evaluate Malaria/Leishmaniasis disease outcome, Th1/Th2 cytokine levels and the CD4 and CD8 T-cell profiles in a co-infection murine model (BALB/c) of Plasmodium yoelii 17XNL (Py) and Leishmania amazonensis (La) or L. braziliensis (Lb). Malaria parasitaemia was assessed through blood strains stained with Giemsa. Leishmania lesions were monitored with a digital caliper and parasite loads determined by limiting-dilution assay. Serum levels of IFN-γ, TNF, IL-2, IL-4, IL-6, IL-10, and IL-17 were determined using multiplexed bead assay and expression of CD3, CD4, and CD8 T-cells markers were determined by Flow Cytometry in the thymus, spleens and lymph nodes. Parasitaemia in Lb+Py co-infected group was lower than in Py single-infected group, suggesting a protective effect of Lb co-infection in Malaria progression. In contrast, La+Py co-infection increased parasitaemia, patent infection and induced mortality in non-lethal Malaria infection. Regarding Leishmaniasis, Lb+Py co-infected group presented smaller lesions and less ulceration than Lb single-infected animals. In contrast, La+Py co-infected group presented only a transitory delay on the development of lesions when compared to La single-infected mice. Decreased levels of IFN-γ, TNF, IL-6, and IL-10 were observed in the serum of co-infected groups, demonstrating a modulation of Malaria immune response by Leishmania co-infections. We observed an intense thymic atrophy in Py single-infected and co-infected groups, which recovered earlier in co-infected animals. The CD4 and CD8 T cell profiles in thymus, spleens and lymph nodes did not differ between Py single and co-infected groups, except for a decrease in CD4(+)CD8(+) T cells which also increased faster in co-infected mice. Our results suggest that Py and Leishmania co-infection may change disease outcome. Interestingly Malaria outcome can be altered according to the Leishmania specie involved. Alternatively Malaria infection reduced the severity or delayed the onset of leishmanial lesions. These alterations in Malaria and CL development seem to be closely related with changes in the immune response as demonstrated by alteration in serum cytokine levels and thymus/spleens T cell phenotypes dynamics during infection

Malaria diagnosis: standardization of a polymerase chain reaction for the detection of Plasmodium falciparum parasites in individuals with low-grade parasitemia

This work was supported by the Science and Technology for Development Program of the Commission of the European Communities and by the Brazilian National Research Council (CNPq). Maria de Fátima Ferreira-da-Cruz is the recipient of a CNPq fellowship (Pesq 302325/84–0 NV).Universidade Federal do Rio de Janeiro. Department of Biophysics. Rio de Janeiro, RJ, Brasil.Fundação Oswaldo Cruz. Instituto Oswaldo Cruz. Department of Immunology. World Health Organization Collaborating Center for Research and Training in the Immunology of Parasitic Diseases, Rio de Janeiro, RJ, Brazil.Fundação Oswaldo Cruz. Instituto Oswaldo Cruz. Department of Immunology. World Health Organization Collaborating Center for Research and Training in the Immunology of Parasitic Diseases, Rio de Janeiro, RJ, Brazil.Fundação Oswaldo Cruz. Instituto Oswaldo Cruz. Department of Immunology. World Health Organization Collaborating Center for Research and Training in the Immunology of Parasitic Diseases, Rio de Janeiro, RJ, Brazil.Instituto de Medicina Tropical. Manaus, AM, Brazil.Ministério da Saúde. Fundação Nacional de Saúde. Instituto Evandro Chagas. Belém, PA, Brasil.Institut Pasteur de Paris. FranceFundação Oswaldo Cruz. Instituto Oswaldo Cruz. Department of Immunology. World Health Organization Collaborating Center for Research and Training in the Immunology of Parasitic Diseases, Rio de Janeiro, RJ, Brazil.In Brazil, no study has been done concerning the detection of malaria parasites by polymerase chain reaction (PCR) related to the diagnosis of Plasmodium falciparum malaria. In the present report we describe a highly sensitive methodology for malaria diagnosis using a nested PCR method based on amplification of the p126 P. falciparum gene detected by simple ethidium bromide staining. The P. falciparum Palo Alto strain (culture samples) was serially diluted in blood from an uninfected donor to a final level of parasitemia corresponding to 10–8% and was processed for PCR amplification. In each of these dilutions a parasitological examination was performed to compare the sensitivity with that of PCR amplification. Blood samples (field samples) were obtained from 51 malarious patients with positive thick blood smears (TBS) who were living in endemic regions of the Brazilian Amazon. They corresponded to 42 P. falciparum and 9 P. vivax cases, with parasitemia levels ranging from only 16 to 20,200 parasites/µl for P. falciparum disease and from 114 to 11,000 parasites/µl for P. vivax malaria. We demonstrate that the use of nested PCR allows the detection of 0.005 parasites/µl without the use of radioactive material. The use of a 1-ml sample volume and the organic DNA extraction method should be suitable in blood banks and for the evaluation of patients during and after drug treatment