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

Neotropical primate models for malaria research: 25 years of collaboration between Laboratory of Malaria Research (IOC, Fiocruz) and Centro Nacional de Primatas (IEC, SVS)

Fundação Oswaldo Cruz. Instituto Oswaldo Cruz. Laboratório de Pesquisa em Malária. Rio de Janeiro, RJ, Brasil / Fundação Oswaldo Cruz. Centro de Pesquisa, Diagnóstico e Treinamento em Malária. Rio de Janeiro, RJ, Brasil.Fundação Oswaldo Cruz. Instituto Oswaldo Cruz. Laboratório de Pesquisa em Malária. Rio de Janeiro, RJ, Brasil / Fundação Oswaldo Cruz. Centro de Pesquisa, Diagnóstico e Treinamento em Malária. Rio de Janeiro, RJ, Brasil.Fundação Oswaldo Cruz. Instituto Oswaldo Cruz. Laboratório de Pesquisa em Malária. Rio de Janeiro, RJ, Brasil / Fundação Oswaldo Cruz. Centro de Pesquisa, Diagnóstico e Treinamento em Malária. Rio de Janeiro, RJ, Brasil.Fundação Oswaldo Cruz. Instituto Oswaldo Cruz. Laboratório de Pesquisa em Malária. Rio de Janeiro, RJ, Brasil / Fundação Oswaldo Cruz. Centro de Pesquisa, Diagnóstico e Treinamento em Malária. Rio de Janeiro, RJ, Brasil.Fundação Oswaldo Cruz. Instituto Oswaldo Cruz. Laboratório de Pesquisa em Malária. Rio de Janeiro, RJ, Brasil / Fundação Oswaldo Cruz. Centro de Pesquisa, Diagnóstico e Treinamento em Malária. Rio de Janeiro, RJ, Brasil.Fundação Oswaldo Cruz. Instituto Oswaldo Cruz. Laboratório de Pesquisa em Malária. Rio de Janeiro, RJ, Brasil / Fundação Oswaldo Cruz. Centro de Pesquisa, Diagnóstico e Treinamento em Malária. Rio de Janeiro, RJ, Brasil.Ministério da Saúde. Secretaria de Vigilância em Saúde. Instituto Evandro Chagas. Centro Nacional de Primatas. Ananindeua, PA, Brasil.Ministério da Saúde. Secretaria de Vigilância em Saúde. Instituto Evandro Chagas. Centro Nacional de Primatas. Ananindeua, PA, Brasil.Fundação Oswaldo Cruz. Instituto Oswaldo Cruz. Laboratório de Pesquisa em Malária. Rio de Janeiro, RJ, Brasil / Fundação Oswaldo Cruz. Centro de Pesquisa, Diagnóstico e Treinamento em Malária. Rio de Janeiro, RJ, Brasil.Fundação Oswaldo Cruz. Instituto Oswaldo Cruz. Laboratório de Pesquisa em Malária. Rio de Janeiro, RJ, Brasil / Fundação Oswaldo Cruz. Centro de Pesquisa, Diagnóstico e Treinamento em Malária. Rio de Janeiro, RJ, Brasil.A malária continua sendo um dos principais problemas globais de saúde pública, sendo responsável pela morte de 409.000 pessoas anualmente, principalmente devido à infecção por Plasmodium falciparum. Assim, o desenvolvimento de uma vacina tem sido uma das prioridades de pesquisa para o enfrentamento desse problema. Não existe vacina licenciada contra a malária e, embora mais de 30 antígenos tenham sido identificados como candidatos vacinais, nenhum deles gerou uma perspectiva sólida de que uma vacina possa estar disponível nos próximos anos. Torna-se fundamental a pesquisa de candidatos vacinais mais imunogênicos, eficazes e seguros. Os primatas neotropicais dos gêneros Saimiri e Aotus são os modelos recomendados para estudos experimentais em malária, visto que podem ser infectados por plasmódios humanos. O Laboratório de Pesquisa em Malária (LabMal) da Fundação Oswaldo Cruz estuda os mecanismos de defesa e doença na malária e utiliza os modelos Saimiri e Aotus para a avaliação pré-clínica de antígenos candidatos à vacina e estudos de mecanismos de aquisição de imunidade e fisiopatogenia da malária. Para a realização dos estudos, o LabMal estabeleceu uma parceria com o Centro Nacional de Primatas (CENP) do Instituto Evandro Chagas, que resultou na ampliação das colônias de Saimiri sciureus, colocando o CENP entre as raras instituições no mundo que dispõem desse recurso para pesquisa. O presente trabalho é um retrospecto dos resultados obtidos durante 25 anos de parceria entre o LabMal e o CENP na utilização de primatas Saimiri e Aotus como modelos de estudo para pesquisa e desenvolvimento de uma vacina antimalárica

SHORT COMMUNICATION - 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

Naturally acquired antibody response to a <i>Plasmodium falciparum</i> chimeric vaccine candidate GMZ2.6c and its components (MSP-3, GLURP, and Pfs48/45) in individuals living in Brazilian malaria-endemic areas

BACKGROUND: The GMZ2.6c malaria vaccine candidate is a multi-stage Plasmodium falciparum chimeric protein which contains a fragment of the sexual-stage Pfs48/45-6C protein genetically fused to GMZ2, a fusion protein of GLURP and MSP-3, that has been shown to be well tolerated, safe and immunogenic in clinical trials performed in a malaria-endemic area of Africa. However, there is no data available on the antigenicity or immunogenicity of GMZ2.6c in humans. Considering that circulating parasites can be genetically distinct in different malaria-endemic areas and that host genetic factors can influence the immune response to vaccine antigens, it is important to verify the antigenicity, immunogenicity and the possibility of associated protection in individuals living in malaria-endemic areas with different epidemiological scenarios. Herein, the profile of antibody response against GMZ2.6c and its components (MSP-3, GLURP and Pfs48/45) in residents of the Brazilian Amazon naturally exposed to malaria, in areas with different levels of transmission, was evaluated. METHODS: This study was performed using serum samples from 352 individuals from Cruzeiro do Sul and Mâncio Lima, in the state of Acre, and Guajará, in the state of Amazonas. Specific IgG, IgM, IgA and IgE antibodies and IgG subclasses were detected by Enzyme-Linked Immunosorbent Assay. RESULTS: The results showed that GMZ2.6c protein was widely recognized by naturally acquired antibodies from individuals of the Brazilian endemic areas with different levels of transmission. The higher prevalence of individuals with antibodies against GMZ2.6c when compared to its individual components may suggest an additive effect of GLURP, MSP-3, and Pfs48/45 when inserted in a same construct. Furthermore, naturally malaria-exposed individuals predominantly had IgG1 and IgG3 cytophilic anti-GMZ2.6c antibodies, an important fact considering that the acquisition of anti-malaria protective immunity results from a delicate balance between cytophilic/non-cytophilic antibodies. Interestingly, anti-GMZ2.6c antibodies seem to increase with exposure to malaria infection and may contribute to parasite immunity. CONCLUSIONS: The data showed that GMZ2.6c protein is widely recognized by naturally acquired antibodies from individuals living in malaria-endemic areas in Brazil and that these may contribute to parasite immunity. These data highlight the importance of GMZ2.6c as a candidate for an anti-malarial vaccine. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1186/s12936-021-04020-6

Chloroquine and mefloquine resistance profiles are not related to the circumsporozoite protein (CSP) VK210 subtypes in field isolates of Plasmodium vivax from Manaus, Brazilian Amazon

Submitted by Sandra Infurna ([email protected]) on 2019-11-06T14:25:01Z No. of bitstreams: 1 LilainR_Riccio_etal_IOC_2019.pdf: 3741301 bytes, checksum: 023e3ad34e0b32135430c08592365d4f (MD5)Approved for entry into archive by Sandra Infurna ([email protected]) on 2019-11-06T14:38:44Z (GMT) No. of bitstreams: 1 LilainR_Riccio_etal_IOC_2019.pdf: 3741301 bytes, checksum: 023e3ad34e0b32135430c08592365d4f (MD5)Made available in DSpace on 2019-11-06T14:38:44Z (GMT). No. of bitstreams: 1 LilainR_Riccio_etal_IOC_2019.pdf: 3741301 bytes, checksum: 023e3ad34e0b32135430c08592365d4f (MD5) Previous issue date: 2019Fundação Oswaldo Cruz. Instituto Oswaldo Cruz. Laboratório de Pesquisa em Malária. Rio de Janeiro, RJ, Brasil / Fundação Oswaldo Cruz. Instituto Oswaldo Cruz. Centro de Pesquisa, Diagnóstico e Treinamento em Malária. Rio de Janeiro, RJ, Brasil.Fundação Oswaldo Cruz. Instituto Oswaldo Cruz. Laboratório de Pesquisa em Malária. Rio de Janeiro, RJ, Brasil / Fundação Oswaldo Cruz. Instituto Oswaldo Cruz. Centro de Pesquisa, Diagnóstico e Treinamento em Malária. Rio de Janeiro, RJ, Brasil.Fundação Oswaldo Cruz. Instituto Oswaldo Cruz. Laboratório de Pesquisa em Malária. Rio de Janeiro, RJ, Brasil / Fundação Oswaldo Cruz. Instituto Oswaldo Cruz. Centro de Pesquisa, Diagnóstico e Treinamento em Malária. Rio de Janeiro, RJ, Brasil.Fundação Oswaldo Cruz. Instituto Oswaldo Cruz. Laboratório de Pesquisa em Malária. Rio de Janeiro, RJ, Brasil / Fundação Oswaldo Cruz. Instituto Oswaldo Cruz. Centro de Pesquisa, Diagnóstico e Treinamento em Malária. Rio de Janeiro, RJ, Brasil.Fundação Oswaldo Cruz. Instituto Oswaldo Cruz. Laboratório de Pesquisa em Malária. Rio de Janeiro, RJ, Brasil / Fundação Oswaldo Cruz. Instituto Oswaldo Cruz. Centro de Pesquisa, Diagnóstico e Treinamento em Malária. Rio de Janeiro, RJ, Brasil.Fundação Oswaldo Cruz. Instituto Oswaldo Cruz. Laboratório de Pesquisa em Malária. Rio de Janeiro, RJ, Brasil / Fundação Oswaldo Cruz. Instituto Oswaldo Cruz. Centro de Pesquisa, Diagnóstico e Treinamento em 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 em Malária. Rio de Janeiro, RJ, Brasil / Fundação Oswaldo Cruz. Instituto Oswaldo Cruz. Centro de Pesquisa, Diagnóstico e Treinamento em Malária. Rio de Janeiro, RJ, Brasil.Universidade de Campinas. Departamento de Genética, Evolução e Bioagentes. Laboratório de Doenças Tropicais, Campinas, SP, Brasil.Universidade Federal de Sergipe. Centro de Ciências Biológicas e da Saúde. Departamento de Biologia. Aracaju, SE, Brasil.Universidade Federal Fluminense. Instituto Biomédico. Departamento de Microbiologia e Parasitologia. Niterói, RJ, Brasil.Fundação Oswaldo Cruz. Instituto Oswaldo Cruz. Laboratório de Imunoparasitologia. Rio de Janeiro, RJ, Brasil.Fundação Oswaldo Cruz. Instituto Oswaldo Cruz. Laboratório de Imunologia Clínica. Rio de Janeiro, RJ, Brasil.Fundação Oswaldo Cruz. Instituto Oswaldo Cruz. Laboratório de Pesquisa em Malária. Rio de Janeiro, RJ, Brasil / Fundação Oswaldo Cruz. Instituto Oswaldo Cruz. Centro de Pesquisa, Diagnóstico e Treinamento em Malária. Rio de Janeiro, RJ, Brasil.Fundação Oswaldo Cruz. Instituto Oswaldo Cruz. Laboratório de Pesquisa em Malária. Rio de Janeiro, RJ, Brasil / Fundação Oswaldo Cruz. Instituto Oswaldo Cruz. Centro de Pesquisa, Diagnóstico e Treinamento em Malária. Rio de Janeiro, RJ, Brasil.BACKGROUND The central repetitive region (CRR) of the Plasmodium vivax circumsporozoite surface protein (CSP) is composed of a repetitive sequence that is characterised by three variants: VK210, VK247 and P. vivax-like. The most important challenge in the treatment of P. vivax infection is the possibility of differential response based on the parasite genotype. OBJECTIVES To characterise the CSP variants in P. vivax isolates from individuals residing in a malaria-endemic region in Brazil and to profile these variants based on sensitivity to chloroquine and mefloquine. METHODS The CSP variants were determined by sequencing and the sensitivity of the P. vivax isolates to chloroquine and mefloquine was determined by Deli-test. FINDINGS Although five different allele sizes were amplified, the sequencing results showed that all of the isolates belonged to the VK210 variant. However, we observed substantial genetic diversity in the CRR, resulting in the identification of 10 different VK210 subtypes. The frequency of isolates that were resistant to chloroquine and mefloquine was 11.8 and 23.8%, respectively. However, we did not observe any difference in the frequency of the resistant isolates belonging to the VK210 subtypes. MAIN CONCLUSION The VK210 variant is the most frequently observed in the studied region and there is significant genetic variability in the CRR of the P. vivax CSP. Moreover, the antimalarial drug sensitivity profiles of the isolates does not seem to be related to the VK210 subtypes

Antibodies against the Plasmodium falciparum glutamate-rich protein from naturally exposed individuals living in a Brazilian malaria-endemic area can inhibit in vitro parasite growth

The glutamate-rich protein (GLURP) is an exoantigen expressed in all stages of the Plasmodium falciparum life cycle in humans. Anti-GLURP antibodies can inhibit parasite growth in the presence of monocytes via antibody-dependent cellular inhibition (ADCI), and a major parasite-inhibitory region has been found in the N-terminal R0 region of the protein. Herein, we describe the antiplasmodial activity of anti-GLURP antibodies present in the sera from individuals naturally exposed to malaria in a Brazilian malaria-endemic area. The anti-R0 antibodies showed a potent inhibitory effect on the growth of P. falciparum in vitro, both in the presence (ADCI) and absence (GI) of monocytes. The inhibitory effect on parasite growth was comparable to the effect of IgGs purified from pooled sera from hyperimmune African individuals. Interestingly, in the ADCI test, higher levels of tumour necrosis factor alpha (TNF-&#945;) were observed in the supernatant from cultures with higher parasitemias. Our data suggest that the antibody response induced by GLURP-R0 in naturally exposed individuals may have an important role in controlling parasitemia because these antibodies are able to inhibit the in vitro growth of P. falciparum with or without the cooperation from monocytes. Our results also indicate that TNF-&#945; may not be relevant for the inhibitory effect on P. falciparum in vitro growth

B-Cell Epitope Mapping of the <i>Plasmodium falciparum</i> Malaria Vaccine Candidate GMZ2.6c in a Naturally Exposed Population of the Brazilian Amazon

The GMZ2.6c malaria vaccine candidate is a multi-stage P. falciparum chimeric protein that contains a fragment of the sexual-stage Pfs48/45-6C protein genetically fused to GMZ2, an asexual-stage vaccine construction consisting of the N-terminal region of the glutamate-rich protein (GLURP) and the C-terminal region of the merozoite surface protein-3 (MSP-3). Previous studies showed that GMZ2.6c is widely recognized by antibodies from Brazilian exposed individuals and that its components are immunogenic in natural infection by P. falciparum. In addition, anti-GMZ2.6c antibodies increase with exposure to infection and may contribute to parasite immunity. Therefore, identifying epitopes of proteins recognized by antibodies may be an important tool for understanding protective immunity. Herein, we identify and validate the B-cell epitopes of GMZ2.6c as immunogenic and immunodominant in individuals exposed to malaria living in endemic areas of the Brazilian Amazon. Specific IgG antibodies and subclasses against MSP-3, GLURP, and Pfs48/45 epitopes were detected by ELISA using synthetic peptides corresponding to B-cell epitopes previously described for MSP-3 and GLURP or identified by BepiPred for Pfs48/45. The results showed that the immunodominant epitopes were P11 from GLURP and MSP-3c and DG210 from MSP-3. The IgG1 and IgG3 subclasses were preferentially induced against these epitopes, supporting previous studies that these proteins are targets for cytophilic antibodies, important for the acquisition of protective immunity. Most individuals presented detectable IgG antibodies against Pfs48/45a and/or Pfs48/45b, validating the prediction of linear B-cell epitopes. The higher frequency and antibody levels against different epitopes from GLURP, MSP-3, and Pfs48/45 provide additional information that may suggest the relevance of GMZ2.6c as a multi-stage malaria vaccine candidate

Antibodies against the Plasmodium falciparum glutamate-rich protein from naturally exposed individuals living in a Brazilian malaria-endemic area can inhibit in vitro parasite growth

The glutamate-rich protein (GLURP) is an exoantigen expressed in all stages of the Plasmodium falciparum life cycle in humans. Anti-GLURP antibodies can inhibit parasite growth in the presence of monocytes via antibody-dependent cellular inhibition (ADCI), and a major parasite-inhibitory region has been found in the N-terminal R0 region of the protein. Herein, we describe the antiplasmodial activity of anti-GLURP antibodies present in the sera from individuals naturally exposed to malaria in a Brazilian malaria-endemic area. The anti-R0 antibodies showed a potent inhibitory effect on the growth of P. falciparum in vitro, both in the presence (ADCI) and absence (GI) of monocytes. The inhibitory effect on parasite growth was comparable to the effect of IgGs purified from pooled sera from hyperimmune African individuals. Interestingly, in the ADCI test, higher levels of tumour necrosis factor alpha (TNF-α) were observed in the supernatant from cultures with higher parasitemias. Our data suggest that the antibody response induced by GLURP-R0 in naturally exposed individuals may have an important role in controlling parasitemia because these antibodies are able to inhibit the in vitro growth of P. falciparum with or without the cooperation from monocytes. Our results also indicate that TNF-α may not be relevant for the inhibitory effect on P. falciparum in vitro growth