Immunity to malaria using the rodent malaria parasite Plasmodium chabaudi chabaudi AS as a model of the human malaria Plasmodium falciparum

The role of IFN in acquisition of immunity against erythrocyte forms of P.c. chabaudi AS was studied. Inbred NIH mice given the construct 7 days before malaria infection, showed a significant delay in the onset and in the level of the recrudescent parasitaemia in comparison with controls. No differences, however, were observed in the recrudescent parasitaemia between the groups. NIH mice infected with malaria 3 days after or on the same day as the administration of the IFN construct, showed a primary peak of infection similar to controls, but the resolution of this patent parasitaemia occurred 1 or 2 days earlier in the experimental mice when compared with controls. In the same experiment, mice given the construct 10 days before malaria infection had a similar course of infection as controls. Simultaneous inoculation with two S. typhimurium constructs: IFN and TNF, 8 days before malaria infection resulted in a course of parasitaemia similar to that observed in mice given the IFN construct alone. On the other hand, inoculation of 'susceptible' inbred A/J mice with S. typhimurium/IFN 3 or 8 days before malaria infection had no effect on the course of the parasitaemia when compared with controls. The immune mechanisms involved in the better control of the malaria infection of NIH mice given S. typhimurium/ IFN, seem to be independent of nitric oxide (NO) production, since increased levels of the molecule were demonstrable around the peak of the primary parasitaemia in control groups but not in experimental mice. In the latter basal levels of serum NO were observed from the period after the S. typhimurium/ IFN inoculation until up to three days after the peak of the parasitaemia

Alta frecuencia de mutaciones puntuales en pfcrt de Plasmodium falciparum y emergencia de nuevos haplotipos mutantes en Colombia

Introduction. Studies on the molecular epidemiology of antimalarial resistance constitute a useful tool to understand the events underlying treatment failure and resistance in falciparum malaria in Colombia. Several authors have reported on the efficacy of some molecular markers to predict drug resistance in Plasmodium falciparum. The P. falciparum pfcrt gene has been widely characterized in this context. Objective. The frequency of pfcrt gene mutations in P. falciparum were associated with treatment failure to the antimalarials chloroquine, mefloquine, amodiaquine and sulfadoxine/ pyrimethamine. Materials and methods. A representative sample of 172 patients with non-complicated falciparum malaria was selected from two highly malaria-endemic areas of northeastern Colombia, the Turbo and Bajo Cauca regions. These patients were assessed for treatment response together with the status of codons 72, 74, 75 and 76 in the pfcrt gene using a PCRRFLP approach. Results. A high frequency of treatment failure to chloroquine (82%) and to amodiaquine (29%) was confirmed, whereas mefloquine and combined therapy remained effective. The presence of the T76 mutation in pfcrt was confirmed in all samples. The most common haplotype was CMNT (67%). Conclusions. No significant association was confirmed between specific haplotypes and the treatment response in any of the treatment groups. Two haplotypes, SMET and SMNT, were reported for the first time in Colombia. Twelve percent of the samples carried both mixed mutant and wild-type alleles.Introducción. Los estudios en epidemiología molecular de resistencia a antipalúdicos constituyen una herramienta útil para comprender eventos involucrados en la falla al tratamiento y la resistencia en paludismo por Plasmodium falciparum en Colombia. Diversos autores han informado sobre la eficacia de algunos marcadores moleculares para predecir resistencia a fármacos en P. falciparum y el gen pfcrt ha sido ampliamente caracterizado en este contexto. Objetivo. Estudiar la frecuencia de mutaciones en el gen pfcrt de P. falciparum y su asociación con falla al tratamiento con cloroquina, mefloquina, amodiaquina y sulfadoxina/pirimetamina, en dos regiones muy endémicas para paludismo del noroeste de Colombia: Turbo y Bajo Cauca. Materiales y métodos. Una muestra representativa de pacientes con paludismo por P. falciparum no complicado fue seleccionada de cada localidad para la evaluación de la respuesta al tratamiento y la determinación del estado de los codones 72, 74, 75 y 76 de pfcrt, usando una aproximación basada en PCR-RFLP. Resultados. Se confirmó una alta frecuencia de falla al tratamiento con cloroquina (82%) y amodiaquina (29%), mientras que la mefloquina y la terapia combinada fueron eficaces para eliminar la infección. La presencia de la mutación T76 en pfcrt fue confirmada en todas las 172 muestras; el haplotipo más común fue CMNT (67%). Conclusiones. No se observó asociación significativa entre un haplotipo particular y la respuesta al tratamiento en cualquiera de los grupos. Se reporta por primera vez en Colombia la presencia de dos haplotipos, SMET y SMNT; se encontraron alelos mutantes y silvestres simultáneamente en 12% de las muestras

High IFN-gamma and TNF production by peripheral NK cells of Colombian patients with different clinical presentation of Plasmodium falciparum

<p>Abstract</p> <p>Background</p> <p>In Colombia<it>, Plasmodium falciparum </it>infection rarely results in severe disease or mortality compared to infections in African populations. During natural infection NK cells exhibit a cytolytic effect and regulate dendritic cells, macrophages, neutrophils as well as affect antigen specific T and B cell responses. To characterize the NK cells in <it>P. falciparum </it>infected patients of a highly endemic region of Colombia, the degree of NK proliferation and production of IFN gamma and TNF production in these cells were explored.</p> <p>Methods</p> <p>Seventeen patients with acute and three with severe <it>P. falciparum </it>malaria patients from the Northwest region of the country were recruited in the study. In addition, 20 healthy controls were included: 10 from Medellin (no-transmission area) and 10 from the Uraba region (a malaria endemic area). Immunophenotypic analysis of peripheral mononuclear cells was performed by FACS to detect total number of NK cells, subtypes and intracellular IFNγ and TNF production by NK cells in the different patient groups.</p> <p>Results</p> <p>The total mean CD56⁺/CD3^-NK cell proportions in acute and severe malaria subjects were 9.14% (7.15%CD56^dim, 2.01%CD56^bright) and 19.62% (16.05%CD56^dim, 3.58%CD56^bright), respectively, in contrast to healthy controls from endemic (total mean CD56⁺/CD3^-1.2%) and non-endemic area (total mean CD56⁺/CD3^-0.67%). Analysis of basal IFNγ and TNF levels confirmed the CD56^brightNK population as the main cytokine producer (<it>p </it>< 0.0001) in the groups affected with malaria, with the CD56^dimNK cell exhibiting the highest potential of TNF production after stimulus in the acute malaria group.</p> <p>Conclusions</p> <p>The results confirm the important role of not only CD56^brightbut also of CD56^dimNK cell populations as producers of the two cytokines in malaria patients in Colombia.</p

Public Communication of Science: The Experience of the Rio Grande Valley Alzheimer’s Disease Resource Center for Minority Aging Research

Introduction: There are multiple models of public communication of science. Some models focus on communication within the science community, while others involve public participation. At the Rio Grande Valley AD-RCMAR, we hope to implement a public outreach program to aid in the dissemination of accurate information regarding Alzheimer’s disease and related dementias. Objective: The purpose of this project was to identify behavioral change models that will allow the RGV AD-RCMAR to increase awareness and engagement of brain aging, including Alzheimer’s disease, within the Rio Grande Valley. Methods: A literature review was conducted to identify models of behavioral change that will assist the center in the dissemination of science. Public communication models were narrowed down to models that aligned with the goals of the center. Results: We identified four models and found that the Precaution Adoption Process Model (PAPM) and the Tailored Health Communication (THC) model were grounded in behavioral change and would best fit the needs of the AD-RCMAR. We integrated these models by building profiles to highlight Latinx researchers and a database of neuroscience seminars that will aid in the increased awareness and recruitment of individuals on topics that are tailored to their interests. Discussion: In order to make an impact, we must consider human behavior. By integrating the PAPM and THC models, individuals will have access to topics that are tailored to what they are searching for, which will result in raised awareness. Conclusion: These models will allow us to raise engagement and awareness in the RGV and support the recruitment of participants in research. There are some factors to consider prior to implementing these models including Hispanic values and their effect on involvement and communication of scientific information. Then, we will begin to question the changes in the levels of engagement and action

Efectos de la malaria gestacional por Plasmodium vivax sobre el estado clínico e inmune en gestantes del Noroccidente de Colombia.

Objetive: The study explored the effects of Plasmodium vivax infection on the balance of pro- versus anti- inflammatory cytokines and chemokines and their relationship with some clinical and epidemiology outcomes. Methods: Thirty-five pregnant women were recruited. Of these, 15 subjects had malaria at delivery (GM+), and 20 had no exposition to infection throughout the pregnancy (GM-) and at delivery. Epidemiological and clinical data were recorded after reviewing the clinical records. At delivery, whole blood from the mother as well as placental tissue was collected. Diagnosis of infection was performed by thick smear and a polymerase chain reaction (PCR). Expression of pro-inflammatory and anti-inflammatory cytokines and chemokines was measured by a real time PCR. Results: The clinical and epidemiological variables explored were similar in both groups, with the exception of gestational age. When comparing the GM+ group with the GM- group, it is clear that although the differences generally are not significant, pro- inflammatory cytokines are elevated in both maternal blood and placental; anti-inflammatory ones are elevated in the mother and reduced in the placenta, and the chemokines are reduced in both compartments, except for MCP-1 which is elevated in all. Conclusion: The results appear to be strongly affected by the small number of women with GM by P. vivax at childbirth. Additional studies are needed with larger groups in this and other regions of the country

Malaria: efficacy of amodiaquine-sulfadoxine-pyrimethamine, nutritional status and alellic variaton of CYP2C8 gen

Problema: La respuesta terapéutica antimalárica depende de múltiples determinantes asociados con el plasmodio (especie, mutaciones, cantidad, etc.) y al hospedero (nutrición, genes, metabolismo, etc.), pero los últimos son poco conocidos. Objetivos: Evaluar en pacientes con malaria falciparum no complicada, tratados con amodiaquina-sulfadoxina-pirimetamina (AQ-SP), algunas relaciones entre la respuesta terapéutica (RTA), el estado nutricional y las variaciones alélicas del gen CYP2C8. Metodología: Estudio clínico controlado, con asignación aleatoria, balanceado, no ciego. La RTA se evaluó según la Organización Mundial de la Salud. Se hizo análisis antropométrico, se midieron las concentraciones plasmáticas de retinol, ferritina y selenio; se analizaron las variantes 2C8*1 (silvestre), 2C8*2 (Il29F) y 2C8*3 (R139K y K399R) del gen CYP2C8. Resultados: Se evaluaron 33 pacientes, todos con respuesta terapéutica adecuada con AQ-SP; 10% presentó deficiencia de retinol, 25% de selenio y 40% de ferritina. Sólo un paciente presentó la variante CYP2C8*2 en forma heterozigótica y el resto fueron homocigóticos para el alelo silvestre de este gen. Ninguno presentó la mutación R139K en CYP2C8*3. Del alelo K339R de CYP2C8*3 no se pudieron obtener fragmentos aptos de digerir, aún haciendo adaptaciones del método y no fue posible conocer la razón de este hecho. Estos datos concuerdan con los resultados de otro análisis similar en 23 pacientes, tratados solo con amodiaquina: 22% presentaron alguna variante (5 con CYP2C8*2 y 2 con CYP2C8*3). En el gen CYP2C8*3 se identificó sólo la mutación R139K, presente en 2 individuos. Conclusión: Sólo uno de los 33 pacientes (3%) presentó la variante CYP2C8*2, en forma heterozigótica; el resto fueron homocigóticos para el alelo silvestre de esta variante. Ninguno presentó la mutación R139K de la variante CYP2C8*3. Es el primer informe para Latinoamérica. Problem: Therapeutic response to antimalarials depends on multiple determinants associated with the parasite (species, mutations, parasitaemia, etc.) and the host (nutrition, genes, metabolism, etc.), but little is known about the host factors. Objectives: To evaluate in non-complicated falciparum malaria patients undergoing treatment with amodiaquinesulfadoxine- pyrimethamine (AQ-SP), some relationships between treatment response, nutritional status and characteristics of the gen CYP2C8. Methodology: A randomly assigned, balanced, non blind, controlled clinical design. Treatment response was assessed according to WHO 1998 criteria. Analysis included anthropometry, plasma levels of retinol, ferritin and selenium, and assessment of 2C8*1 (wild), 2C8*2 (Il29F) and 2C8*3 variants of CYP2C8 (R139K y K399R). Results: 33 patients were studied, all of them evidenced adequate treatment response, 10% had retinol deficiency, 25% selenium deficiency and 40% low ferritine levels. One patient exhibited the variant Il29F of CYP2C8*2 in a heterozygous fashion, the remaining individuals were homozygous for the wild form of this gene. The mutant R139K of CYP2C8*3 was absent in all individuals. Amplification fragments obtained of K339R (CYP2C8*3 gen) were not suitable for digestion, regardless of the modifications performed. These results confirm previous findings made in 22% of 23 patients in whom some variation was observed (5 in CYP2C8*2 and 2 in CYP2C8*3). For CYP2C8*3 the mutant R139K, was observed in 2 individuals. Conclusion: only one of the 33 patients (3%) had CYP2C8*2 in a heterozygous fashion, the remaining were homozygous for the wild allele of this variant. None of the patients had the mutation R139K of the CYP2C8*3 variant. This is a novel report for Latin America

Genotype comparison of Plasmodium vivax and Plasmodium falciparum clones from pregnant and non-pregnant populations in North-west Colombia

ABSTARCT: Placental malaria is the predominant pathology secondary to malaria in pregnancy, causing substantial maternal and infant morbidity and mortality in tropical areas. While it is clear that placental parasites are phenotypically different from those in the peripheral circulation, it is not known whether unique genotypes are associated specifically with placental infection or perhaps more generally with pregnancy. In this study, genetic analysis was performed on Plasmodium vivax and Plasmodium falciparum parasites isolated from peripheral and placental blood in pregnant women living in North-west Colombia, and compared with parasites causing acute malaria in non-pregnant populations. Methods: A total of 57 pregnant women at delivery with malaria infection confirmed by real-time PCR in peripheral or placental blood were included, as well as 50 pregnant women in antenatal care and 80 men or non-pregnant women with acute malaria confirmed by a positive thick smear for P. vivax or P. falciparum. Five molecular markers per species were genotyped by nested PCR and capillary electrophoresis. Genetic diversity and the fixation index FST per species and study group were calculated and compared. Results: Almost all infections at delivery were asymptomatic with significantly lower levels of infection compared with the groups with acute malaria. Expected heterozygosity for P. vivax molecular markers ranged from 0.765 to 0.928 and for P. falciparum markers ranged from 0.331 to 0.604. For P. vivax infections, the genetic diversity was similar amongst the four study groups and the fixation index from each pairwise comparison failed to show significant genetic differentiation. For P. falciparum, no genetic differentiation was observed between placental and peripheral parasites from the same woman at delivery, but the parasites isolated at delivery showed significant genetic differentiation compared with parasites isolated from subjects with acute malaria. Conclusions: In North-west Colombia, P. vivax parasites have high genetic diversity that is equivalent in pregnant and non-pregnant populations as well as in symptomatic and asymptomatic infections. For P. falciparum, the overall genetic diversity is lower, with specific genotypes associated with asymptomatic infections at delivery

Functional antibodies against VAR2CSA in nonpregnant populations from Colombia exposed to Plasmodium falciparum and Plasmodium vivax

RESUMEN: En el embarazo, se observa inmunidad dependiente de la paridad en respuesta a la infección placentaria con Plasmodium falciparum. Los anticuerpos reconocen el antígeno de superficie, VAR2CSA, expresado en glóbulos rojos infectados e inhiben la citoadherencia al tejido placentario. En la mayoría de los entornos de endemicidad del paludismo, los anticuerpos contra VAR2CSA se observan predominantemente en las mujeres multigravidias y con poca frecuencia en hombres, niños y mujeres nulligráficas. Sin embargo, en Colombia, se detectaron anticuerpos contra múltiples constructos de VAR2CSA entre hombres y niños con infección aguda por P. falciparum y Plasmodium vivax. La mayoría de los hombres y niños (> 60%) tenían altos niveles de IgG contra tres dominios recombinantes de VAR2CSA: DBL5ε, DBL3X e ID1-ID2. Sorprendentemente, estos anticuerpos se observaron sólo en mujeres embarazadas, hombres y niños expuestos a P. falciparum oa P. vivax. Además, los anticuerpos anti-VAR2CSA son de alta avidez e inhiben eficazmente la adherencia de glóbulos rojos infectados al condroitín sulfato A in vitro, lo que sugiere que son específicos y funcionales. Estos resultados inesperados sugieren que puede haber diferencias genotípicas o fenotípicas en los parásitos de esta región o en la respuesta del huésped a la infección por P. falciparum o P. vivax fuera del embarazo. Estos hallazgos pueden tener relevancia clínica significativa para la fisiopatología y el resultado de las infecciones de malaria en esta región.ABSTRACT: In pregnancy, parity-dependent immunity is observed in response to placental infection with Plasmodium falciparum. Antibodies recognize the surface antigen, VAR2CSA, expressed on infected red blood cells and inhibit cytoadherence to the placental tissue. In most settings of malaria endemicity, antibodies against VAR2CSA are predominantly observed in multigravid women and infrequently in men, children, and nulligravid women. However, in Colombia, we detected antibodies against multiple constructs of VAR2CSA among men and children with acute P. falciparum and Plasmodium vivax infection. The majority of men and children (>60%) had high levels of IgGs against three recombinant domains of VAR2CSA: DBL5ε, DBL3X, and ID1-ID2. Surprisingly, these antibodies were observed only in pregnant women, men, and children exposed either to P. falciparum or to P. vivax. Moreover, the anti-VAR2CSA antibodies are of high avidity and efficiently inhibit adherence of infected red blood cells to chondroitin sulfate A in vitro, suggesting that they are specific and functional. These unexpected results suggest that there may be genotypic or phenotypic differences in the parasites of this region or in the host response to either P. falciparum or P. vivax infection outside pregnancy. These findings may hold significant clinical relevance to the pathophysiology and outcome of malaria infections in this region