Duffy blood group system and the malaria adaptation process in humans

Malaria is an acute infectious disease caused by the protozoa of the genus Plasmodium. The antigens of the Duffy Blood Group System, in addition to incompatibilities in transfusions and hemolytic disease of the newborn, are of great interest in medicine due to their association with the invasion of red blood cells by the parasite Plasmodium vivax. For invasions to occur an interaction between the parasites and antigens of the Duffy Blood Group System is necessary. In Caucasians six antigens are produced by the Duffy locus (Fya, Fyb, F3, F4, F5 and F6). It has been observed that Fy(a-b-) individuals are resistant to Plasmodium knowlesi and P. vivax infection, because the invasion requires at least one of these antigens. The P. vivax Duffy Binding Protein (PvDBP) is functionally important in the invasion process of these parasites in Duffy / DARC positive humans. The proteins or fractions may be considered, therefore, an important and potential inoculum to be used in immunization against malaria.

Duffy Blood Group System and the malaria adaptation process in humans.

Malaria is an acute infectious disease caused by the protozoa of the genus Plasmodium. The antigens of the Duffy Blood Group System, in addition to incompatibilities in transfusions and hemolytic disease of the newborn, are of great interest in medicine due to their association with the invasion of red blood cells by the parasite Plasmodium vivax. For invasions to occur an interaction between the parasites and antigens of the Duffy Blood Group System is necessary. In Caucasians six antigens are produced by the Duffy locus (Fya, Fyb, F3, F4, F5 and F6). It has been observed that Fy(a-b-) individuals are resistant to Plasmodium knowlesi and P. vivax infection, because the invasion requires at least one of these antigens. The P. vivax Duffy Binding Protein (PvDBP) is functionally important in the invasion process of these parasites in Duffy / DARC positive humans. The proteins or fractions may be considered, therefore, an important and potential inoculum to be used in immunization against malaria.

Organização estrutural do taquizoíto de toxoplasma gondii: [revisão] / Structural organization of the tachyzoite of toxoplasma gondii: [review]

Objetivos: fazer uma revisão dos aspectos básicos da ultraestrutura do taquizoíto de Toxoplasma gondii, agente etiológico da toxoplasmose. Fonte de dados: os dados apresentados tomam como referência resultados recentes obtidos pelos principais grupos de pesquisadores no mundo, que se dedicam ao estudo do Toxoplasma gondii, incluindo-se dados do próprio grupo de autores. Síntese dos dados: os taquizoítos de Toxoplasma gondii são responsáveis pela fase aguda da infecção, penetrando ativamente, através do complexo apical, em células dos hospedeiros onde se multiplicam. São abordadas características ultraestruturais e moleculares particulares da película, do citoesqueleto, de organelas secretórias (róptrias, micronemas e grânulos densos) e não secretórias (apicoplasto) exclusivas do filo Apicomplexa, além das peculiaridades do núcleo, mitocôndria, acidocalcisomas, retículo endoplasmático e complexo de Golgi desses parasitos intracelulares. Conclusões: estas características confirmam que o sucesso nas etapas de adesão, invasão e multiplicação do parasito possui clara correlação com suas características morfofuncionais.

Aims: To review basic aspects on the ultrastructure of the tachyzoite of Toxoplasma gondii, the causative agent of toxoplasmosis. Source of data: The data presented are based on recent publications by the most distinguished research groups in the area dedicated to the study of Toxoplasma gondii, including studies from the present authors. Summary of findings: The tachyzoites are responsible for the acute phase of the infection by actively penetrating, through the parasites? apical complex, the host cells where they multiply. Both ultrastructural and molecular particularities of the pellicle, the cytoskeleton, secretory (rhoptries, micronemas and dense granules) and non secretory (apicoplast) organelles, specific to Apicomplexa phylum, besides peculiar features of the nucleus, mitochondrion, acidocalcisomes, endoplasmic reticulum and Golgi complex of these intracellular parasites. Conclusions: These characteristics confirm that the success in the process of adhesion, invasion and multiplication of this parasite is clearly correlated to its morphology.

Detection of Giardia lamblia antigen in stool specimens using enzyme-linked immunosorbent assay

The aim of this study in Iraq was to determine the sensitivity and specificity of a commercial ELISA test for detection of Giardia lamblia antigen in stool. Of 84 stool samples from children in Duhok governorate, 42 were positive and 42 negative for G. lamblia or other parasites by direct and indirect microscopic examination. The sensitivity of the ELISA test for detection of G. lamblia versus microscopy was 76.4% and the specificity was 100%. We recommend using ELISA in epidemiological surveys in Iraq and to confirm the diagnosis in patients with typical clinical symptoms of giardiasis but negative results by direct microscopy

Visceral leishmaniasis in the Syrian Arab Republic: early detection using rK39

Leishmaniasis causes significant morbidity and mortality in areas where it is endemic. A seroprevalence survey was conducted in 2 endemic villages in Daraa, Syrian Arab Republic, where 80 out of 345 children [23.2%] tested positive for visceral leishmaniasis [VL] using rK39 dipstick test. Only 10 cases were symptomatic [12.5%], and 27.5% were positive by ELISA test. All the sera [N = 138] obtained from the control village were negative. Of the rK39 initially positive cases, 52 had seroconverted to negative 9 months later, 55 remained ELISA negative, and none developed the full-blown disease. Being faster and less expensive than other diagnostic tests, rK39 is a rapid, sensitive and specific diagnostic tool for symptomatic cases of VL in remote areas with poor accessibility to health services

Field evaluation of latex agglutination test for detecting urinary antigens in visceral leishmaniasis in Sudan

A latex agglutination test to detect urinary antigens for visceral leishmaniasis [VL] was studied. In 204 patients with suspected VL, KAtex had a sensitivity of 95.2% with good agreement with microscopy smears but poor agreement with 4 different serology tests. It was also positive in 2 confirmed VL cases co-infected with HIV. In all KAtex-positive confirmed cases actively followed up after treatment, the test became negative 1 month after completion of treatment. While KAtex had a specificity of 100% in healthy endemic and non-endemic controls, the direct agglutination test [DAT] was positive in 14% of the KAtex-negative healthy endemic controls. KAtex is a simple addition to the diagnostics of VL particularly at field level and as a complementary test for the diagnosis of VL in smear-negative cases with positive DAT results

Estimation of malaria transmission in high-risk provinces of Morocco

The malaria transmission level of Plasmodium vivax was monitored in four high-risk provinces in Morocco. Intensive mosquito collection by light traps and manual catches resulted in the capture of four species: Anopheles labranchiae, An. sergenti, An. cinereus, and An. claviger. All An. sergenti and An. labranchiae females collected were tested for the presence of two phenotypes of P. vivax [PVK210 and PVK247] antigen by enzyme-linked immunosorbent assay [ELISA]. No P. vivax antigen was detected in 1347 mosquitoes analysed. A parallel parasitological investigation was conducted. Of 2665 slides examined from a population of 4343 people for detection of P. vivax, no slide was positive. The results confirm the break in malaria transmission in residual foci. The use of ELISA is recommended in future epidemiological studies of human malaria

Post kala azar dermal leishmaniasis in Sudan

Post kala azar dermal leishmaniasis [PKDL] is a condition that develops after treatment of kala azar. We report on 42 patients with suspected PKDL, 40% of whom were children. Diagnosis was made though investigation of family history of kala azar, clinical examination and the use of laboratory investigations, such as skin smear, skin biopsy, bone marrow aspiration and the leishmanin skin test. Regarding the lesions, 24 patients [57%] had papular lesions, 10 [24%] had hypopigmented maculopapular lesions and 8 [19%] had nodular lesions. The lesions of PKDL may be confused with other dermatological diseases and therefore it is important that clinicians and pathologists collaborate in diagnosing such cases

Expression and purification of soluble fusion protein of Toxoplasma gondii GRA6 in E.coli / 中华传染病杂志

Objective To high express and purify toxoplasma gondii antigen GRA6 in E.coli which can be used to develop the genetic engineering diagnostic reagents.Methods The recombinant plasmid of pGEX-GRA6 was transformed to a bacterium BL21-Codon Plus(DE3)-RP and the recom- binant product was expressed under the inducement of isopropyl-beta-D-thiogalactosidase(IPTG). Cells were lysed by multiple rounds of sonication.The expression product was analyzed by using SDS- PAGE.Furthermore,it was purified by sedimentation of ammonium sulphate,desalting using Sephe- dax GS0 and affinity chromatography on glutathione-sepharose system.The immunogenicity of recom binant antigen purified was tested with Western blot.Results GRA6 was highly expressed in E.coli as fusion protein consisting of glutathione S-transferase and GRA6(GST-GRA6).The solubility anal- ysis of expression product indicated that this recombinant protein could be expressed in both superna- tant and inclusion bodies.The soluble protein of GRA6 in supernatant yield the final preparation at greater than 90% after purification.The recombinant protein purified could be recognized by human toxoplasmosis-infective sera with Western blotting analysis.Conclusions The soluble protein of GRA6 was highly expressed in E.coli and the recombinant antigen could be recognized by human tox- oplasmosis-infective serum after purification.The recombinant antigen can be used for devoloping kit to diagnose the acute and chronic infection of toxoplasma gondii.

Toxoplasma gondii: caracterización de un anticuerpo monoclonal anti-P30

Se caracterizó un anticuerpo monoclonal específico a Toxoplasma gondii. El hibridoma produjo inmunoglobulinas IgG. El análisis por Western Blot demostró que el anticuerpo monoclonal fue específico para el antígeno de masa molecular aparente de 30 kd, presente en la superficie del parásito. El anticuerpo monoclonal se purificó a partir de fluido ascítico de ratón y se acopló a Sefarosa 4B. Este inmunoabsorbente fue utilizado con el fin de purificar el antígeno parasitario específico. El anticuerpo monoclonal estudiado puede ser de utilidad para las técnicas que contribuyan con el diagnóstico de la toxoplasmosis.

A specific monoclonal antibody was characterized to Toxoplasma gondii. The hybridoma produced IgG immunoglobulins. The Western Blot analysis showed that the monoclonal antibody was specific for the antigen of an apparent mollecular mass of 30 kd, which was present on the antigen surface. The monoclonal antibody was purified starting from mouse´s ascitic fluid and it was matched with Sepharose 4B. This immunoabsorbent was used to purify the specific parasitary antigen. The monoclonal antibody studied may be useful for those tecniques contributing to the toxoplasmosis diagnosis.