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Item Antigenic diversity of Plasmodium falciparum and antibody-mediated parasite neutralization(Blackwell Scientific Publications, 1972) A Bolad, K BerzinsAbstract The malaria parasite Plasmodium falciparum, causing the most severe form of the disease in humans, is characterized by a broad antigenic diversity between different strains and isolates of the parasite. The antigenic diversity reflects on the one hand polymorphisms in allelic gene products and, on the other hand, antigenic variation as a result of expression of alternative genes in multigene families. Using selected polymorphic regions in two merozoite surface antigens, a method for genotyping P. falciparum parasites has been ...Item محمد صلى الله عليه وسلم في أسفار المجوس الزرادشتين(المؤلف, 1994) الشفيع الماحي أحمدItem ابعاد الحب النفسية من خلال التجربة الذاتية لابن حزم(المؤلف, 1998) الشفيع الماحي أحمدItem مشكلة خلق القرآن بين المعتزلة والأشاعرة(المؤلف, 1998) الشفيع الماحي أحمدItem Pf332 Repeat Sequences Inhibit Plasmodium Falciparum Growth In Vitro On Their Own And In Cooperation With Human Monocytes(1999-09-01) A Bolad, K BerzinsRepeat sequences from the Plasmodium falciparum blood stage antigen Pf332 frequently comprise the pentapeptide VTEEI, an epitope recognized by certain parasite neutralizing antibodies. This motif was assembled in octavalent multiple antigen peptides as trimers (VTEEI)3 (MAP1). We optimized in vitro conditions for studying the inhibition of P. falciparum growth with rabbit antibodies raised against MAP1. When total IgG was used, the parasite growth inhibitory effect was unexpectedly low and agglutination of the erythrocytes in the culture was observed in the microscope, indicating that the low inhibition obtained was due to presence of haemagglutinins. Haemagglutinins bind both infected and non infected red blood cells. When parasitised erythrocytes rupture, released merozoites infect non infected red blood cells. When haemagglutinins were removed by absorbtion the inhibitory capacity of IgG was considerably increased. Affinity purified Pf332 specific antibodies induced higher inhibition at lower levels than did the rabbit total IgG. We also found that MAP1-specific antibodies increased the capacity of monocytes to inhibit growth of parasites. Surface exposure of Pf332 makes it accessible to opsonic??ic antibodies involved in phagocytosis of parasite infected erythrocytes and can mediate cellular killing of parasite. Thus, Pf332 specific antibodies proved able to inhibit parasite growth on their own as well as in cooperation with normal human monocytes.Item البعد الايماني في فكر سعيد النورسي(المؤلف, 1999-12) الشفيع الماحي أحمدItem تناغم الزخارف الاسلامية مع الافريقية علي جداريات البوابة النوبية(المؤلف, 2000) مصطفي عبده محمد خيرItem الايقاع الكوني السباعي : تزاوج الاحوال الثلاثية من المرحلة الرابعة المتألقة من خلال الايقاع السباعي(المؤلف, 2000-02) مصطفي عبدهItem المرحلة الرابعة المتألقة للايقاع السباعي(المؤلف, 2000-09) مصطفي عبدهItem مدخل الي العقيدة الاسلامية(المؤلف, 2001) الشفيع الماحي أحمدItem منهج النورسي في شرح أسماء الله الحسنى(المؤلف, 2001-09) الشفيع الماحي أحمدItem عجائب علم الكلام الثلاث :طفرة النظام وكسب الأشعري وأحوال أبي هاشم(المؤلف, 2003) الشفيع الماحي أحمدItem البعد التبشيري في نبوة عيسي عليه السلام(المؤلف, 2003) الشفيع الماحي أحمدItem تمهيد لدراسة الديانة الفرعونية القديمة(المؤلف, 2003) الشفيع الماحي أحمدItem العقل الابداعي بوادر كنظرية جديدة في علم الجمال(المؤلف, 2003-03) مصطفي عبدهItem Antibody-mediated in vitro growth inhibition of field isolates of Plasmodium falciparum from asymptomatic children in Burkina Faso(The American Society of Tropical Medicine and Hygiene, 2003-06-01) Ahmed BoladAntibody-mediated inhibition of Plasmodium falciparum parasites in vitro reflects the potential parasite-neutralizing activity of the antibodies in vivo. In this study, immunoglobulins and P. falciparum isolates were collected from children with asymptomatic malaria in Burkina Faso. We demonstrate a significantly lower in vitro growth inhibitory activity against the P. falciparum field isolates by autologous host immunoglobulin compared with that of immunoglobulin from other individuals. To gain further insight to possible ...Item The Impact of the Use of Impregnated Curtains on Antibody Responses Againstplasmodium falciparumand on Complexity of Infecting Parasite Populations(A Bolad, 2003-08-01) A Bolad;Read 'The Impact of the Use of Impregnated Curtains on Antibody Responses AgainstPlasmodium falciparumand on Complexity of Infecting Parasite Populations' on Ovid Insights.Item Item Antibody responses in Plasmodium falciparum malaria and their relation to protection against the disease(Wenner-Grens institut för experimentell biologi, 2004) Ahmed Kamal BoladProtective immunity against Plasmodium falciparum may be obtained after repeated exposure to infection. Several studies indicate that immunity against the blood stages of the P. Falciparum infection is mainly antibody mediated. Protective antibodies may act either on their own, mediate antibody-dependent phagocytosis and/or cell-mediated neutralization of parasites. This thesis describes several aspects of humoral immune responses to P. falciparum infection in individuals of different age groups, different genetic background and with different degrees of malaria exposure. Several target antigens for antibody-mediated inhibition of parasite growth or invasion have been identified. One such antigen is Pf332, which appears on the surface of parasitized erythrocytes at late trophozoite and schizont stage. This surface exposure makes the antigen a possible target for opsonizing antibodies. We optimized an in vitro assay for studying cellmediated parasite neutralization in the presence of Pf332-reactive antibodies. Our data demonstrate that, Pf332 specific antibodies are able to inhibit parasite growth on their own and in cooperation with human monocytes. The P. falciparum parasites have evolved several mechanisms to evade the host neutralizing immune responses. In this thesis, we show that freshly isolated P. falciparum parasites from children living in a malaria endemic area of Burkina Faso were less sensitive for growth inhibition in vitro by autologous immunoglobulins (Ig) compared with heterologous ones. Analyses of two consecutive isolates taken 14 days apart, with regard to genotypes and sensitivity to growth inhibition in vitro, did not give any clear-cut indications on possible mechanisms leading to a reduced inhibitory activity in autologous parasite/antibody combinations. The frequent presence of persisting parasite clones in asymptomatic children indicates that the parasite possesses as yet undefined mechanisms to evade neutralizing immune responses. Transmission reducing measures such insecticide treated nets (ITNs) have been shown to be effective in reducing morbidity and mortality from malaria. However, concerns have been raised that ITNs usage could affect the acquisition of malaria immunity. We studied the effect of the use of insecticide treated curtains (ITC) on anti-malarial immune responses of children living in villages with ITC since birth. The use of ITC did neither affect the levels of parasite neutralizing immune responses nor the multiplicity of infection. These results indicate that the use of ITC does not interfere with the acquisition of anti-malarial immunity in children living in a malaria hyperendemic area. There is substantial evidence that the African Fulani tribe is markedly less susceptible to malaria infection compared to other sympatrically living ethnic tribes. We investigated the isotypic humoral responses against P. falciparum asexual blood stages in different ethnic groups living in sympatry in two countries exhibiting different malaria transmission intensities, Burkina Faso and Mali. We observed higher levels of the total malaria-specific-IgG and its cytophilic subclasses in individuals of the Fulani tribe as compared to non-Fulani individuals. Fulani individuals also showed higher levels of antibodies to measles antigen, indicating that the intertribal differences are not specific for malaria and might reflect a generally activated immune system in the Fulani.Item Antiplasmodial activity of seven plants used in African folk medicine(Medknow Publications on behalf of Indian Pharmacological Society, 2004) Ahmed Bolad, G Bidla; VPK Titanji, B Joko; G El-Ghazali, K BerzinsResults are expressed as mean+ SD. The differences between experimental groups were compared by one-way ANOVA (control Vs treatment) followed by Student-Neuman-Keuls test and were considered statistically significant at P< 0.05. The number of acetic acid induced writhings were significantly reduced by treatment with AO-1 in both the doses. The effect was found to be more than that of the standard, diclofenac (20 mg/kg) at a dose of 100 mg/kg (Table 1). AO-1 pretreatment significantly reduced the paw edema in rats. The effect ...