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- Iriemenam, Nnaemeka C, et al.
(författare)
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Cytokine profiles and antibody responses to Plasmodium falciparum malaria infection in individuals living in Ibadan, southwest Nigeria.
- 2009
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Ingår i: African Health Sciences. - 1680-6905 .- 1729-0503. ; 9:2, s. 66-74
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: The ability of the host immune system to efficiently clear Plasmodium falciparum parasites during a malaria infection depends on the type of immune response mounted by the host. STUDY DESIGN: In a cross-sectional study, we investigated the cellular-and antibody responses in individuals with P. falciparum infection, in an attempt to identify immunological signs indicative of the development of natural immunity against malaria in Ibadan, Nigeria. Levels of IL-10, IL-12(p70), IFN-gamma, and IgM, IgG and IgG1-4 subclasses in the serum of 36 symptomatic children with microscopically confirmed malaria parasitaemia and 54 asymptomatic controls were analysed by ELISA. RESULTS: IFN-gamma and IL-10 were significantly higher in the symptomatic children (p=0.009, p=0.025 respectively) than in the asymptomatic controls but no differences were seen for IL-12(p70). Estimated higher ratios of IFN-gamma/IL-10 and IFN-gamma/IL-12 were also observed in the symptomatic children while the asymptomatic controls had higher IL-12/IL-10 ratio. The mean concentration levels of anti-P. falciparum IgG1, IgG2, IgG3 antibodies were statistically significantly higher in the individuals >5 years of age than <5 years while anti-P. falciparum IgG3 antibodies were notably low in <5 years category. Children <5 years had higher IgM antibodies than IgG and the expression of IgG subclasses increased with age. CONCLUSION: Taken together, malaria infection is on a delicate balance of pro- and anti-inflammatory cytokines. The higher levels of IFN-gamma seen in the symptomatic children (<6 months) may be instrumental in immune-protection against malaria by limiting parasite replication. The observed variations in immunoglobulin subclass levels were age-dependent and exposure-related.
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- Ali, Magdi M. M., et al.
(författare)
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Fc gamma RIIa (CD32) polymorphism and onchocercal skin disease : implications for the development of severe reactive onchodermatitis (ROD)
- 2007
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Ingår i: American Journal of Tropical Medicine and Hygiene. - Lawrence, Kans. : American society of tropical medicine and hygiene. - 0002-9637 .- 1476-1645. ; 77:6, s. 1074-8
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Tidskriftsartikel (refereegranskat)abstract
- The pathologic manifestations of Onchocerca volvulus infection depend on the interplay between the host and the parasite. A genetic single nucleotide polymorphism in the Fc gamma RIIa gene, resulting in arginine (R) or histidine (H) at position 131, affects the binding to the different IgG subclasses and may influence the clinical variations seen in onchocerciasis. This study investigated the relationship between this polymorphism and disease outcome. Fc gamma RIIa genotyping was performed on clinically characterized onchocerciasis patients (N = 100) and healthy controls (N = 74). Fc gamma RIIa genotype R/R131 frequencies were significantly higher among patients with severe dermatopathology (P < 0.001). Increased risk of developing this form was mostly associated with one tribe (Masalit) (OR = 3.2, 95% CI 1-9.9, P = 0.042). The H131 allele was found to be significantly associated with a reduced risk of having the severe form of the disease (adjusted OR = 0.26, 95% CI = 0.13-0.46, P < 0.001). Our findings suggest that the polymorphism influences the clinical outcome of onchocerciasis.
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- Bolad, A K, et al.
(författare)
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The use of impregnated curtains does not affect antibody responses against Plasmodium falciparum and complexity of infecting parasite populations in children from Burkina Faso
- 2004
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Ingår i: Acta Tropica. - : Elsevier B.V.. - 0001-706X .- 1873-6254. ; 90:3, s. 237-247
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Tidskriftsartikel (refereegranskat)abstract
- In Burkina Faso, where malaria is hyper-endemic and transmission intensity is very high, the majority of malaria-related morbidity and mortality occurs in children less than 5 years of age. A control measure such as the use of insecticide-treated curtains (ITC) significantly reduces transmission of malaria infection. Concerns remain whether reduced transmission intensity may lead to a delay in the development of immunity in younger children and even to a partial loss of already acquired immunity. In this study, the levels of P. falciparum-specific IgG subclasses, the number of infecting parasite clones determined by PCR-based genotyping of the msp2 gene and the parasite density were analysed in 154 asymptomatic children (3–6 years) living in 16 villages (8 with and 8 without ITC) in the vicinity of Ouagadougou, the capital of Burkina Faso. In addition, the parasite inhibitory effects of Ig fractions, prepared from selected children, in co-operation with normal human monocytes were studied. Blood samples from asymptomatic ITC-users showed a significant decrease in P. falciparum prevalence as well as in parasite density. However, no significant difference was observed in P. falciparum-specific antibodies or in parasite multiplicity of infection between the two groups. Furthermore, Ig fractions from children of both groups showed similar levels of inhibitory activity against autologous parasite growth both on their own and in co-operation with monocytes.
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- Iriemenam, Nnaemeka C., et al.
(författare)
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Antibody responses to a panel of Plasmodium falciparum malaria blood-stage antigens in relation to clinical disease outcome in Sudan
- 2009
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Ingår i: Vaccine. - Amsterdam : Elsevier. - 0264-410X .- 1873-2518. ; 27:1, s. 62-71
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Tidskriftsartikel (refereegranskat)abstract
- Despite many intervention programmes aimed at curtailing the scourge, malaria remains a formidable problem of human health. Immunity to asexual blood-stage of Plasmodium falciparum malaria is thought to be associated with protective antibodies of certain immunoglobulin classes and subclasses. We have analysed immunoglobulin G profiles to six leading blood-stage antigens in relation to clinical malaria outcome in a hospital-based study in Sudan. Our results revealed a linear association with anti-AMA-1-IgG1 antibodies in children <5 years and reduced risk of severe malaria, while the responses of the IgG3 antibodies against MSP-2, MSP-3, GLURP in individuals above 5 years were bi-modal. A dominance of IgG3 antibodies in >5 years was also observed. In the final combined model, the highest levels of IgG1 antibodies to AMA-1, GLURP-R0, and the highest levels of IgG3 antibodies to 3D7 MSP-2 were independently associated with protection from clinical malaria. The study provides further support for the potential importance of the studied merozoite vaccine candidate antigens as targets for parasite neutralizing antibody responses of the IgG1 and IgG3 subclasses.
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