Shahid Waseem; Kashif-Ur-Rehman -; Ramesh Kumar; Tariq Mahmood
Volume 13, Issue 1 , March 2016, , Pages 1-8
Abstract
Background: Falciparum malaria is a severe health burden worldwide. Antigen presenting cells are reported to be affected by erythrocytic stage of the parasite. Malarial hemozoin (HZ), a metabolite of malaria parasite, has adjuvant properties and may play a role in the induction of immune response against ...
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Background: Falciparum malaria is a severe health burden worldwide. Antigen presenting cells are reported to be affected by erythrocytic stage of the parasite. Malarial hemozoin (HZ), a metabolite of malaria parasite, has adjuvant properties and may play a role in the induction of immune response against the parasite. Objective: To determine the immunological impact of hemozoin on the capacity of innate immune cells maturation. Methods: Plasmodium falciparum (F32 strain) was cultured in O+ blood group up to 18% parasitemia. Natural hemozoin was extracted from infected red blood cells. Murine bone marrow derived macrophages and myeloid dendritic cells were stimulated with 4 ߤg/mL or 40 ߤg/mL of synthetic hemozoin (β-hematin) or natural hemozoin. We assessed the immunomodulatory role of synthetic or natural hemozoin in vitro by flowcytometric analysis. Results: The maturation markers MHCII, CD80 and CD86 were significantly upregulated (p<0.05) on the surface of murine bone marrow derived macrophages or myeloid dendritic cells. Data confirmed the potential of macrophages or myeloid dendritic cells, through hemozoin activation, to establish an innate immune response against malaria parasites. Conclusion: Both synthetic and natural hemozoin are potent inducers of cellular immunity against malaria infection. However, natural hemozoin is a stronger inducer as compared to synthetic hemozoin.
Babacar Mbengue; Birahim Niang; Bacary Diatta; Adama Tali; Olivier Garraud; Ronald Perraut; Alioune Dieye
Volume 7, Issue 3 , September 2010, , Pages 150-161
Abstract
Background: Cerebral malaria (CM) is one of the major causes of death in African populations infected with Plasmodium falciparum. Only 1% of infected subjects develop CM. The reasons for these differences are not fully understood, but it is likely that the host humoral response against blood-stage antigens ...
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Background: Cerebral malaria (CM) is one of the major causes of death in African populations infected with Plasmodium falciparum. Only 1% of infected subjects develop CM. The reasons for these differences are not fully understood, but it is likely that the host humoral response against blood-stage antigens plays a role in protection from malaria, although the precise targets and mechanisms mediating immunity remain unclear. Objective: The purpose of this study was to distinguish between defined P. falciparum- specific Ab response patterns in patients presenting with mild malaria (MM) vs. CM. Methods: We used a panel of P. falciparum conserved antigens including crude blood-stage extracts schizont, merozoite and parasitised erythrocyte membranes and MSP-1p19, PfEB200, R23 and GST-5 recombinant antigens in a retrospective casecontrol study of symptomatic adults, one group presenting confirmed CM without fatal outcome and another group with MM. We further matched P. falciparum-specific Ab responses with those from individuals living in an endemic setting known to have protective immunity and considered them as “immune control” subjects (IC). Total IgG, IgM and IgG subclass Ab responses were determined using ELISA method. Results: Substantial Ab responses were found in symptomatic patients, significantly lower than the “immune control” subjects, and with a limited quantitative difference between MM versus CM. Interestingly, asynchronous IgM response was evidenced in CM contrary to MM. Conclusion: Our results suggest that the contribution of an efficient IgG response against parasite multiplication is of importance in the evolution towards CM manifestation without fatal outcome and deserves further analysis for vaccine candidates.