Extracellular release of acid phosphatase from blood stream forms of Trypanosoma brucei brucei .

Acid phosphatase (ACP) activity was demonstrated in blood stream form of Trypanosoma brucei brucei harvested from infected Wister rats by Ion Exchange DEAE Cellulose 52 chromatography. Whole parasite extract (WPE) and Excretory Secretory Extract (ESE) were prepared and analyzed for acid phosphatase activity. A higher ACP activity (85.5 \u3bcmol/min) was recorded in WPE compared to ESE (36.8 \u3bcmol/min). ACP activity in ESE is suggestive of the presence of a cell rich enzyme. Phase separation of the extracts using the detergent Triton X-114 (TX-114), resulted in protein partitioning into aqueous and detergent phases. ACP activity was higher in the detergent phases (56.2 \u3bcmol/min and 28.8 \u3bcmol/min) of WPE and ESE respectively. ACP activity recorded in the aqueous phases of WPE and EPE was 27.8 and 7.6 \u3bcmol/min respectively. On a Size Exclusion chromatography column using Sephacryl-300, ESE emerged as five distinct protein peaks. ACP activity of the eluted fractions showed two peaks of relative molecular weights 195 and 325 KD. This study shows that T. brucei releases acid phosphatase extracellularly via a yet to be determined mechanism. Acid phosphatase activity in ESE is indicative of a soluble enzyme within the cell matrix which may also play an important role in the pathology of African Trypanosomiasis

Extracellular release of acid phosphatase from blood stream forms of Trypanosoma brucei brucei .

Acid phosphatase (ACP) activity was demonstrated in blood stream form of Trypanosoma brucei brucei harvested from infected Wister rats by Ion Exchange DEAE Cellulose 52 chromatography. Whole parasite extract (WPE) and Excretory Secretory Extract (ESE) were prepared and analyzed for acid phosphatase activity. A higher ACP activity (85.5 μmol/min) was recorded in WPE compared to ESE (36.8 μmol/min). ACP activity in ESE is suggestive of the presence of a cell rich enzyme. Phase separation of the extracts using the detergent Triton X-114 (TX-114), resulted in protein partitioning into aqueous and detergent phases. ACP activity was higher in the detergent phases (56.2 μmol/min and 28.8 μmol/min) of WPE and ESE respectively. ACP activity recorded in the aqueous phases of WPE and EPE was 27.8 and 7.6 μmol/min respectively. On a Size Exclusion chromatography column using Sephacryl-300, ESE emerged as five distinct protein peaks. ACP activity of the eluted fractions showed two peaks of relative molecular weights 195 and 325 KD. This study shows that T. brucei releases acid phosphatase extracellularly via a yet to be determined mechanism. Acid phosphatase activity in ESE is indicative of a soluble enzyme within the cell matrix which may also play an important role in the pathology of African Trypanosomiasis

Epidemiological factors that promote the development of severe malaria anaemia in children in Ibadan

Background: Effective control and management of severe malaria cases depends on a clear understanding of the local epidemiologicalfactors and specific clinical manifestations of the disease in the different endemic regions. Objectives: To determine the prevalence of severe malaria and epidemiological factors that affect the development of malaria anaemia. Methods: A cross-sectional survey was carried out among children below 5 years of age, at the Adeoyo State Maternity Hospital,Ibadan, Nigeria. Questionnaires and case histories were taken from patients clinically diagnosed of malaria.Thus, 372 volunteers wererecruited into the study from the 3131 paediatric cases that reported over the10-week period to the out-patient department (OPD) ofthe hospital. 229 (61.6%) of the recruited volunteers presented with fever (>37.5 oC) at consultation.These had malaria parasite andPCV tests done. Results: Clinical diagnosis was confirmed microscopically in 78% (290/372) for Plasmodium infection using thick film slides.Anaemia (PC

The Human Immune Response to Plasmodium falciparum Includes Both Antibodies That Inhibit Merozoite Surface Protein 1 Secondary Processing and Blocking Antibodies

Malaria merozoite surface protein 1 (MSP1) is cleaved in an essential step during erythrocyte invasion. The responses of children to natural malaria infection included antibodies that inhibit this cleavage and others that block the binding of these inhibitory antibodies. There was no correlation between the titer of the antibody to the 19-kDa fragment of MSP1 and its inhibitory activity. These findings have implications for the design of MSP1-based vaccines

Fine specificity of anti-MSP1₁₉antibodies and multiplicity of <it>Plasmodium falciparum </it>Merozoite Surface Protein 1 types in individuals in Nigeria with sub-microscopic infection

Abstract Background The absence of antibodies specific for the 19 kDa C-terminal domain of merozoite surface protein 1 (MSP119) has been associated with high-density malaria parasitaemia in African populations. The hypothesis that a high prevalence and/or level of anti-MSP119 antibodies that may inhibit erythrocyte invasion would be present in apparently healthy individuals who harbour a sub-microscopic malaria infection was tested in this study. Methods Plasma samples were collected from residents in a region in Nigeria hyperendemic for malaria, who had no detectable parasitaemia by microscopy. Using a competition-based enzyme-linked-immunosorbent assay with two invasion-inhibitory monoclonal antibodies (mAbs) 12.10 and 12.8, the levels and prevalence of specific antibodies were measured. The minimum multiplicity of infection was determined using PCR. The prevalence of anaemia was also measured. Results Plasma samples from 85% of individuals contained antibodies that bound to MSP119. The inhibition of mAb 12.10 binding was strongly correlated with the prevalence (Spearman correlation test, p 19 antibodies (Spearman correlation test, p 19 antibodies that competed with mAb 12.10. Using a logistic regression model, it was found that the presence of antibodies competitive with mAb 12.10 was affected negatively by anaemia (p = 0.0016) and positively by the carriage of multiple parasite genotypes (p = 0.04). Conclusions In the search for correlates of protection against malaria, which will be essential to evaluate clinical trials of malaria vaccines based on MSP1, this study examines some potential assays and the factors that need to taken into account during their evaluation, using samples from individuals naturally exposed to malaria infection.</p