Essential Domains of Anaplasma phagocytophilum Invasins Utilized to Infect Mammalian Host Cells

Anaplasma phagocytophilum causes granulocytic anaplasmosis, an emerging disease of humans and domestic animals. The obligate intracellular bacterium uses its invasins OmpA, Asp14, and AipA to infect myeloid and non-phagocytic cells. Identifying the domains of these proteins that mediate binding and entry, and determining the molecular basis of their interactions with host cell receptors would significantly advance understanding of A. phagocytophilum infection. Here, we identified the OmpA binding domain as residues 59 to 74. Polyclonal antibody generated against a peptide spanning OmpA residues 59 to 74 inhibited A. phagocytophilum infection of host cells and binding to its receptor, sialyl Lewis x (sLex-capped P-selectin glycoprotein ligand 1. Molecular docking analyses predicted that OmpA residues G61 and K64 interact with the two sLex sugars that are important for infection, α2,3-sialic acid and α1,3-fucose. Amino acid substitution analyses demonstrated that K64 was necessary, and G61 was contributory, for recombinant OmpA to bind to host cells and competitively inhibit A. phagocytophilum infection. Adherence of OmpA to RF/6A endothelial cells, which express little to no sLex but express the structurally similar glycan, 6-sulfo-sLex, required α2,3-sialic acid and α1,3-fucose and was antagonized by 6-sulfo-sLex antibody. Binding and uptake of OmpA-coated latex beads by myeloid cells was sensitive to sialidase, fucosidase, and sLex antibody. The Asp14 binding domain was also defined, as antibody specific for residues 113 to 124 inhibited infection. Because OmpA, Asp14, and AipA each contribute to the infection process, it was rationalized that the most effective blocking approach would target all three. An antibody cocktail targeting the OmpA, Asp14, and AipA binding domains neutralized A. phagocytophilumbinding and infection of host cells. This study dissects OmpA-receptor interactions and demonstrates the effectiveness of binding domain-specific antibodies for blocking A. phagocytophilum infection

The dominant Anopheles vectors of human malaria in Africa, Europe and the Middle East: occurrence data, distribution maps and bionomic précis

<p>Abstract</p> <p>Background</p> <p>This is the second in a series of three articles documenting the geographical distribution of 41 dominant vector species (DVS) of human malaria. The first paper addressed the DVS of the Americas and the third will consider those of the Asian Pacific Region. Here, the DVS of Africa, Europe and the Middle East are discussed. The continent of Africa experiences the bulk of the global malaria burden due in part to the presence of the <it>An. gambiae </it>complex. <it>Anopheles gambiae </it>is one of four DVS within the <it>An. gambiae </it>complex, the others being <it>An. arabiensis </it>and the coastal <it>An. merus </it>and <it>An. melas</it>. There are a further three, highly anthropophilic DVS in Africa, <it>An. funestus</it>, <it>An. moucheti </it>and <it>An. nili</it>. Conversely, across Europe and the Middle East, malaria transmission is low and frequently absent, despite the presence of six DVS. To help control malaria in Africa and the Middle East, or to identify the risk of its re-emergence in Europe, the contemporary distribution and bionomics of the relevant DVS are needed.</p> <p>Results</p> <p>A contemporary database of occurrence data, compiled from the formal literature and other relevant resources, resulted in the collation of information for seven DVS from 44 countries in Africa containing 4234 geo-referenced, independent sites. In Europe and the Middle East, six DVS were identified from 2784 geo-referenced sites across 49 countries. These occurrence data were combined with expert opinion ranges and a suite of environmental and climatic variables of relevance to anopheline ecology to produce predictive distribution maps using the Boosted Regression Tree (BRT) method.</p> <p>Conclusions</p> <p>The predicted geographic extent for the following DVS (or species/suspected species complex*) is provided for Africa: <it>Anopheles </it>(<it>Cellia</it>) <it>arabiensis</it>, <it>An. </it>(<it>Cel.</it>) <it>funestus*</it>, <it>An. </it>(<it>Cel.</it>) <it>gambiae</it>, <it>An. </it>(<it>Cel.</it>) <it>melas</it>, <it>An. </it>(<it>Cel.</it>) <it>merus</it>, <it>An. </it>(<it>Cel.</it>) <it>moucheti </it>and <it>An. </it>(<it>Cel.</it>) <it>nili*</it>, and in the European and Middle Eastern Region: <it>An. </it>(<it>Anopheles</it>) <it>atroparvus</it>, <it>An. </it>(<it>Ano.</it>) <it>labranchiae</it>, <it>An. </it>(<it>Ano.</it>) <it>messeae</it>, <it>An. </it>(<it>Ano.</it>) <it>sacharovi</it>, <it>An. </it>(<it>Cel.</it>) <it>sergentii </it>and <it>An. </it>(<it>Cel.</it>) <it>superpictus*</it>. These maps are presented alongside a bionomics summary for each species relevant to its control.</p

Effect Of Interval Training On Blood Pressure And Exercise Capacity In Hypertension: A Randomized Controlled Study

Mean arterial blood pressure (MAP) is a determinant of cardiovascular risk in patient with hypertension. The primary purpose of the present study was to investigate the effect of interval training program on MAP in black African subjects with hypertension. Two hundred and forty five male patients with mild to moderate (Systolic Blood Pressure [SBP] between 140-179 &amp; Diastolic Blood Pressure [DBP] between 90-109 mmHg) essential hypertension were age-matched and randomly assigned to interval(n=140) and control groups (n=105). The interval (work: rest ratio of 1:1) groups involved in an 8-weeks interval training programs of between 45-60&#160; minutes, at intensities of 60-79% of HR max, while the control group remained sedentary during this period. SBP, DBP, VO2max and MAP were assessed. Findings of the study revealed significant correlation between MAP and BP (SBP, r=.958; DBP, r=.342); correlation of MAP with SBP was much stronger (54% variance). Also, there was significant effect of exercise training program on MAP (p=0.000). Changes in VO2max also negatively correlated with changes in MAP (r= -.237) at p&lt;0.05. It was concluded that moderate intensity interval training programs is effective in the non-pharmacological management of hypertension and may prevent cardiovascular event through the down regulation of MAP in hypertension. Our findings support the recommendations of moderate intensity interval training program as an adjunct non-pharmacological management of essential hypertension. Key words: Hypertension; Interval exercise; Mean arterial blood pressure; Blood pressur

In Vitro Antimicrobial Evaluation of African Nutmeg (Monodora Myristica) Seeds

The organic (Hexane and ethanol) and aqueous extracts of African nutmeg (Monodora myristica) seeds were studied on isolates of Staphylococcus aureus, Escherichia coli, Bacillus cereus, Pseudomonas aeruginosa, Klebsiella pneumoniae, Proteus mirabilis, Salmonella typhi and Candida albicans using agar well diffusion technique at extract concentrations of 200, 100,&nbsp; and 50 mg/ml. The result showed that the various extracts displayed varying degrees of activities with the ethanolic extract demonstrating the highest activity, followed by hexane extract, against all the test isolates. Only S. aureus, E. coli, and B. cereus, were inhibited by the aqueous extracts. Susceptibility increased with concentrations and at 200 mg/ml, S. aureus, E. coli, P aeruginosa, B. cerus, P. mirabilis and C. albicans were generally more susceptible to the organic extracts than S. typhi, and K. pnuemoniae. The antimicrobial zones of inhibition of the organic extracts ranged between 8.0 and 16.0 mm as against 7.0 and 9.0 mm obtained from the aqueous extract at 200 mg/ml. The minimum inhibitory concentration values ranged from 12.5 - 100 mg/ml for the organic extracts. This study suggests that the extracts of African nutmeg posses antimicrobial properties against common pathogenic organisms. Keywords: African nutmeg, Monodora myristica, antimicrobial properties, clinical isolate

Seroprevalence of human T-cell lymphoma/leukemia virus type-1 (HTLV-1) antibodies among blood donors at Enugu, Nigeria

Augustine Ejike Okoye,1 Obike Godswill Ibegbulam,2 Robinson Chukwudi Onoh,3 Ngozi Immaculata Ugwu,1 Chukwudi Simon Anigbo,2 Charles Emeka Nonyelu2 1Department of Haematology and Immunology, Federal Teaching Hospital Abakaliki, Ebonyi State, Nigeria; 2Department of Haematology and Immunology, University of Nigeria Teaching Hospital (UNTH) Ituku-Ozalla, Enugu State, Nigeria; 3Department of Obstetrics and Gynaecology, Federal Teaching Hospital Abakaliki, Ebonyi State, Nigeria Background: Human T-cell lymphotrophic/leukemia virus (HTLV-1) is a retrovirus implicated in transfusion-transmitted infection. Objective: The objective of this study was to determine the seroprevalence of HTLV-1 antibodies among blood donors at the University of Nigeria Teaching Hospital, Enugu, Eastern Nigeria. Methods: A cross-sectional study was carried out on consented participants over 4 months. A total of 300 blood donors were recruited consecutively from the blood bank. The serum of the collected 5 mL of blood obtained from each participant was stored at -20&deg;C until required for analysis. The serum samples were then analyzed for antibodies to HTLV-1 using a one-step incubation double-antigen sandwich ELISA (enzyme-linked immunosorbent assay) kit. Participants&#39; demographic characteristics and degree of exposure to the risk factors associated with HTLV-1 infection were captured using a questionnaire. Statistical analysis of results was done using SPSS version 17. Results: Of the 300 blood donors, 288 (96%) were male, while 12 (4%) were female. The average age of the blood donors was 26.85&plusmn;8.52 years. The age group with the highest representation among the blood donors were those aged between 21 and 25 years. Only 22.3% of the blood donors were above 30 years. None of the 300 screened blood donors tested positive to HTLV-1 antibodies. Hence, the seroprevalence of HTLV-1 infection among blood donors was 0%. Of the blood donors, 5% had history of previous sexually transmitted disease, while 34.7% used condoms during sexual intercourse. Conclusion: The seroprevalence obtained in this study cannot statistically support the justification of routine screening of blood donors for HTLV-1 infection. More prospective and multicentered studies are required to determine the infectivity of HTLV-1 in blood donors in Nigeria. Keywords: retrovirus, transfusion, blood-borne infection, screening, Afric

Increased ex vivo cell death of central memory CD4 T cells in treated HIV infected individuals with unsatisfactory immune recovery

Abstract Background: High levels of ex vivo CD4 T-cell death and the accumulation of highly differentiated and/or immunosenescent T cells have been associated with poor CD4 T-cell recovery in treated HIV-infected individuals. However, the relationship between cell death and T-cell differentiation is still unclear. Methods: We have analyzed cell death, immunosenescence and differentiation parameters in HAART-treated subjects (VL <50 copies/mL for more than 2 years) with CD4 T-cell count <350 cells/μL (immunodiscordant, n = 23) or >400 cells/μL (immunoconcordant, n = 33). We included 11 healthy individuals as reference. Results: As expected, suboptimal CD4 T-cell recovery was associated with low frequencies of naïve cells, high frequencies of transitional and effector memory cells and a subsequent low ratio of central/transitional memory cells in the CD4 compartment. These alterations correlated with spontaneous CD4 T-cell death. A deeper analysis of cell death in CD4 T-cell subsets showed increased cell death in memory cells of immunodiscordant individuals, mainly affecting central memory cells. Immunosenescence was also higher in immunodiscordant individuals albeit unrelated to cell death. The CD8 compartment was similar in both HIV-infected groups, except for an underrepresentation of naïve cells in immunodiscordant individuals. Conclusion: Immunodiscordant individuals show alterations in memory CD4 T-cell differentiation associated with a short ex vivo lifespan of central memory cells and an in vivo low central/transitional memory cell ratio. These alterations may contribute to poor CD4 T-cell repopulation. Keywords: Immunodiscordant, Cell death, T-cell subsets, Immunosenescence, HAART, cAR