Potent Functional Antibody Responses Elicited by HIV-I DNA Priming and Boosting with Heterologous HIV-1 Recombinant MVA in Healthy Tanzanian Adults

Vaccine-induced HIV antibodies were evaluated in serum samples collected from healthy Tanzanian volunteers participating in a phase I/II placebo-controlled double blind trial using multi-clade, multigene HIV-DNA priming and recombinant modified vaccinia Ankara (HIV-MVA) virus boosting (HIVIS03). The HIV-DNA vaccine contained plasmids expressing HIV-1 gp160 subtypes A, B, C, Rev B, Gag A, B and RTmut B, and the recombinant HIV-MVA boost expressed CRF01_AE HIV-1 Env subtype E and Gag-Pol subtype A. While no neutralizing antibodies were detected using pseudoviruses in the TZM-bl cell assay, this prime-boost vaccination induced neutralizing antibodies in 83% of HIVIS03 vaccinees when a peripheral blood mononuclear cell (PBMC) assay using luciferase reporter-infectious molecular clones (LucR-IMC) was employed. The serum neutralizing activity was significantly (but not completely) reduced upon depletion of natural killer (NK) cells from PBMC (p=0.006), indicating a role for antibody-mediated Fcγ-receptor function. High levels of antibody-dependent cellular cytotoxicity (ADCC)-mediating antibodies against CRF01_AE and/or subtype B were subsequently demonstrated in 97% of the sera of vaccinees. The magnitude of ADCC-mediating antibodies against CM235 CRF01_AE IMC-infected cells correlated with neutralizing antibodies against CM235 in the IMC/PBMC assay. In conclusion, HIV-DNA priming, followed by two HIV-MVA boosts elicited potent ADCC responses in a high proportion of Tanzanian vaccinees. Our findings highlight the potential of HIV-DNA prime HIV-MVA boost vaccines for induction of functional antibody responses and suggest this vaccine regimen and ADCC studies as potentially important new avenues in HIV vaccine development.

Trial Registration

Controlled-Trials ISRCTN90053831 The Pan African Clinical Trials Registry ATMR2009040001075080 (currently PACTR2009040001075080)     

Inhibition of <Emphasis Type="Italic">Zizania latifolia</Emphasis> growth by <Emphasis Type="Italic">Phragmites australis</Emphasis>: an experimental study

The influence of Phragmites australis on the growth of Zizania latifolia, and the morphological characteristics of both species, were investigated at two nutrient levels. The experiment was carried out over three growing seasons between May 2003 and December 2005. The experimental plot was longitudinally divided into two equal halves, one of which was planted with Zizania latifolia (Zizania zone) and the other one with Phragmites australis (Phragmites zone). Four weeks after transplantation, the plot was again divided horizontally, perpendicular to the previous division, and subject to low (LN) and high nutrient (HN) treatments. Measured growth indices of the two species were more developed in the HN than in the LN treatments. Both species were observed to invade each other’s zone, but Phragmites latifolia seemed to out-compete Zizania latifolia individuals. This was evident from the decrease in below ground biomass of Zizania latifolia in the third growing season and deterioration in above ground organs with time. It was concluded that Phragmites australis out-competes Zizania latifolia due to better developed root and rhizome system.     

Test characteristics of urinary lipoarabinomannan and predictors of mortality among hospitalized HIV-infected tuberculosis suspects in Tanzania

Background

Tuberculosis is the most common cause of death among patients with HIV infection living in tuberculosis endemic countries, but many cases are not diagnosed pre-mortem. We assessed the test characteristics of urinary lipoarabinomannan (LAM) and predictors of mortality among HIV-associated tuberculosis suspects in Tanzania.

Methods

We prospectively enrolled hospitalized HIV-infected patients in Dar es Salaam, with ≥2 weeks of cough or fever, or weight loss. Subjects gave 2 mLs of urine to test for LAM using a commercially available ELISA, ≥2 sputum specimens for concentrated AFB smear and solid media culture, and 40 mLs of blood for culture.

Results

Among 212 evaluable subjects, 143 (68%) were female; mean age was 36 years; and the median CD4 count 86 cells/mm³. 69 subjects (33%) had culture confirmation of tuberculosis and 65 (31%) were LAM positive. For 69 cases of sputum or blood culture-confirmed tuberculosis, LAM sensitivity was 65% and specificity 86% compared to 36% and 98% for sputum smear. LAM test characteristics were not different in patients with bacteremia but showed higher sensitivity and lower specificity with decreasing CD4 cell count. Two month mortality was 64 (53%) of 121 with outcomes available. In multivariate analysis there was significant association of mortality with absence of anti-retroviral therapy (p = 0.004) and a trend toward association with a positive urine LAM (p = 0.16). Among culture-negative patients mortality was 9 (75%) of 12 in LAM positive patients and 27 (38%) of 71 in LAM negative patients (p = 0.02).

Conclusions

Urine LAM is more sensitive than sputum smear and has utility for the rapid diagnosis of culture-confirmed tuberculosis in this high-risk population. Mortality data raise the possibility that urine LAM may also be a marker for culture-negative tuberculosis.     

A study of dextran hydration in dilute,aqueous solution by the proton magnetic relaxation method

The times of proton magnetic relaxation in dilute (<1%), aqueous solutions of dextrans, having a molecular weight range of 17 x 10³?500 x 10³, are highly sensitive to the temperature—time prehistory of the samples investigated. Reliable results have been obtained only after preliminary heating of the solutions at 100° for 30 min. On the basis of the model of “two states of water in a solution”, the dependence of the degree of hydration of a dextran on its molecular weight has been obtained. In the molecular weight range 17 x 10³?110 x 10³, only a fraction of the D-glucose residues are hydrated, the degree of hydration increasing with the molecular weight. The data obtained are considered to be a consequence of intersegmentary interaction in a dextran macromolecule.     

Estimation of genetic parameters and prediction of breeding values for apple fruit-quality traits using pedigreed plant material in Europe

Genetic parameters for apple (Malus x domestica) fruit external traits (fruit size, ground colour, proportion of over colour and attractiveness) and sensory traits (firmness, crispness, texture, juiciness, flavour, sugar, acidity and global taste) were estimated using 2,207 pedigreed genotypes from breeding programmes in six European countries. Data were scored for 3 years and four periods during storage. Analyses were performed with a restricted maximum likelihood method using VCE 5.1.2 software. Heritability estimates ranged from medium to high for instrumental traits. Genetic correlations between firmness and sugar were medium and low between firmness and acidity. Sensory traits showed low to high heritability, acidity and flavour being, respectively, the most and the less heritable. Global taste was strongly correlated with texture, juiciness, and flavour and relatively less correlated with crispness and acidity. Sensory sugar and acidity showed highly negative correlations whereas their instrumental measurements showed low and increasing positive correlations from harvest to 4 months post-harvest. Sugar exhibited a higher sensory/instrumental divergence. Conversely, instrumental and sensory firmness were highly correlated. Fruit external characteristics had medium heritability. Fruit attractiveness had highest and lowest correlations with fruit size and ground colour, respectively. Best linear unbiased predictors of breeding values were computed for all genotypes with the software PEST. The results were analysed with regard to the dynamic and the reliability of genetic parameters according to the scoring dates. Original issues of the study and the importance of the obtained results for efficient designs of further apple fruit quality breeding programmes were discussed.     

Magnitude of functional CD8+ T-cell responses to the gag protein of human immunodeficiency virus type 1 correlates inversely with viral load in plasma

The importance of CD8+ T-cell responses in the control of human immunodeficiency virus type 1 (HIV-1) infection has been demonstrated, yet few studies have been able to correlate these responses with markers of HIV-1 disease progression. This study measured cell-mediated immune responses using peripheral blood mononuclear cells (PBMC) obtained from 27 patients with chronic HIV-1 infection, the majority of whom were off antiretroviral therapy. The ELISPOT assay was used to detect gamma interferon-secreting PBMC after stimulation with overlapping HIV-1 peptides spanning the Gag, Pol, Env, and Nef proteins in addition to the baculovirus-derived p24 and gp160 proteins. All volunteers had responses to at least one HIV-1-specific peptide. All but one of the subjects (96%) responded to the Gag peptide pool, and 86% responded to the Pol and/or Nef peptide pools. The magnitude and the breadth of T-cell responses directed to either the Gag or p24 peptide pools correlated inversely with viral load in plasma (r = -0.60, P < 0.001 and r = -0.52, P < 0.005, respectively) and directly with absolute CD4+ T-cell counts (r = 0.54, P < 0.01 and r = 0.39, P < 0.05, respectively) using the Spearman rank correlation test. Responses to the Pol and integrase peptide pools also correlated with absolute CD4+ T-cell counts (r = 0.45, P < 0.05 and r = 0.49, P < 0.01, respectively). No correlation with markers of disease progression was seen with specific T-cell responses directed toward the Env or Nef peptides. These data serve as strong evidence that major histocompatibility complex class I presentation of Gag peptides is an essential feature for any HIV-1 vaccine designed to elicit optimal CD8+ T-cell responses.     

Monte Carlo evaluation of particle interactions within the patient-dependent part of Elekta 6 MV photon beam applying IAEA phase space data

BackgroundThis work aims to provide a simulated method to be used by designers of medical accelerators and in clinical centers to manage and minimize particles’ interaction in the patient-dependent part of a 6 MV X-Ray Beam generated by the Elekta linear accelerator system, based on the latest GATE software version 9.0 Monte Carlo simulation, IAEA phase space data, and the last version of “Slurm” computing cluster.Materials and methodsThe experimental results are obtained using the Elekta 6 MV accelerator. The simulation MC developed includes the majority of the patient-dependent segments, such as Multi-Leaf Collimator (MLC), Tongue and Groove T&G, Rounded leaf Part, including the Jaws (XY). This model is used, with a simulated Iba Blue Phantom 2 homogeneous water phantom with dimensions 480 × 480 × 410 mm³, positioned at a Source-to-Surface-Distance (SSD) of 100 cm, all of the interactions of the mega voltage 6 MV radiations in water are simulated. The IAEA phase space (PS) provided by the International Atomic Energy Agency database and cluster computing (Slurm HPC-MARWAN, CNRST, Morocco) are employed to reduce our simulation time.ResultsThe results confirm that there are many interactions in all areas and the patient-dependent part’s internal structures. Thus, electrons and positrons participation appear in the generated field previously designed to be an X-ray beam. Besides, to validate our implementation geometry, the PDD’s and transverse profiles, at a depth ranging from 1.5 to 20 cm, for a field size of 10 × 10 cm², the beam quality such as D_10%, d_max (cm), d₈₀ (cm), TPR_(20/10), the two relative differences in dose were derived on σ_i and σ_i,max are calculated, respectively. Additionally, gamma index formalism for 2%/2 mm criteria is used. Once and for all, we typically take a good agreement between simulation MC GATE 9.0 and the experiment data with an error less than 2%/2 mm.ConclusionsIn the field of X-ray photons, a significant contribution of electrons and positrons has been found. This contribution could be enough to be essential or affect the delivered dose. A good agreement of 98% between this new approach of simulation MC GATE 9.0 software based on IAEA phase space and experimental dose distributions is observed regarding the validation tests used in this task.