40 research outputs found
Unique CRF01_AE Gag CTL Epitopes Associated with Lower HIV-Viral Load and Delayed Disease Progression in a Cohort of HIV-Infected Thais
Cytotoxic T Lymphocytes (CTLs) play a central role in controlling HIV-replication. Although numerous CTL epitopes have been described, most are in subtype B or C infection. Little is known about CTL responses in CRF01_AE infection. Gag CTL responses were investigated in a cohort of 137 treatment-naïve HIV-1 infected Thai patients with high CD4+ T cell counts, using gIFN Enzyme-Linked Immunospot (ELISpot) assays with 15-mer overlapping peptides (OLPs) derived from locally dominant CRF01_AE Gag sequences. 44 OLPs were recognized in 112 (81.8%) individuals. Both the breadth and magnitude of the CTL response, particularly against the p24 region, positively correlated with CD4+ T cell count and inversely correlated with HIV viral load. The breadth of OLP response was also associated with slower progression to antiretroviral therapy initiation. Statistical analysis and single peptide ELISpot assay identified at least 17 significant associations between reactive OLP and HLA in 12 OLP regions; 6 OLP-HLA associations (35.3%) were not compatible with previously reported CTL epitopes, suggesting that these contained new CTL Gag epitopes. A substantial proportion of CTL epitopes in CRF01_AE infection differ from subtype B or C. However, the pattern of protective CTL responses is similar; Gag CTL responses, particularly against p24, control viral replication and slow clinical progression
CTL Escape Mediated by Proteasomal Destruction of an HIV-1 Cryptic Epitope
Cytotoxic CD8+ T cells (CTLs) play a critical role in controlling viral
infections. HIV-infected individuals develop CTL responses against epitopes
derived from viral proteins, but also against cryptic epitopes encoded by viral
alternative reading frames (ARF). We studied here the mechanisms of HIV-1 escape
from CTLs targeting one such cryptic epitope, Q9VF, encoded by an
HIVgag ARF and presented by HLA-B*07. Using PBMCs of
HIV-infected patients, we first cloned and sequenced proviral DNA encoding for
Q9VF. We identified several polymorphisms with a minority of proviruses encoding
at position 5 an aspartic acid (Q9VF/5D) and a majority encoding an asparagine
(Q9VF/5N). We compared the prevalence of each variant in PBMCs of
HLA-B*07+ and HLA-B*07- patients. Proviruses encoding Q9VF/5D were
significantly less represented in HLA-B*07+ than in HLA-B*07-
patients, suggesting that Q9FV/5D encoding viruses might be under selective
pressure in HLA-B*07+ individuals. We thus analyzed ex
vivo CTL responses directed against Q9VF/5D and Q9VF/5N. Around
16% of HLA-B*07+ patients exhibited CTL responses targeting Q9VF
epitopes. The frequency and the magnitude of CTL responses induced with Q9VF/5D
or Q9VF/5N peptides were almost equal indicating a possible cross-reactivity of
the same CTLs on the two peptides. We then dissected the cellular mechanisms
involved in the presentation of Q9VF variants. As expected, cells infected with
HIV strains encoding for Q9VF/5D were recognized by Q9VF/5D-specific CTLs. In
contrast, Q9VF/5N-encoding strains were neither recognized by Q9VF/5N- nor by
Q9VF/5D-specific CTLs. Using in vitro proteasomal digestions
and MS/MS analysis, we demonstrate that the 5N variation introduces a strong
proteasomal cleavage site within the epitope, leading to a dramatic reduction of
Q9VF epitope production. Our results strongly suggest that HIV-1 escapes CTL
surveillance by introducing mutations leading to HIV ARF-epitope destruction by
proteasomes
Estrus cyclicity of spinogenesis: underlying mechanisms
Hippocampal spine density varies with the estrus cycle. The cyclic change in estradiol levels in serum was hypothesized to underlie this phenomenon, since treatment of ovariectomized animals with estradiol induced an increase in spine density in hippocampal dendrites of rats, as compared to ovariectomized controls. In contrast, application of estradiol to hippocampal slice cultures did not promote spinogenesis. In addressing this discrepancy, we found that hippocampal neurons themselves are capable of synthesizing estradiol de novo. Estradiol synthesis can be suppressed by aromatase inhibitors and by knock-down of Steroid Acute Regulatory Protein (StAR) and enhanced by substrates of steroidogenesis. Expression of estrogen receptors (ERs) and synaptic proteins, synaptogenesis, and long-term potentiation (LTP) correlated positively with aromatase activity in hippocampal cultures without any difference between genders. All effects due to inhibition of aromatase activity were rescued by application of estradiol to the cultures. Most importantly, gonadotropin-releasing hormone (GnRH) increased estradiol synthesis dose-dependently via an aromatase-mediated mechanism and consistently increased spine synapse density and spinophilin expression. As a consequence, our data suggest that cyclic fluctuations in spine synapse density result from pulsative release of GnRH from the hypothalamus and its effect on hippocampal estradiol synthesis, rather than from varying levels of serum estradiol. This hypothesis is further supported by higher GnRH receptor (GnRH-R) density in the hippocampus than in the cortex and hypothalamus and the specificity of estrus cyclicity of spinogenesis in the hippocampus, as compared to the cortex
Evolutionarily Conserved Protein Sequences of Influenza A Viruses, Avian and Human, as Vaccine Targets
10.1371/journal.pone.0001190PLoS ONE21
Prevention of acute kidney injury and protection of renal function in the intensive care unit
Acute renal failure on the intensive care unit is associated with significant mortality and morbidity. To determine recommendations for the prevention of acute kidney injury (AKI), focusing on the role of potential preventative maneuvers including volume expansion, diuretics, use of inotropes, vasopressors/vasodilators, hormonal interventions, nutrition, and extracorporeal techniques. A systematic search of the literature was performed for studies using these potential protective agents in adult patients at risk for acute renal failure/kidney injury between 1966 and 2009. The following clinical conditions were considered: major surgery, critical illness, sepsis, shock, and use of potentially nephrotoxic drugs and radiocontrast media. Where possible the following endpoints were extracted: creatinine clearance, glomerular filtration rate, increase in serum creatinine, urine output, and markers of tubular injury. Clinical endpoints included the need for renal replacement therapy, length of stay, and mortality. Studies are graded according to the international Grades of Recommendation, Assessment, Development, and Evaluation (GRADE) group system Several measures are recommended, though none carries grade 1A. We recommend prompt resuscitation of the circulation with special attention to providing adequate hydration whilst avoiding high-molecular-weight hydroxy-ethyl starch (HES) preparations, maintaining adequate blood pressure using vasopressors in vasodilatory shock. We suggest using vasopressors in vasodilatory hypotension, specific vasodilators under strict hemodynamic control, sodium bicarbonate for emergency procedures administering contrast media, and periprocedural hemofiltration in severe chronic renal insufficiency undergoing coronary intervention
Antitumor effect of protein-bound polysaccharide preparation, ps-k, against 3-methylcholanthrene-induced fibrosarcoma in c57bl/6 mice.
Effect of protein-bound polysaccharide preparation, ps-k, on the immune response of mice to sheep red blood cells.
Cognitive deficits in Calsyntenin-2 deficient mice associated with reduced GABAergic transmission
Calsyntenin-2 has an evolutionarily conserved role in cognition. In a human genome-wide screen, the CLSTN2 locus was associated with verbal episodic memory, and expression of human calsyntenin-2 rescues the associative learning defect in orthologous Caenorhabditis elegans mutants. Other calsyntenins promote synapse development, calsyntenin-1 selectively of excitatory synapses and calsyntenin-3 of excitatory and inhibitory synapses. We found that targeted deletion of calsyntenin-2 in mice results in a selective reduction in functional inhibitory synapses. Reduced inhibitory transmission was associated with a selective reduction of parvalbumin interneurons in hippocampus and cortex. Clstn2(−/−) mice showed normal behavior in elevated plus maze, forced swim test, and novel object recognition assays. However, Clstn2(−/−) mice were hyperactive in the open field and showed deficits in spatial learning and memory in the Morris water maze and Barnes maze. These results confirm a function for calsyntenin-2 in cognitive performance and indicate an underlying mechanism that involves parvalbumin interneurons and aberrant inhibitory transmission