Attacking Latent HIV with convertibleCAR-T Cells, a Highly Adaptable Killing Platform.

Current approaches to reducing the latent HIV reservoir entail first reactivating virus-containing cells to become visible to the immune system. A critical second step is killing these cells to reduce reservoir size. Endogenous cytotoxic T-lymphocytes (CTLs) may not be adequate because of cellular exhaustion and the evolution of CTL-resistant viruses. We have designed a universal CAR-T cell platform based on CTLs engineered to bind a variety of broadly neutralizing anti-HIV antibodies. We show that this platform, convertibleCAR-T cells, effectively kills HIV-infected, but not uninfected, CD4 T cells from blood, tonsil, or spleen and only when armed with anti-HIV antibodies. convertibleCAR-T cells also kill within 48 h more than half of the inducible reservoir found in blood of HIV-infected individuals on antiretroviral therapy. The modularity of convertibleCAR-T cell system, which allows multiplexing with several anti-HIV antibodies yielding greater breadth and control, makes it a promising tool for attacking the latent HIV reservoir.

Psychiatric Hospitalization and Length of Stay Differences in Cannabis Users and Non-Users with a Primary Discharge Diagnosis of Schizophrenia or Schizoaffective Disorder.

BACKGROUND: The effects of cannabis use in vulnerable persons with schizophrenia or schizoaffective disorder, continues to be elucidated. METHODS: We compared 55 cannabis-only users (Group 1) with 462 non-substance users (Group 2) on measures of length of stay and number of psychiatric hospitalizations with a primary discharge diagnosis of schizophrenia or schizoaffective disorder using the Wilcoxon-Mann-Whitney non-parametric test for non-normal distributions, analysis of variance (ANOVA), and Poisson regression analysis. RESULTS: Group 1 had a mean length of stay of 6.15 days (sd = 5.32 days) and Group 2 had a mean length of stay of 8.66 days (sd = 11.14 days) (i.e. Wilcoxon-Mann-Whitney, p = .0347; log-transformed ANOVA, p = .0203). This difference was no longer statistically significant when controlling for three covariates (p = .1543). Poisson regressions for the mean number of admissions (1.84) were not statistically significant. CONCLUSIONS: Cannabis use may not be a good predictor of length of stay, once covariates are considered, and mean number of hospitalizations in hospitalized patients with schizophrenia or schizoaffective disorder.

Protein aggregate turbidity: Simulation of turbidity profiles for mixed-aggregation reactions.

Due to their colloidal nature, all protein aggregates scatter light in the visible wavelength region when formed in aqueous solution. This phenomenon makes solution turbidity, a quantity proportional to the relative loss in forward intensity of scattered light, a convenient method for monitoring protein aggregation in biochemical assays. Although turbidity is often taken to be a linear descriptor of the progress of aggregation reactions, this assumption is usually made without performing the necessary checks to provide it with a firm underlying basis. In this article, we outline utilitarian methods for simulating the turbidity generated by homogeneous and mixed-protein aggregation reactions containing fibrous, amorphous, and crystalline structures. The approach is based on a combination of Rayleigh-Gans-Debye theory and approximate forms of the Mie scattering equations.

Novel high-molecular-weight, R-type bacteriocins of Clostridium difficile.

Clostridium difficile causes one of the leading nosocomial infections in developed countries, and therapeutic choices are limited. Some strains of C. difficile produce phage tail-like particles upon induction of the SOS response. These particles have bactericidal activity against other C. difficile strains and can therefore be classified as bacteriocins, similar to the R-type pyocins of Pseudomonas aeruginosa. These R-type bacteriocin particles, which have been purified from different strains, each have a different C. difficile-killing spectrum, with no one bacteriocin killing all C. difficile isolates tested. We have identified the genetic locus of these "diffocins" (open reading frames 1359 to 1376) and have found them to be common among the species. The entire diffocin genetic locus of more than 20 kb was cloned and expressed in Bacillus subtilis, and this resulted in production of bactericidal particles. One of the interesting features of these particles is a very large structural protein of ~200 kDa, the product of gene 1374. This large protein determines the killing spectrum of the particles and is likely the receptor-binding protein. Diffocins may provide an alternate bactericidal agent to prevent or treat infections and to decolonize individuals who are asymptomatic carriers.

An Escherichia coli O157-specific engineered pyocin prevents and ameliorates infection by E. coli O157:H7 in an animal model of diarrheal disease.

AvR2-V10.3 is an engineered R-type pyocin that specifically kills Escherichia coli O157, an enteric pathogen that is a major cause of food-borne diarrheal disease. New therapeutics to counteract E. coli O157 are needed, as currently available antibiotics can exacerbate the consequences of infection. We show here that orogastric administration of AvR2-V10.3 can prevent or ameliorate E. coli O157:H7-induced diarrhea and intestinal inflammation in an infant rabbit model of infection when the compound is administered either in a postexposure prophylactic regimen or after the onset of symptoms. Notably, administration of AvR2-V10.3 also reduces bacterial carriage and fecal shedding of this pathogen. Our findings support the further development of pathogen-specific R-type pyocins as a way to treat enteric infections.

Rapid and sustained improvement in treatment-refractory depression through use of acute intravenous ketamine and concurrent transdermal selegiline: A case series.

BACKGROUND: Treatment resistant depression is a significant source of morbidity and mortality. For patients having failed or unable to undergo the electroconvulsive therapy procedure few effective alternative treatments exist. METHODS: A case series is presented where six patients with treatment resistant depression failing both electroconvulsive therapy and oral antidepressants are concomitantly treated with short course intravenous ketamine and longer term selegiline transdermal system. RESULTS: All six patients experienced clinical improvement with intravenous ketamine, with resolution of suicidality, increased food intake, and commitment to treatment adherence. Five patients showed sustained improvement with the selegiline transdermal system. One patient discontinued selegiline after developing peripheral edema and palpitations. LIMITATIONS: This case series included only patients experiencing moderate to severe treatment resistant depression. Availability of long-term follow-up data not available in some cases. CONCLUSION: Intravenous ketamine with simultaneous administration of the selegiline transdermal system is one strategy for treating treatment resistant depression in patients having failed or unable to undergo the electroconvulsive therapy procedure.

convertibleCARs: A chimeric antigen receptor system for flexible control of activity and antigen targeting.

We have developed a chimeric antigen receptor (CAR) platform that functions as a modular system to address limitations of traditional CAR therapies. An inert form of the human NKG2D extracellular domain (iNKG2D) was engineered as the ectodomain of the CAR to generate convertibleCARTM-T cells. These cells were specifically directed to kill antigen-expressing target cells only in the presence of an activating bispecific adapter comprised of an iNKG2D-exclusive ULBP2-based ligand fused to an antigen-targeting antibody (MicAbodyTM). Efficacy against Raji tumors in NSG mice was dependent upon doses of both a rituximab-based MicAbody and convertibleCAR-T cells. We have also demonstrated that the exclusive ligand-receptor partnering enabled the targeted delivery of a mutant form of IL-2 to selectively promote the expansion of convertibleCAR-T cells in vitro and in vivo. By altering the Fv domains of the MicAbody or the payload fused to the orthogonal ligand, convertibleCAR-T cells can be readily targeted or regulated.

Retargeting R-type pyocins to generate novel bactericidal protein complexes.

R-type pyocins are high-molecular-weight bacteriocins that resemble bacteriophage tail structures and are produced by some Pseudomonas aeruginosa strains. R-type pyocins kill by dissipating the bacterial membrane potential after binding. The high-potency, single-hit bactericidal kinetics of R-type pyocins suggest that they could be effective antimicrobials. However, the limited antibacterial spectra of natural R-type pyocins would ultimately compromise their clinical utility. The spectra of these protein complexes are determined in large part by their tail fibers. By replacing the pyocin tail fibers with tail fibers of Pseudomonas phage PS17, we changed the bactericidal specificity of R2 pyocin particles to a different subset of P. aeruginosa strains, including some resistant to PS17 phage. We further extended this idea by fusing parts of R2 tail fibers with parts of tail fibers from phages that infect other bacteria, including Escherichia coli and Yersinia pestis, changing the killing spectrum of pyocins from P. aeruginosa to the bacterial genus, species, or strain that serves as a host for the donor phage. The assembly of active R-type pyocins requires chaperones specific for the C-terminal portion of the tail fiber. Natural and retargeted R-type pyocins exhibit narrow bactericidal spectra and thus can be expected to cause little collateral damage to the healthy microbiotae and not to promote the horizontal spread of multidrug resistance among bacteria. Engineered R-type pyocins may offer a novel alternative to traditional antibiotics in some infections.

The Wandering Woman: A Case Study of Catatonia vs Factitious Disorder.

A 61-year-old woman with an unknown psychiatric history presented with mutism, stupor, negativism, and withdrawn behavior. She was admitted to the psychiatric unit for what appeared to be catatonia. Medical records were not readily available. A comprehensive evaluation did not uncover any medical etiology. Lorazepam was ineffective at consistently reversing her catatonic symptoms. During week three of hospitalization, she was given olanzapine with subsequent improvement in her negativism. Several physicians believed her catatonic symptoms were feigned given multiple episodes of spontaneous purposeful movement when she was not under the direct supervision of staff. There is minimal literature on distinguishing catatonia and factitious disorder. This distinction is crucial because these diagnoses require very different treatments, and the iatrogenic complications related to the treatment of catatonia with high-dose benzodiazepines and electroconvulsive therapy are significant. Rapid access to electronic health records can facilitate treatment for patients who cannot provide a medical history, especially when factitious disorder is included in the differential diagnosis.

Bacteriophage SP6 encodes a second tailspike protein that recognizes Salmonella enterica serogroups C2 and C3.

SP6 is a salmonella phage closely related to coliphage K1-5. K1-5 is notable in that it encodes two polysaccharide-degrading tailspike proteins, an endosialidase that allows it to infect E. coli K1, and a lyase that enables it to infect K5 strains. SP6 is similar to K1-5 except that it encodes a P22-like endorhamnosidase tailspike, gp46, allowing it to infect group B Salmonella. We show here that SP6 can also infect Salmonella serogroups C2 and C3 and that a mutation in a putative second tailspike, gp47, eliminates this specificity. Gene 47 was fused to the coding region of the N-terminal portion of the Pseudomonas aeruginosa R2 pyocin tail fiber and expressed in trans such that the fusion protein becomes incorporated into pyocin particles. These pyocins, termed AvR2-SP47, killed serogroups C2 and C3Salmonella. We conclude that SP6 encodes two tail proteins providing it a broad host range among Salmonella enterica.

Dissecting and designing inhibitor selectivity determinants at the S1 site using an artificial Ala190 protease (Ala190 uPA).

A site-directed mutant of the serine protease urokinase-type plasminogen activator (uPA), was produced to assess the contribution of the Ser190 side-chain to the affinity and selectivity of lead uPA inhibitors in the absence of other differences present in comparisons of natural proteases. Crystallography and enzymology involving WT and Ala190 uPA were used to calculate free energy binding contributions of hydrogen bonds involving the Ser190 hydroxyl group (O(gamma)(Ser190)) responsible for the remarkable selectivity of 6-halo-5-amidinoindole and 6-halo-5-amidinobenzimidazole inhibitors toward uPA and against natural Ala190 protease anti-targets. Crystal structures of uPA complexes of novel, active site-directed arylguanidine and 2-aminobenzimidazole inhibitors of WT uPA, together with associated K(i) values for WT and Ala190 uPA, also indicate a significant role of Ser190 in the binding of these classes of uPA inhibitors. Structures and associated K(i) values for a lead inhibitor (CA-11) bound to uPA and to five other proteases, as well as for other leads bound to multiple proteases, help reveal the features responsible for the potency (K(i)=11nM) and selectivity of the remarkably small inhibitor, CA-11. The 6-fluoro-5-amidinobenzimidzole, CA-11, is more than 1000-fold selective against natural Ala190 protease anti-targets, and more than 100-fold selective against other Ser190 anti-targets.

Genome sequence of E. coli O104:H4 leads to rapid development of a targeted antimicrobial agent against this emerging pathogen.

A recent widespread outbreak of Escherichia coli O104:H4 in Germany demonstrates the dynamic nature of emerging and re-emerging food-borne pathogens, particularly STECs and related pathogenic E. coli. Rapid genome sequencing and public availability of these data from the German outbreak strain allowed us to identify an O-antigen-specific bacteriophage tail spike protein encoded in the genome. We synthesized this gene and fused it to the tail fiber gene of an R-type pyocin, a phage tail-like bacteriocin, and expressed the novel bacteriocin such that the tail fiber fusion was incorporated into the bacteriocin structure. The resulting particles have bactericidal activity specifically against E. coli strains that produce the O104 lipopolysaccharide antigen, including the outbreak strain. This O-antigen tailspike-R-type pyocin strategy provides a platform to respond rapidly to emerging pathogens upon the availability of the pathogen's genome sequence.

Expression, crystallization, and three-dimensional structure of the catalytic domain of human plasma kallikrein.

Plasma kallikrein is a serine protease that has many important functions, including modulation of blood pressure, complement activation, and mediation and maintenance of inflammatory responses. Although plasma kallikrein has been purified for 40 years, its structure has not been elucidated. In this report, we described two systems (Pichia pastoris and baculovirus/Sf9 cells) for expression of the protease domain of plasma kallikrein, along with the purification and high resolution crystal structures of the two recombinant forms. In the Pichia pastoris system, the protease domain was expressed as a heterogeneously glycosylated zymogen that was activated by limited trypsin digestion and treated with endoglycosidase H deglycosidase to reduce heterogeneity from the glycosylation. The resulting protein was chromatographically resolved into four components, one of which was crystallized. In the baculovirus/Sf9 system, homogeneous, crystallizable, and nonglycosylated protein was expressed after mutagenizing three asparagines (the glycosylation sites) to glutamates. When assayed against the peptide substrates, pefachrome-PK and oxidized insulin B chain, both forms of the protease domain were found to have catalytic activity similar to that of the full-length protein. Crystallization and x-ray crystal structure determination of both forms have yielded the first three-dimensional views of the catalytic domain of plasma kallikrein. The structures, determined at 1.85 A for the endoglycosidase H-deglycosylated protease domain produced from P. pastoris and at 1.40 A for the mutagenically deglycosylated form produced from Sf9 cells, show that the protease domain adopts a typical chymotrypsin-like serine protease conformation. The structural information provides insights into the biochemical and enzymatic properties of plasma kallikrein and paves the way for structure-based design of protease inhibitors that are selective either for or against plasma kallikrein.