Enzymatic Degradation of Star Poly(ε-Caprolactone) with Different Central Units.

Four-arm star poly(ε-caprolactone) with a central poly(ethylene glycol) PEG unit bridged with 2,2-bis(methyl) propionic acid, (PCL)2-b-PEG-b-(PCL)2, and six-arm star PCL homopolymer with a central dipentaerythritol units were hydrolysed using a lipase from Pseudomonas cepacia and the Thermobifida cellulosilytica cutinase Thc_Cut1. For comparative analysis, Y-shaped copolymers containing methylated PEG bridged with bisMPA, MePEG-(PCL)2, and linear triblock copolymers PCL-b-PEG-b-PCL were also subjected to enzymatic hydrolysis. The hydrophilic nature of the polymers was determined using contact angle analysis, showing that a higher PEG content exhibited a lower contact angle and higher surface wettability. Enzymatic hydrolysis was monitored by % mass loss, scanning electron microscopy (SEM), and differential scanning calorimetry (DSC). A higher rate of mass loss was found for lipase catalysed hydrolysis of those polymers with the highest PEG content, leading to significant surface erosion and increase in crystallinity within the first two days. Liquid chromatography (LC) and size exclusion chromatography (SEC) of samples incubated with the cutinase showed a significant decrease in molecular weight, increase in dispersity, and release of ε-CL monomer units after 6 h of incubation.

Decreasing Clostridium difficile health care-associated infections through use of a launderable mattress cover.

BACKGROUND: The annual incidence of Clostridium difficile infection (CDI) in the United States is estimated to be 330,000 cases. We evaluated the impact of using a launderable mattress and bed deck cover on the incidence of hospital-onset CDI in 2 long-term acute care hospitals (LTACHs). METHODS: Two LTACHs began using a launderable mattress and bed deck cover on beds starting in May 2013. One facility had 74 beds, and the other had 30 beds. Covers were changed after every patient. The covers were laundered using hot water, detergent, and chlorine. Rates for CDIs were compared using Poisson regression between the 16 months before use of the launderable cover and the 14 months after the cover started being used. RESULTS: At hospital A, the use of bedcovers reduced the rate of infection by 47.8% (95% confidence interval [CI], 47.1-48.6), controlling for the rate of handwashing compliance and length of stay in days. At hospital B, the use of bedcovers reduced the rate of infection by 50% (95% CI, 47.5-52.7), controlling for the rate of handwashing compliance and length of stay in days. CONCLUSION: The use of a launderable cover for mattresses and bed decks of hospital beds was associated with a decreased rate of health care-associated CDI in 2 LTACHs.

Suppression of major histocompatibility complex class II-associated invariant chain enhances the potency of an HIV gp120 DNA vaccine.

Summary One function of the major histocompatibility complex (MHC) class II-associated invariant chain (Ii) is to prevent MHC class II molecules from binding endogenously generated antigenic epitopes. Ii inhibition leads to MHC class II presentation of endogenous antigens by APC without interrupting MHC class I presentation. We present data that in vivo immunization of BALB/c mice with HIV gp120 cDNA plus an Ii suppressive construct significantly enhances the activation of both gp120-specific T helper (Th) cells and cytotoxic T lymphocytes (CTL). Our results support the concept that MHC class II-positive/Ii-negative (class II(+)/Ii(-)) antigen-presenting cells (APC) present endogenously synthesized vaccine antigens simultaneously by MHC class II and class I molecules, activating both CD4(+) and CD8(+) T cells. Activated CD4(+) T cells locally strengthen the response of CD8(+) CTL, thus enhancing the potency of a DNA vaccine.

Ii-Key/MHC class II epitope peptides as helper T cell vaccines for cancer and infectious disease.

Potent MHC class II antigenic peptide vaccines are created by covalently linking the N-terminus of a MHC class II epitope through a polymethylene bridge to the C-terminus of the Ii-Key segment of the Ii protein. Such hybrids enhance potency of presentation in vitro of the MHC class II epitope about 200 times relative to the epitope-only peptide. In vivo, as measured by IFN-gamma ELISPOT assays, the helper T cell response to vaccination is enhanced up to 8 times. The design of such hybrid vaccine peptides comes from insight into the mechanism of action of the Ii-Key motif within the Ii protein, in regulating antigenic peptide binding into the antigenic peptide binding groove of MHC class II molecules. Here we present the logic and experimental history of the development of these vaccine peptides, with particular attention to the hypothesized mechanism of action. Methods for the design and testing of these peptides are presented. Experience in developing peptide vaccines for immunotherapy of cancer is reviewed, focusing on the clinical potential of Ii-Key/MHC class II epitope hybrids.

Ii-Key/MHC class II epitope hybrids: a strategy that enhances MHC class II epitope loading to create more potent peptide vaccines.

Life-threatening diseases, such as cancer and pandemic influenza, demand new efforts towards effective vaccine design. Peptides represent a simple, safe and adaptable basis for vaccine development; however, the potency of peptide vaccines is insufficient in most cases for significant therapeutic efficacy. Several methods, such as Ligand Epitope Antigen Presentation System and ISCOMATRIX, have been developed to enhance the potency of peptide vaccines. One way of increasing the loading of MHC class II peptides occurs through the use of Ii-Key technology. Ii-Key (LRMK), a portion of the MHC class II-associated invariant chain (Ii), facilitates the direct loading of epitopes to the MHC class II molecule groove. Linking the Ii-Key moiety via a simple polymethylene bridge to an MHC class II epitope, to generate an Ii-Key/MHC class II epitope hybrid, greatly enhances the vaccine potency of the tethered epitope. The combination of such Ii-Key/MHC class II epitope hybrids with MHC class I epitope-containing peptides might generate a potent peptide vaccine for malignancies and infectious diseases. The Ii-Key hybrid technology is compared with other methods that enhance the potency of a peptide vaccine.

Generation of histocompatible tissues using nuclear transplantation.

Nuclear transplantation (therapeutic cloning) could theoretically provide a limitless source of cells for regenerative therapy. Although the cloned cells would carry the nuclear genome of the patient, the presence of mitochondria inherited from the recipient oocyte raises questions about the histocompatibility of the resulting cells. In this study, we created bioengineered tissues from cardiac, skeletal muscle, and renal cells cloned from adult bovine fibroblasts. Long-term viability was demonstrated after transplantation of the grafts into the nuclear donor animals. Reverse transcription-PCR (RT-PCR) and western blot analysis confirmed that the cloned tissues expressed tissue-specific mRNA and proteins while expressing a different mitochondrial DNA (mtDNA) haplotype. In addition to creating skeletal muscle and cardiac "patches", nuclear transplantation was used to generate functioning renal units that produced urinelike fluid and demonstrated unidirectional secretion and concentration of urea nitrogen and creatinine. Examination of the explanted renal devices revealed formation of organized glomeruli- and tubule-like structures. Delayed-type hypersensitivity (DTH) testing in vivo and Elispot analysis in vitro suggested that there was no rejection response to the cloned renal cells. The ability to generate histocompatible cells using cloning techniques addresses one of the major challenges in transplantation medicine.