Alemtuzumab is a monoclonal antibody that targets cell surface CD52 and is effective in depleting lymphocytes by cytolytic effects in vivo. Although the cytolytic effects of alemtuzumab are dependent ...on the density of CD52 antigen on cells, there is scant information regarding the expression levels of CD52 on different cell types. In this study, CD52 expression was assessed on phenotypically distinct subsets of lymphoid and myeloid cells in peripheral blood mononuclear cells (PBMCs) from normal donors. Results demonstrate that subsets of PBMCs express differing levels of CD52. Quantitative analysis showed that memory B cells and myeloid dendritic cells (mDCs) display the highest number while natural killer (NK) cells, plasmacytoid dendritic cells (pDCs) and basophils have the lowest number of CD52 molecules per cell amongst lymphoid and myeloid cell populations respectively. Results of complement dependent cytolysis (CDC) studies indicated that alemtuzumab mediated profound cytolytic effects on B and T cells with minimal effect on NK cells, basophils and pDCs, correlating with the density of CD52 on these cells. Interestingly, despite high CD52 levels, mDCs and monocytes were less susceptible to alemtuzumab-mediated CDC indicating that antigen density alone does not define susceptibility. Additional studies indicated that higher expression levels of complement inhibitory proteins (CIPs) on these cells partially contributes to their resistance to alemtuzumab mediated CDC. These results indicate that alemtuzumab is most effective in depleting cells of the adaptive immune system while leaving innate immune cells relatively intact.
Alemtuzumab is a humanized monoclonal antibody against CD52, an antigen found on the surface of normal and malignant lymphocytes. It is approved for the treatment of B-cell chronic lymphocytic ...leukaemia and is undergoing Phase III clinical trials for the treatment of multiple sclerosis. The exact mechanism by which alemtuzumab mediates its biological effects in vivo is not clearly defined and mechanism of action studies have been hampered by the lack of cross-reactivity between human and mouse CD52. To address this issue, a transgenic mouse expressing human CD52 (hCD52) was created. Transgenic mice did not display any phenotypic abnormalities and were able to mount normal immune responses. The tissue distribution of hCD52 and the level of expression by various immune cell populations were comparable to those seen in humans. Treatment with alemtuzumab replicated the transient increase in serum cytokines and depletion of peripheral blood lymphocytes observed in humans. Lymphocyte depletion was not as profound in lymphoid organs, providing a possible explanation for the relatively low incidence of infection in alemtuzumab-treated patients. Interestingly, both lymphocyte depletion and cytokine induction by alemtuzumab were largely independent of complement and appeared to be mediated by neutrophils and natural killer cells because removal of these populations with antibodies to Gr-1 or asialo-GM-1, respectively, strongly inhibited the activity of alemtuzumab whereas removal of complement by treatment with cobra venom factor had no impact. The hCD52 transgenic mouse appears to be a useful model and has provided evidence for the previously uncharacterized involvement of neutrophils in the activity of alemtuzumab.
Manipulation of the gut microbiota via fecal microbiota transplantation (FMT) has shown clinical promise in diseases such as recurrent Clostridioides difficile infection (rCDI). However, the variable ...nature of this approach makes it challenging to describe the relationship between fecal strain colonization, corresponding microbiota changes, and clinical efficacy. Live biotherapeutic products (LBPs) consisting of defined consortia of clonal bacterial isolates have been proposed as an alternative therapeutic class because of their promising preclinical results and safety profile. We describe VE303, an LBP comprising 8 commensal Clostridia strains under development for rCDI, and its early clinical development in healthy volunteers (HVs). In a phase 1a/b study in HVs, VE303 is determined to be safe and well-tolerated at all doses tested. VE303 strains optimally colonize HVs if dosed over multiple days after vancomycin pretreatment. VE303 promotes the establishment of a microbiota community known to provide colonization resistance.
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•Binary mixtures of extended surfactants and ethoxy sulfates are optimized for 300,000mg/L brine.•Proposed surfactant formulations meets IFT and stability criteria for cEOR.•The HLD ...method is found to be a promising tool for designing microemulsion systems for cEOR applications.•Correct K-values and αT values of surfactants play a crucial role in an accuracy of the HLD method.
In this work, alcohol-free surfactant formulations incorporating sodium alkyl alkoxy sulfate surfactants and a sodium alkyl ethoxy sulfate surfactant are tested at 52°C for reservoir brine having a total dissolved solids of above 300,000mg/L with total hardness of about 13,000mg/L. The optimized surfactant formulations show excellent aqueous phase stability, produce an ultra-low-interfacial tension (IFT) of 0.004mN/m, and give fast coalescence rates of less than 30min at reservoir salinity and temperature. Surfactant-only sand pack studies further validate the formulations by mobilizing about 60% of residual oil without mobility control. In addition, the hydrophilic lipophilic deviation (HLD) method is used to find the optimal surfactant/co-surfactant ratio (defined as the ratio giving the lowest IFT) at the reservoir salinity and temperature. Results show, first, that HLD constants measure at low salinity are applicable at high salinity and high hardness, and second, that the correct determination of surfactant head constant ‘K’ and temperature constant ‘αT’ governs the precision of the HLD approach as a surfactant selection tool for chemical enhanced oil recovery (cEOR) application. Results illustrate the potential of surfactant-only flooding to produce significant tertiary oil recovery.
A prototype reusable large-volume (2 mL) autoinjector (LVAI) was designed to compare injection performance of a novel 27 gauge ultra-thin wall (UTW) pre-filled syringe (PFS) cannula (8 mm external ...cannula length, 14.4 mm total needle length) against an existing 27 gauge special thin wall (STW) PFS cannula (12.7 mm external cannula length, 19 mm total needle length) across a range of injectate viscosities (2.3-30 cP) in a series of in vivo feasibility studies in swine. The UTW cannula had an approximately 30% greater cross-sectional lumen area than the STW cannula. The target exposed needle length was adjusted to ensure appropriate needle penetration depth and achieve injectate deposition in the subcutaneous (SC) tissue. Delivery time and volume, injection site leakage, injectate depot location, and local tissue effects were examined. The STW and UTW cannulae both provided effective SC delivery of contrast placebo solutions, and were able to accommodate injectate viscosity up to 30 cP without quantifiable leakage from the tissue and with minor tissue effects which resolved within 1-2 hours. Delivery times at each viscosity were significantly different between PFS types with the UTW PFS producing faster delivery times. In a histological substudy of the UTW cannula using injectate viscosities up to 50 cP, injection site reactions were rare and, when present, were of minimal severity. This series of studies demonstrates the feasibility of LVAI SC injection and informs autoinjector and PFS design considerations. Use of a UTW cannula may enable more rapid LVAI injections with minimal tissue effects, especially for higher viscosity formulations.
Many current subcutaneous (SC) biologic therapies may require >1 mL volume or have increased viscosity, necessitating new delivery system approaches. This study evaluated 2-mL large-volume ...autoinjector (LVAI) delivery performance across varying solution viscosities and design inputs to assess the design space and identify configurations that produce practical injection times.
Investigational LVAI delivery duration and volume, depot location, and tissue effects were examined in both air and in vivo models across various pre-filled syringe (PFS) cannula types (27 G Ultra-thin wall UTW, 27 G special thin wall STW, or 29 G thin-wall TW), drive spring forces (SF
LOW
or SF
HIGH
), and Newtonian solutions (2.3-50 centipoise cP).
Within each design configuration, increasing PFS internal diameters and spring forces reduced delivery times, while increasing viscosity increased times. The 27 G UTW PFS/SF
HIGH
combination achieved shorter delivery times across all injection conditions, with 2 mL in vivo durations <15 seconds at ≤31 cP and routinely <20 seconds at 39 and 51 cP, with nominal and transitory tissue effects.
PFS cannula and spring force combinations can be tailored to achieve various injection durations across viscosities, while UTW PFS enables faster rates to potentially better accommodate human factors during LVAI injection, especially at high viscosity.
Background:
Limited published data exists quantifying the influence of human factors (HF) and pen needle (PN) design on delivery outcomes of pen injection systems. This preclinical in vivo study ...examines the impact of PN hub design and applied force against the skin during injection on needle penetration depth (NPD).
Method:
To precisely locate injection depth, PN injections (20 µl; 2 IU, U-100 volume equivalent) of iodinated contrast agent were administered to the flank of Yorkshire swine across a range of clinically relevant application forces against the skin (0.25, 0.75, 1.25, and 2.0 lbf). The NPD, representing in vivo needle tip depth in SC tissue, from four 32 G × 4 mm PN devices (BD Nano™ 2nd Gen and three commercial posted-hub PN devices; n = 75/device/force, 1200 total) was measured by fluoroscopic imaging of the resulting depot.
Results:
The reengineered hub design more closely achieved the 4 mm target NPD with significantly less variability (P = .006) than commercial posted-hub PN devices across the range of applied injection forces. Calculations of IM (intramuscular) injection risk completed through in silico probability model, using NPD and average human tissue thickness measurements, displayed a commensurate reduction (~2-8x) compared to conventional PN hub designs.
Conclusions:
Quantifiable differences in injection depth were observed between identical labeled length PN devices indicating that hub design features, coupled with aspects of variable injection technique, may influence injection depth accuracy and consistency. The reengineered hub design may reduce the impact of unintended individual technique differences by improving target injection depth consistency and reducing IM injection potential.
The past decade has seen tremendous advances in both our understanding of cancer immunosuppressive microenvironments and colonic bacteria facilitated by immune checkpoint inhibitor antibodies and ...next generation sequencing, respectively. Because an important role of the host immune system is to communicate with and regulate the gut microbial community, it should not come as a surprise that the behavior of one is coupled to the other. In this review, we will attempt to dissect some of the studies demonstrating cancer immunotherapy modulation by specific gut microbes and discuss possible molecular mechanisms for this effect.
Abstract Alemtuzumab is a monoclonal antibody against the CD52 antigen present at high levels on the surface of lymphocytes. While treatment of multiple sclerosis patients with alemtuzumab results in ...marked depletion of lymphocytes from the circulation, it has not been associated with a high incidence of serious infections. In a human CD52 transgenic mouse, alemtuzumab treatment showed minimal impact on the number and function of innate immune cells. A transient decrease in primary adaptive immune responses was observed post-alemtuzumab but there was little effect on memory responses. These results potentially help explain the level of immunocompetence observed in alemtuzumab-treated MS patients.
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