Assessment of Skin Toxicity in an in Vitro Reconstituted Human Epidermis Model Using Deep Learning

Skin toxicity is a common safety concern associated with drugs that inhibit epidermal growth factor receptors as well as other targets involved in epidermal growth and differentiation. Recently, the use of a three-dimensional reconstructed human epidermis model enabled large-scale drug screening and showed potential for predicting skin toxicity. Although a decrease in epidermal thickness was often observed when the three-dimensional reconstructed tissues were exposed to drugs causing skin toxicity, the thickness evaluation of epidermal layers from a pathologist was subjective and not easily reproducible or scalable. In addition, the subtle differences in thickness among tissues, as well as the large number of samples tested, made cross-study comparison difficult when a manual evaluation strategy was used. The current study used deep learning and image-processing algorithms to measure the viable epidermal thickness from multiple studies and found that the measured thickness was not only significantly correlated with a pathologist's semi-quantitative evaluation but was also in close agreement with the quantitative measurement performed by pathologists. Moreover, a sensitivity of 0.8 and a specificity of 0.75 were achieved when predicting the toxicity of 18 compounds with clinical observations with these epidermal thickness algorithms. This approach is fully automated, reproducible, and highly scalable. It not only shows reasonable accuracy in predicting skin toxicity but also enables cross-study comparison and high-throughput compound screening.

Assessment of rat polyclonal antisera's suitability in hemagglutination inhibition assay for influenza surveillance and antigenic mapping

This paper presents comparative hemagglutination inhibition (HI) assay data obtained using ferret or rat antisera to analyze influenza viruses. The results indicate that rat antisera can be successfully applied both for identification and for antigenic analysis of human influenza A and B viruses. Data gained with rat antisera were comparable to those obtained with ferret antisera. In-depth statistical analysis, based on Confusion Matrix analysis and Receiver Operating Characteristic (ROC) analysis, confirmed good coincidence between ferret antisera-based and rat antisera-based results. Two-dimensional antigenic mapping, based on HI assays using rat and ferret antisera, supported these findings. Both antisera types yielded identical antigenic attributions for the viruses analyzed, and both permitted visualization of contemporary human influenza virus evolutionary trends.

Randomized Phase I Healthy Volunteer Study of UTTR1147A (IL-22Fc): A Potential Therapy for Epithelial Injury

Most treatments for epithelial injury target hematopoietic mechanisms, possibly causing immunosuppression. Interleukin (IL)-22 promotes tissue regeneration, acting directly on epithelial cells. UTTR1147A, a human IL-22Fc (immunoglobulin G (IgG)4) fusion protein, activates IL-22 signaling. This phase I placebo-controlled trial of single, ascending, i.v. (1-120 μg/kg) and s.c (3-120 μg/kg) doses of UTTR1147A analyzed its effects on safety, tolerability, pharmacokinetics, and pharmacodynamic biomarkers in healthy volunteers. Most adverse events (AEs) were mild or moderate. The maximum tolerated i.v. dose in healthy volunteers was 90 μg/kg. Predominant AEs were dose-dependent reversible skin effects consistent with IL-22 pharmacology. UTTR1147A exposure increased approximately dose-proportionally, with a half-life of ~1 week. IL-22 biomarkers (regenerating islet protein 3A (REG3A), serum amyloid A (SAA), and C-reactive protein (CRP)) increased dose-dependently. Neither inflammatory symptoms and signs nor cytokines increased with CRP elevations. UTTR1147A demonstrated acceptable safety, pharmacokinetics, and IL-22R engagement, supporting further clinical development.

Nonclinical safety assessment of a human interleukin-22FC IG fusion protein demonstrates in vitro to in vivo and cross-species translatability

Although Interleukin-22 (IL-22) is produced by various leukocytes, it preferentially targets cells with epithelial origins. IL-22 exerts essential roles in modulating various tissue epithelial functions, such as innate host defense against extracellular pathogens, barrier integrity, regeneration, and wound healing. Therefore, IL-22 is thought to have therapeutic potential in treating diseases associated with infection, tissue injury or chronic tissue damage. A number of in vitro and in vivo nonclinical studies were conducted to characterize the pharmacological activity and safety parameters of UTTR1147A, an IL-22 recombinant fusion protein that links the human cytokine IL-22 with the Fc portion of a human immunoglobulin. To assess the pharmacological activity of UTTR1147A, STAT3 activation was evaluated in primary hepatocytes isolated from human, cynomolgus monkey, minipig, rat, and mouse after incubation with UTTR1147A. UTTR1147A activated STAT3 in all species evaluated, demonstrating that all were appropriate nonclinical species for toxicology studies. The nonclinical safety profile of UTTR1147A was evaluated in rats, minipigs, and cynomolgus monkeys to establish a safe clinical starting dose for humans in Phase I trials and to support clinical intravenous, subcutaneous and/or topical administration treatment regimen. Results demonstrate the cross-species translatability of the biological response in activating the IL-22 pathway as well as the translatability of findings from in vitro to in vivo systems. UTTR1147A was well tolerated in all species tested and induced the expected pharmacologic effects of epidermal hyperplasia and a transient increase in on-target acute phase proteins. These effects were all considered to be clinically predictable, manageable, monitorable, and reversible.

PROBLEMS OF ISOLATION, IDENTIFICATION AND ANTIGENIC CHARACTERIZATION OF RECENT HUMAN A(H3N2) INFLUENZA VIRUSES

Human A (H3N2) influenza viruses are distinguished by a high rate of evolution and regularly cause epidemics around the world. Their ability to adapt and to escape from the host's immune response and to change their receptor specificity is very high. Over the past 20 years, these viruses have lost the ability to agglutinate red blood cells of chickens and turkeys and have practically ceased to propagate in chicken embryos - the main source of influenza vaccines. Isolation of viruses in the MDCK cell culture led to the selection of strains that lose one of the potential glycosylation sites. Many of the A (H3N2) strains have acquired mutations in neuraminidase, which distort the results of antigenic analysis in the hemagglutination inhibition test - the cornerstone method for the analysis of the match between viral isolates circulating in human population to strains selected for the influenza vaccines. In this regard, the characteristics of the antigenic properties of influenza A (H3N2) viruses by traditional methods become poorly informative, and the selection of vaccine strains of this subtype is erroneous, which is reflected in the discrepancy between vaccine and circulating A (H3N2) viruses in recent years (2013-2014, 2014 -2015, 2015-2016). The search, development and implementation of new algorithms for the isolation and antigen analysis of influenza A (H3N2) viruses are extremely urgent.

Pre-clinical and translational pharmacology of a human interleukin-22 IgG fusion protein for potential treatment of infectious or inflammatory diseases

Interleukin (IL)-22 plays protective roles in infections and in inflammatory diseases that have been linked to its meditation of innate immunity via multiple mechanisms. IL-22 binds specifically to its heterodimeric receptor, which is expressed on a variety of epithelial tissues. UTTR1147A is a recombinant fusion protein that links the human cytokine IL-22 with the Fc portion of human immunoglobulin (Ig) G4. Here, we report extensive in vitro and in vivo nonclinical studies that were conducted to characterize the pharmacological activity of UTTR1147A. The in vitro activity and potency of UTTR1147A were analyzed using primary human hepatocytes and human colonic epithelial cell lines. Assessment of in vivo efficacy was performed in a mouse colitis model and by measuring relevant pharmacodynamic biomarkers, including antimicrobial peptides REG3A/β, serum amyloid protein A (SAA) and lipopolysaccharide binding protein (LBP). The pharmacokinetic and pharmacodynamic characteristics of UTTR1147A were assessed in healthy mice, rats and cynomolgus monkeys. UTTR1147A induced STAT3 activation through binding to IL-22 receptor expressed in primary human hepatocytes and human colon cell lines. In both, activation occurred in a concentration-dependent manner with similar potencies. In the mouse colitis model, murine IL-22Fc- (muIL-22Fc) treated groups at doses of 1.25 μg and above had statistically lower average histologic colitis scores compared to the control treated group. Administration of muIL-22Fc or UTTR1147A was associated with a dose-dependent induction of PD markers REG3β and SAA in rodents as well as REG3A, SAA and LBP in cynomolgus monkeys. The combined data confirm pharmacological activity of IL-22Fc and support potential regenerative and protective mechanisms in epithelial tissues.

Anti-CD22 and anti-CD79b antibody-drug conjugates preferentially target proliferating B cells

BACKGROUND AND PURPOSE

CD22 and CD79b are cell-surface receptors expressed on B-cell-derived malignancies such as non-Hodgkin's lymphoma (NHL). An anti-mitotic agent, monomethyl auristatin E, was conjugated to anti-CD22 and anti-CD79b antibodies to develop target-specific therapies for NHL. The mechanism of action (MOA) and pharmacological and pharmacokinetic (PK) profiles of these antibody-drug conjugates (ADCs) were investigated in cynomolgus monkeys.

EXPERIMENTAL APPROACH

Animals were administered anti-CD22 or anti-CD79b ADCs, respective unconjugated antibodies or vehicle. Pharmacodynamic effects on total and proliferating B cells and serum PK were then assessed. Antibody-dependent cellular cytotoxicity (ADCC) and complement-dependent cytotoxicity (CDC) of the ADCs were evaluated in vitro.

KEY RESULTS

Depletion of B cells was observed after administration of either ADC or the respective unconjugated antibodies. An extended duration of depletion was observed in animals administered ADCs. Similarly, preferential depletion of proliferating B cells in blood and germinal centre B cells in spleen were only observed in animals administered ADCs. Serum PK profiles of ADCs and respective unconjugated antibodies were comparable. In vitro, anti-human CD22 and anti-human CD79b antibodies showed no or only moderate ADCC activity, respectively; neither antibody had CDC activity.

CONCLUSIONS AND IMPLICATIONS

The findings support the proposed MOA: initial depletion of total B cells by antibody-mediated opsonization, followed by preferential, sustained depletion of proliferating B cells by the auristatin conjugate due to its anti-mitotic action. Delivering potent anti-mitotic agents to B cells via the specificity of monoclonal antibodies provides a means to eliminate pathogenic B cells in NHL with improved risk-benefit profiles over traditional chemotherapeutics.

IL-22R Ligands IL-20, IL-22, and IL-24 Promote Wound Healing in Diabetic db/db Mice

Diabetic foot ulcers (DFU) are one of the major complications in type II diabetes patients and can result in amputation and morbidity. Although multiple approaches are used clinically to help wound closure, many patients still lack adequate treatment. Here we show that IL-20 subfamily cytokines are upregulated during normal wound healing. While there is a redundant role for each individual cytokine in this subfamily in wound healing, mice deficient in IL-22R, the common receptor chain for IL-20, IL-22, and IL-24, display a significant delay in wound healing. Furthermore, IL-20, IL-22 and IL-24 are all able to promote wound healing in type II diabetic db/db mice. Mechanistically, when compared to other growth factors such as VEGF and PDGF that accelerate wound healing in this model, IL-22 uniquely induced genes involved in reepithelialization, tissue remodeling and innate host defense mechanisms from wounded skin. Interestingly, IL-22 treatment showed superior efficacy compared to PDGF or VEGF in an infectious diabetic wound model. Taken together, our data suggest that IL-20 subfamily cytokines, particularly IL-20, IL-22, and IL-24, might provide therapeutic benefit for patients with DFU.

Preclinical Safety Profile of a Depleting Antibody against CRTh2 for Asthma: Well Tolerated Despite Unexpected CRTh2 Expression on Vascular Pericytes in the Central Nervous System and Gastric Mucosa

CRTh2 is expressed on immune cells that drive asthma pathophysiology. Current treatment options for severe asthma are inadequate and therapeutic antibody-mediated depletion of CRTh2-expressing cells represents a promising new therapeutic strategy. Here we report for the first time that CRTh2 is not only expressed on immune cells, but also on microvasculature in the central nervous system (CNS) and gastric mucosa in humans. Microvascular expression of CRTh2 raises a safety concern because a therapeutic antiCRTh2 antibody with enhanced depletion capacity could lead to vascular damage. To evaluate this safety risk, we characterized microvascular expression in human and in transgenic mice expressing human CRTh2 protein (hCRTh2.BAC.Tg) and found that CRTh2 is not localized to microvascular endothelium that is directly exposed to circulating therapeutic antibody, but rather, to pericytes that in the CNS are shielded from direct circulatory exposure by the blood-brain barrier. Immunohistochemical visualization of an intravenously administered antiCRTh2 antibody in transgenic mice revealed localization to microvascular pericytes in the gastric mucosa but not in the CNS, suggesting the blood-brain barrier effectively limits pericyte exposure to circulating therapeutic antibody in the CNS. Repeated dosing with a depleting antiCRTh2 antibody in hCRTh2.BAC.Tg mice revealed linear pharmacokinetics and no drug-related adverse findings in any tissues, including the CNS and gastric mucosa, despite complete depletion of CRTh2 expressing circulating eosinophils and basophils. Collectively, these studies demonstrate that the likelihood of drug-related CNS or gastrointestinal toxicity in humans treated with a therapeutic depleting antiCRTh2 antibody is low despite pericyte expression of CRTh2 in these tissues.

Nonselective inhibition of the epigenetic transcriptional regulator BET induces marked lymphoid and hematopoietic toxicity in mice

Bromo and extra terminal (BET) proteins (BRD2, BRD3, BRD4 and BRDT) are epigenetic transcriptional regulators required for efficient expression of growth promoting, cell cycle progression and antiapoptotic genes. Through their bromodomain, these proteins bind to acetylated lysine residues of histones and are recruited to transcriptionally active chromatin. Inhibition of the BET-histone interaction provides a tractable therapeutic strategy to treat diseases that may have epigenetic dysregulation. JQ1 is a small molecule that blocks BET interaction with histones. It has been shown to decrease proliferation of patient-derived multiple myeloma in vitro and to decrease tumor burden in vivo in xenograft mouse models. While targeting BET appears to be a viable and efficacious approach, the nonclinical safety profile of BET inhibition remains to be well-defined. We report that mice dosed with JQ1 at efficacious exposures demonstrate dose-dependent decreases in their lymphoid and immune cell compartments. At higher doses, JQ1 was not tolerated and due to induction of significant body weight loss led to early euthanasia. Flow cytometry analysis of lymphoid tissues showed a decrease in both B- and T-lymphocytes with a concomitant decrease in peripheral white blood cells that was confirmed by hematology. Further investigation with the inactive enantiomer of JQ1 showed that these in vivo effects were on-target mediated and not elicited through secondary pharmacology due to chemical structure.

An Overview of the Pathogenesis of Immune-mediated Skin Injury

The skin has a relatively limited range of responses to injury regardless of the specific mechanism underlying the insult. When the skin's barrier function is disrupted, it mounts an inflammatory and proliferative response in an effort to restore this essential function. The epidermal keratinocyte is central to the initiation of the skin's response, triggering an immunologic cascade that leads to the stereotypic morphologic responses that we encounter as pathologists. Drug-induced immune-mediated cutaneous injuries or "drug eruptions" are relatively common, sometimes with overlapping mechanisms, and it is often possible to classify these based on the classical hypersensitivity-type reactions. A specific type of immune-mediated skin injury is psoriasis. The pathogenesis of psoriasis is multifactorial but involves the interaction of environmental factors with a genetic predisposition. The initial stimulus triggering the development of psoriatic lesions involves activation of epidermal keratinocytes, with subsequent amplification driven by cross talk between the adaptive and innate immune systems. Several cytokines produced by Th17 T helper cells have recently been shown to be important in the pathogenesis of psoriasis, namely, interleukin-23 (IL-23) and IL-17, due to demonstrated clinical efficacy of cytokine blockade; and IL-22, based on its effects in both in vitro and in vivo models.

In Vitro Skin Models and Their Predictability in Defining Normal and Disease Biology, Pharmacology, and Toxicity

In vitro skin model systems are increasingly being used both in the early evaluation of therapeutic drug candidates and in confirmatory mechanistic studies. The most commonly used of these in vitro model systems are reconstituted human epidermis (RHE) models. These RHE models consist solely of epidermal keratinocytes, which comes with some limitations but also with the advantage of focusing toxicologic and pharmacologic evaluation on keratinocytes alone. RHE models can generally be implemented more quickly, easily, and reproducibly than in vivo models and can thus be used for high throughput compound screening while potentially reducing the need for animal studies. Histologic evaluation of RHE sections can be done quite easily, and the sections are very amenable to quantification via image analysis, including automated analysis. RHE model systems can provide very valuable early indications of therapeutic candidate biology, pharmacology, and toxicity; and early results have demonstrated that RHE models have been quite predictive for in vivo pharmacologic and toxicologic effects on the skin, including clinical skin toxicity.

[THE COMPARATIVE ANALYSIS OF EFFECTIVENESS OF QUICK TESTS IN DIAGNOSTIC OF INFLUENZA AND RESPIRATORY SYNCYTIAL VIRAL INFECTION IN CHILDREN]

The analysis was implemented concerning diagnostic parameters of commercial quick tests (immune chromatographic tests BinaxNOW Influenza A&B and BinaxNow RSV Alere, Scarborough Inc., USA) under detection of antigens of influenza virus A and respiratory syncytial virus in clinical materials. The polymerase chain reaction in real-time and isolation ofviruses in cell cultures. The analysis of naso-pharyngeal smears from 116 children demonstrated that sensitivity and specifcity of detection of influenza virus A using device mariPOC in comparison with polymerase chain reaction made up to 93.8% and 99.0% correspondingly at total concordance of results of both techniques as 98.3%. At diagnosing of respiratory syncytial virus using device mariPOC parameters made up to 77.3%, 98.9% and 862% as compared with polymerase chain reaction. The sensitivity, specificity and total concordance of results of immune chromatographic tests BinaxNOW in comparison ofpolymerase chain reaction made up to 86.7%, 100% and 96.2% correspondingly at detection of influenza virus A and 80.9%, 97.4% and 91.6% correspondingly at detection of respiratory syncytial virus. In comparison with isolation technique in cell cultures sensitivity of system mariPOC and immune chromatographic tests proved to be in 1.3-1.4 times higher at detection of influenza virus A and in 1.7-2 times higher in case of isolation of respiratory syncytial virus. There is no statistically significant differences between diagnostic parameters received for mariPOC and immune chromatographic tests at diagnosing influenza virus A and respiratory syncytial viral infection.

[IMPACT OF VARIOUS MULTIPLICITY OF INFECTION OF INFLUENZA A VIRUS ON PROLIFERATION AND APOPTOSIS INDUCTION IN CULTURED CELL LINES OF LYMPHOCYTIC AND MONOCYTIC ORIGIN (JURKAT, NC-37, THP-1 AND U-937)]

The severity of disease caused by influenza A infection depends not only on biological characteristics of the virus but also on the number of viral particles than penetrate the body. T- and B-lymphocytes as well as monocytes (macrophages) play a key role in the development of cell-based and humoral immunity as well as influenza virus elimination from the body. The present study describes the effect of influenza A virus infection on cell proliferation and induction of apoptosis in human cultured cell lines of T-, B-lymphocytic and monocytic origin infected with various multiplicity of infection (moi). Low moi of the virus stimulated cell proliferation; maximal effect has been registered 3-4 days after infection. But the fate of T-cells, B-cells and monocytes after initial infection was different: Jurkat cells continued intense proliferation while proliferation of NC-37, THP-1 and U-937 cells lowered. Prolonged (for 3 passages) cultivation of Jurkat, NC-37 and U-937 cell lines has shown that infection of these cell lines not only with low but also with medium and high moi also leads to stimulation of proliferation. Using a variety of methods for the detection of viral reproduction has clearly shown that infection of non-permissive human T-, B-cells and monocytes with influenza A virus leads to latent infection. So, low moi interferes with normal formation of viral particles, which in turn might stimulate cell proliferation and then be followed by induction of apoptosis. Antiviral drags rimantadine and ribavirin suppressed virus-induced cell proliferation; at the same time, induction of apoptosis was suppressed only by rimantadine and was enhanced by ribavirin. The data obtained provide strong support for the role of influenza A virus in the observed effects.

[Comparative study of MDCK and CaCo-2 cell lines for influenza virus isolation]

Study of effectiveness of CaCo-2 cell line for influenza virus isolation was carried out. It was shown that the properties of this cell line strongly depended on the source of its origin and cultivation conditions. The infectious activity of the influenza viruses on CaCo-2 cell line was virtually the same as in the MDCK cell line. The rate of the viral isolation was virtually identical for both cell lines tested, but viruses from post-mortem materials were isolated only in CaCo-2 cell line. In general, the CaCo-2 line is believed to be a valuable cell line for virological research, particularly for influenza virus isolation.

[Role of cellular cytoskeleton in influenza A infectious cycle]

Influenza remains a significant social threat especially regarding the emergence of new mutant or reassortant strains. Measures of prophylaxis do not provide complete and stable protection from infection and the use of antivirals results in high-level occurrence of resistant forms of viruses. Nowadays more and more attention is paid to find new targets for antiviral therapy that are not directly connected with virus proteins but can act indirectly through cellular mechanisms involved in viral replication. This approach requires complete understanding of various cellular pathways used by influenza virus. Here we present a brief overview of interactions between influenza A virus and the cell cytoskeleton. This interaction is initiated from the very beginning of influenza infection--adsorption--and continues with endocytosis, release of viral RNP and its entry into the nucleus. The role of cytoskeleton during the late stages of infection is also of great importance. It takes part in NP translocation from the nucleus to the cytoplasm, virus assembly and budding. The presence of cellular actin in certain influenza virions is therefore not accidental but reflects the peculiarities of interaction between a virus and a host cell.

[Development of influenza surveillance in Russia in the system of the WHO national influenza center]

Analysis of development influenza activity season 2010-2011 is presented. Significant participation of influenza A(H1N1)pdm09 virus and influenza B of Victoria lineage virus in the epidemic morbidity structure with minor participation ofA(H3N2) virus was revealed. The influenza viruses isolated in Russia according to antigenic properties were similar to the strains included in the vaccine composition. Drift variants of influenza A(H1N1)pdm09 viruses isolated in Astrakhan and St.-Petersburg were recognized using WHO CC in London as representatives of three new genetic groups.

[Evolutionary variability of influenza B viruses in Russian Federation in 2005-2012]

Specific traits of influenza B viruses circulation in Russia and worldwide in 2005-2012 were studied and the amount of influenza B viruses in the whole population of influenza viruses isolated in Russia was estimated. The trend toward antigenic drift for both Victoria and Yamagata lineages was characterized. The genetic analysis revealed amino acid changes that influenced the antigenic properties of the viruses. The match of the epidemic isolates and vaccine strains was corroborated.

Minipig as a potential translatable model for monoclonal antibody pharmacokinetics after intravenous and subcutaneous administration

Subcutaneous (SC) delivery is a common route of administration for therapeutic monoclonal antibodies (mAbs) with pharmacokinetic (PK)/pharmacodynamic (PD) properties requiring long-term or frequent drug administration. An ideal in vivo preclinical model for predicting human PK following SC administration may be one in which the skin and overall physiological characteristics are similar to that of humans. In this study, the PK properties of a series of therapeutic mAbs following intravenous (IV) and SC administration in Göttingen minipigs were compared with data obtained previously from humans. The present studies demonstrated: (1) minipig is predictive of human linear clearance; (2) the SC bioavailabilities in minipigs are weakly correlated with those in human; (3) minipig mAb SC absorption rates are generally higher than those in human and (4) the SC bioavailability appears to correlate with systemic clearance in minipigs. Given the important role of the neonatal Fc-receptor (FcRn) in the PK of mAbs, the in vitro binding affinities of these IgGs against porcine, human and cynomolgus monkey FcRn were tested. The result showed comparable FcRn binding affinities across species. Further, mAbs with higher isoelectric point tended to have faster systemic clearance and lower SC bioavailability in both minipig and human. Taken together, these data lend increased support for the use of the minipig as an alternative predictive model for human IV and SC PK of mAbs.

The yin and yang of immunomodulatory biologics: assessing the delicate balance between benefit and risk

A number of therapeutic immunomodulatory biologics, including antibodies, fusion proteins, and recombinant proteins, have been causally linked with serious adverse effects in humans. In nearly all cases, these serious adverse effects have been directly associated with the immunomodulatory biologic's intended pharmacologic activity or exaggerated pharmacology. Examples of immunomodulatory biologics known to cause serious adverse effects in the clinic ranging from immunostimulation and cytokine release syndrome (e.g., TGN1412) to immunosuppression with increased risk of opportunistic infections (e.g., TNF-α antagonists, anti-integrins) are presented. Specific examples of the nonclinical testing strategy used for the clinical risk assessment of these immunomodulatory biologics are discussed, with an emphasis on the clinical relevance and predictivity of the models. Infectious challenge animal models, in particular, were critically evaluated for their utility in evaluating clinical risk assessment versus understanding mechanism of action. The nonclinical safety testing strategy for an immunomodulatory biologic should be custom tailored to interrogate the biology of the immunologic target in order to best assess potential clinical risk. This nonclinical strategy should include mechanistic and efficacy models of pharmacologic activity and immunologic signaling pathways, in vitro immunologic assays such as cytokine release, and immunophenotypic assessment by flow cytometry, immunohistochemistry, and/or immunofluorescence, as appropriate.

[Comparative study of the differential susceptibility of different cell lines to pandemic H1N1v influenza viruses and avian influenza, swine influenza, and human influenza viruses]

The proliferation characteristics of influenza viruses of different origin were tested in various human and animal cell cultures. Pandemic H1N1v influenza and swine influenza viruses were shown to have a low infectious activity in virtually all the test lines. In spite of this, the replication of this group of viruses may be detected by de novo NP synthesis. These viruses are able to activate programmed cell death. Moreover, a low inoculative virus dose exerts a stimulating effect on cell proliferation in both suspension and monolayer cell lines.

A two-in-one antibody against HER3 and EGFR has superior inhibitory activity compared with monospecific antibodies

Extensive crosstalk among ErbB/HER receptors suggests that blocking signaling from more than one family member may be essential to effectively treat cancer and limit drug resistance. We generated a conventional IgG molecule MEHD7945A with dual HER3/EGFR specificity by phage display engineering and used structural and mutational studies to understand how a single antigen recognition surface binds two epitopes with high affinity. As a human IgG1, MEHD7945A exhibited dual action by inhibiting EGFR- and HER3-mediated signaling in vitro and in vivo and the ability to engage immune effector functions. Compared with monospecific anti-HER antibodies, MEHD7945A was more broadly efficacious in multiple tumor models, showing that combined inhibition of EGFR and HER3 with a single antibody is beneficial.

A humanized monoclonal antibody targeting the β7 integrin selectively blocks intestinal homing of T lymphocytes

BACKGROUND AND PURPOSE

rhuMAb Beta7 is a humanized anti-human β7 monoclonal antibody currently in phase I in inflammatory bowel disease. rhuMAb Beta7 binds the β7 subunit of the integrins α4β7 and αEβ7, blocking interaction with their ligands. These integrins play key roles in immune cell homing to and retention in mucosal sites, and are associated with chronic inflammatory diseases of the gastrointestinal tract. The goal of this study was to evaluate the mucosal specificity of rhuMAb Beta7.

EXPERIMENTAL APPROACH

We assessed the effect of murine anti-Beta7 on lymphocyte homing in mouse models of autoimmune disease. We also compared the effect of rhuMAb Beta7 on circulating mucosal-homing versus peripheral-homing T cells in naïve non-human primates.

KEY RESULTS

In cynomolgus monkeys, occupancy of β7 integrin receptors by rhuMAb Beta7 correlated with an increase in circulating β7(+) mucosal-homing lymphocytes, with no apparent effect on levels of circulating β7(-) peripheral-homing lymphocytes. rhuMAb Beta7 also inhibited lymphocyte homing to the inflamed colons of severe combined immunodeficient mice in CD45RB(high) CD4(+) T-cell transfer models. Consistent with a lack of effect on peripheral homing, in a mouse model of experimental autoimmune encephalomyelitis, anti-β7 treatment resulted in no amelioration of CNS inflammation.

CONCLUSIONS AND IMPLICATIONS

The results presented here suggest that rhuMAb Beta7 selectively blocks lymphocyte homing to the gastrointestinal tract without affecting lymphocyte trafficking to non-mucosal tissues. rhuMAb Beta7 provides a targeted therapeutic approach with the potential for a more attractive benefit:risk ratio than currently available inflammatory bowel disease therapies.

[Analysis of pandemic influenza in Russia as a part of the global process based on data of an influenza monitoring reference center]

AIM

Characterization of features of influenza pandemic development in Russia in relation to global process.

MATERIALS AND METHODS

Pandemic monitoring was performed by using results of integrative analysis of laboratory diagnostic and population morbidity data from 49 supporting bases of Federal center of influenza from various cities in Russian Federation. Isolation of influenza virus was carried out in MDCK cells and chicken embryos under BSL-3 conditions. Reference virus A/California/07/09 obtained from CDC (Atlanta, USA) and antisera against this strain contained in WHO kit were used for antigenic analysis; rat antisera, new monoclonal antibodies against pandemic influenza virus developed by Research institute of influenza were also used.

RESULTS

Based on PCR monitoring during epidemic peak, rate of pandemic influenza identification reached 45-49% of examined patients. About 53% of lethal cases of respiratory infections were caused by pandemic influenza virus, while predominately young people died from pneumonia and acute respiratory distress syndrome. Russian isolates generally were antigenically and genetically similar to the parent pandemic strain--influenza virusA/California/07/09, but contained S203T substitution in hemagglutinin. A number of strains contained D222G mutation that is responsible for the expansion of substrate specificity, as well as strain specific substitutions in hemagglutinin and neuraminidase molecules. The investigated isolates were resistant to remantadin, but sensitive to oseltamivir.

CONCLUSION

Due to the formation of population immunity after the end of the first pandemic wave new drift variants of the virus capable of overcoming this formed immunity should be expected that apparently will require the correction of vaccine composition for the 2011 - 2012 season.

[Pandemic influenza 2009 in Russia. Characteristics of the isolation and biological properties of viruses]

Research Institute of Influenza, Ministry of Health and Social Development of Russia, Saint Petersburg The characteristics of the isolation of pandemic influenza A(H1N1)v viruses were studied on chick embryos (CE) and MDCK cell culture. The materials (nasal swabs and autopsies) were collected in different regions Russia in the period from 20 July to 30 December 2009. The paper gives the data of the antigenic analysis of isolates, their capacity to multiply in different species-specific and tissue cell cultures. The viruses isolated on CE were shown to have higher hemagglutination titers and to be more stable. Isolation from the autopsies was effective only on CE. All the test cell lines other than MDCK were insensitive to the isolated pandemic influenza strains. The antigenic analysis showed no significant antigenic drift of the viruses isolated during the first wave of the pandemic in the Russian Federation.

[The 2009 pandemic influenza in Russia. I. Diagnosis and molecular biological characteristics of the virus]

The analysis of 1558 clinical samples revealed influenza virus A(H1N1v) RNA in 339 patients with influenza and 163 fatal cases,which was made in May to December 2009. Data on the antigenic properties of more than 250 of pandemic virus strains isolated at the Research Institute of Influenza and the molecular genetic characteristics of 31 strains are presented. All the test isolates were found to have the S203 substitution in hemagglutinin, which was characteristic of one of 5 minor genome A(H1N1v) virus variants found in the United States and Mexico in 2009. All the test strains contain the S31N substitution in the M2 protein, which determines viral resistance to adamantine, and have no H275Y substitution in neuraminidase, which determines oseltamivir resistance. The substitution of amino acid residue of Asp to Gly at position 222 of HA was found in 8 (73%) of 11 isolates from postmortem lung and trachea samples and in 2 (10%) of 20 isolates from nasopharyngeal swabs. The determination of the pathogenic role of this substitution calls for further investigations.

[Influence of rimantadine, ribavirine and triazavirine on influenza A virus replication in human monolayer and lymphoblastoid cell lines]

The influence of antivirals, such as rimantadine, ribavirine and triazavirine on influenza virus replication in human cell cultures was evaluated. All the antivirals inhibited viral nucleoprotein NP synthesis. The strongest effect was shown for ribavirine in lung carcinoma A-549 cells and endothelial ECV-304 cells. Hoechst-33258 staining revealed induction of apoptosis in all the cell lines. Rimantadine and ribavirine inhibited virus-induced apoptosis while ribavirine enhanced it. The effect was registered in monolayer cell cultures as well as in suspension cell cultures. The influence of the antiviral drugs on the virus-induced cell proliferation in the suspension cell cultures is also described.

IL-27 supports germinal center function by enhancing IL-21 production and the function of T follicular helper cells

IL-27 signaling directly into T cells is needed for follicular T helper cell survival, germinal center formation, and the production of T cell–dependent high-affinity antibodies in mice.

Maturation and selection of high-affinity B cell clones in the germinal center (GC) relies on support from T follicular helper (T_FH) cells. T_FH cells are characterized by their localization to the B cell follicle and their high expression of the costimulatory molecules ICOS and PD1 and the cytokine IL-21, which promotes immunoglobulin (Ig) class switching and production by B cells. We show that the heterodimeric cytokine IL-27 is critical for the function of T_FH cells and for normal and pathogenic GC responses. IL-27 signaling to T cells results in the production of IL-21, a known autocrine factor for the maintenance of T_FH cells, in a STAT3-dependent manner. IL-27 also enhances the survival of activated CD4⁺ T cells and the expression of T_FH cell phenotypic markers. In vivo, expression of the IL-27Rα chain is required to support IL-21 production and T_FH cell survival in a T cell–intrinsic manner. The production of high-affinity antibodies is reduced, and pristane-elicited autoantibodies and glomerulonephritis are significantly diminished, in Il27ra^−/− mice. Together, our data show a nonredundant role for IL-27 in the development of T cell–dependent antibody responses.

Actin-bundling protein L-plastin regulates T cell activation

Engagement of TCRs induces actin rearrangements, which are critical for T cell activation. T cell responses require new actin polymerization, but the significance of higher-order actin structures, such as microfilament bundles, is unknown. To determine the role of the actin-bundling protein leukocyte-plastin (L-plastin; LPL) in this process, T cells from LPL(-/-) mice were studied. LPL(-/-) T cells were markedly defective in TCR-mediated cytokine production and proliferation. LPL(-/-) T cells also spread inefficiently on surfaces with immobilized TCR ligands and formed smaller immunological synapses with APCs, likely due to defective formation of lamellipodia. LPL(-/-) mice showed delayed rejection of skin allografts after release from immunosuppression. Moreover, LPL(-/-) mice developed much less severe neurologic symptoms in experimental autoimmune encephalomyelitis, which correlated with impaired T cell responses to Ag, manifested by reduced proliferation and production of IFN-γ and IL-17. Thus, LPL-dependent actin bundling facilitates the formation of lamellipodia and normal immunological synapses and thereby enables T cell activation.

B-cell activation influences T-cell polarization and outcome of anti-CD20 B-cell depletion in central nervous system autoimmunity

OBJECTIVE

Clinical studies indicate that anti-CD20 B-cell depletion may be an effective multiple sclerosis (MS) therapy. We investigated mechanisms of anti-CD20-mediated immune modulation using 2 paradigms of experimental autoimmune encephalomyelitis (EAE).

METHODS

Murine EAE was induced by recombinant myelin oligodendrocyte glycoprotein (rMOG), a model in which B cells are considered to contribute pathogenically, or MOG peptide (p)35-55, which does not require B cells.

RESULTS

In EAE induced by rMOG, B cells became activated and, when serving as antigen-presenting cells (APCs), promoted differentiation of proinflammatory MOG-specific Th1 and Th17 cells. B-cell depletion prevented or reversed established rMOG-induced EAE, which was associated with less central nervous system (CNS) inflammation, elimination of meningeal B cells, and reduction of MOG-specific Th1 and Th17 cells. In contrast, in MOG p35-55-induced EAE, B cells did not become activated or efficiently polarize proinflammatory MOG-specific T cells, similar to naive B cells. In this setting, anti-CD20 treatment exacerbated EAE, and did not impede development of Th1 or Th17 cells. Irrespective of the EAE model used, B-cell depletion reduced the frequency of CD4(+)CD25(+)Foxp3(+) regulatory T cells (Treg), and increased the proinflammatory polarizing capacity of remaining myeloid APCs.

INTERPRETATION

Our study highlights distinct roles for B cells in CNS autoimmunity. Clinical benefit from anti-CD20 treatment may relate to inhibition of proinflammatory B cell APC function. In certain clinical settings, however, elimination of unactivated B cells, which participate in regulation of T cells and other APC, may be undesirable. Differences in immune responses to MOG protein and peptide may be important considerations when choosing an EAE model for testing novel B cell-targeting agents for MS.

[Etiological characteristics of the influenza epidemics of 2006-2009 in the Russian Federation (according to the data of the Research Institute of Influenza, North-Western Branch, Russian Academy of Medical Sciences)]

The basic trends in the evolution of influenza A and B in the Russian Federation during the epidemic seasons of 2006-2009 were studied on the basis of an antigenic analysis of 1774 Influenza isolated at the Research Institute of Influenza (RII), North-Western Branch, Russian Academy of Medical Sciences, and sent from resting bases (the regional centers of the Russian Inspectorate for the Protection of Consumer Rights and Human Welfare, which collaborate with the RII). Although the trends in the substitution of representative strains generally coincide with the world patterns, the authors revealed some specific features of the antigenic drift of influenza viruses in the Russian Federation and regional varieties. Data on some biological properties and those of the antigenic analysis of the first pandemic influenza A(H1NI)v strains isolated at the RII from Saint Petersburg patients in July-August 2009 are also given in the paper.

[Study of the antiviral activity of Russian anti-influenza agents in cell culture and animal models]

The study of the antiviral activity of Russian anti-influenza agents in the cultured MDCK cells demonstrated that arbidol and ribavirin inhibited the reproduction of various influenza A virus strains, including rimantadine- and ozeltamivir-resistant variants, as well as influenza B viruses (IC50 2-8.5 microg/ml). Rimantadine at concentrations of 1-5 microg/ml completely inhibited the reproduction of reference and ozeltamivir-resistant influenza A virus strains, and it had no effect on the reproduction of influenza B viruses and rimantadine-resistant influenza A viruses. Arbidol and ribavirin also inhibited the reproduction of pandemic influenza A/California/04/2009(H1N1), A/California/07/2009(H1N1), and A/Moscow/01/2009(H1N1)swl viruses in the cultured MDCK cells (IC50 = 1.5-4.0 microg/ml) while rimantadine had no effect on their reproduction. The cultured cells showed no significant antiviral activity of ingavirin at nontoxic concentrations (up to 200 microg/ml) against all study strains of influenza A and B viruses, including pandemic A(H1N1) influenza virus strains. The activity of rimantadine, arbidol, and ingavirin was found on a model of Influenza pneumonia in mice infected with their adopted influenza A/Aichi/2/69(H3N2) virus. The preventive efficacy of the three test agents was similar and most pronounced when they were used 96 hours before infection, by preventing 40-50% death in the animals and their body weight loss and by increasing their survival by 1.3-1.5 times. Arbidol and rimantadine were more effective when used for treatment and prophylaxis in doses of 30 and 10 mg/kg/day, respectively, by protecting the infected animals from 60-80% death, increasing their survival by 1.7-2 times, and preventing their body weight loss as compared with the control. The same experiments with ingavirin showed that this agent was less effective than arbidol and rimantadine. Thus, arbidol and rimantadine have a pronounced antiviral infection in both cell culture and a model of influenza pneumonia. The found efficacy of ingavirin on an integral model of murine influenza pneumonia without its activity in the cultured cells is likely to be due to other pharmacological properties of the drug rather than its direct virus-specific action.

The serine protease marapsin is expressed in stratified squamous epithelia and is up-regulated in the hyperproliferative epidermis of psoriasis and regenerating wounds

The trypsin-like serine protease marapsin is a member of the large protease gene cluster at human chromosome 16p13.3, which also contains the structurally related proteases testisin, tryptase epsilon, tryptase gamma, and EOS. To gain insight into the biological functions of marapsin, we undertook a detailed gene expression analysis. It showed that marapsin expression was restricted to tissues containing stratified squamous epithelia and was absent or only weakly expressed in all other tissues, including the pancreas. Marapsin was constitutively expressed in nonkeratinizing stratified squamous epithelia of human esophagus, tonsil, cervix, larynx, and cornea. In the keratinizing stratified squamous epidermis of skin, however, its expression was induced only during epidermal hyperproliferation, such as in psoriasis and in murine wound healing. In fact, marapsin was the second most strongly up-regulated protease in psoriatic lesions, where expression was localized to the upper region of the hyperplastic epidermis. Similarly, in the hyperproliferative epithelium of regenerating murine skin wounds, marapsin localized to the suprabasal layers, where keratinocytes undergo squamous differentiation. The transient up-regulation of marapsin, which closely correlated with re-epithelialization, was virtually absent in a genetic mouse model of delayed wound closure. These results suggested a function during the process of re-epithelialization. Furthermore, in reconstituted human epidermis, a model system of epidermal differentiation, members of the IL-20 subfamily of cytokines, such as IL-22, induced marapsin expression. Consistent with a physiologic role in marapsin regulation, IL-22 was also strongly expressed in re-epithelializing skin wounds. Marapsin's restricted expression, localization, and cytokine-inducible expression suggest a role in the terminal differentiation of keratinocytes in hyperproliferating squamous epithelia.

Evidence for an asialoglycoprotein receptor on nonparenchymal cells for O-linked glycoproteins

B cell-activating factor receptor 3 (BR3)-Fc is an IgG1-receptor dimeric fusion protein that has multiple O-linked glycosylation sites and sialylation levels that can vary in the manufacturing process. Increased sialic acid levels resulted from increased site occupancy with the O-linked N-acetylgalactosamine (GalNAc-Gal), but because the ratio of sialic acid per mole of oligosaccharide remained approximately 1, this led to increased asialo terminal GalNAc. Previous studies have demonstrated an effect of terminal asialo Gal or GalNAc on the clearance of glycoproteins due to uptake and degradation by lectin receptors in the liver. However, the previous studies examined N-linked oligosaccharides, and there are less data regarding O-linked oligosaccharides. The objective of these studies was to determine the effects on the pharmacokinetics and distribution of the asialo terminal GalNAc and varying amounts of sialic acid residues on BR3-Fc. The results of the data presented here suggest that exposed Gal on the desialylated BR3-Fc led to rapid clearance due to uptake and degradation in the liver that was associated with nonparenchymal cells. It is interesting to note that the data indicated a decreased clearance and increased exposure of BR3-Fc as the sialic acid levels increased, even though increased sialic acid was associated with increased asialo GalNAc. Therefore, the exposed GalNAc did not seem to play a role in the clearance of BR3-Fc; although the Gal linked to the hydroxyl group at position 3 may have prevented an interaction. Because we did not see uptake of desialylated BR3-Fc in hepatocytes where the asialoglycoprotein receptor is localized, this nonparenchymal cell lectin may have preference for O-linked glycoproteins.

Interleukin-22 mediates early host defense against attaching and effacing bacterial pathogens

Infections by attaching and effacing (A/E) bacterial pathogens, such as Escherichia coli O157:H7, pose a serious threat to public health. Using a mouse A/E pathogen, Citrobacter rodentium, we show that interleukin-22 (IL-22) has a crucial role in the early phase of host defense against C. rodentium. Infection of IL-22 knockout mice results in increased intestinal epithelial damage, systemic bacterial burden and mortality. We also find that IL-23 is required for the early induction of IL-22 during C. rodentium infection, and adaptive immunity is not essential for the protective role of IL-22 in this model. Instead, IL-22 is required for the direct induction of the Reg family of antimicrobial proteins, including RegIIIbeta and RegIIIgamma, in colonic epithelial cells. Exogenous mouse or human RegIIIgamma substantially improves survival of IL-22 knockout mice after C. rodentium infection. Together, our data identify a new innate immune function for IL-22 in regulating early defense mechanisms against A/E bacterial pathogens.

The effects of IL-20 subfamily cytokines on reconstituted human epidermis suggest potential roles in cutaneous innate defense and pathogenic adaptive immunity in psoriasis

IL-19, IL-20, IL-22, IL-24, and IL-26 are members of the IL-10 family of cytokines that have been shown to be up-regulated in psoriatic skin. Contrary to IL-10, these cytokines signal using receptor complex R1 subunits that are preferentially expressed on cells of epithelial origin; thus, we henceforth refer to them as the IL-20 subfamily cytokines. In this study, we show that primary human keratinocytes (KCs) express receptors for these cytokines and that IL-19, IL-20, IL-22, and IL-24 induce acanthosis in reconstituted human epidermis (RHE) in a dose-dependent manner. These cytokines also induce expression of the psoriasis-associated protein S100A7 and keratin 16 in RHE and cause persistent activation of Stat3 with nuclear localization. IL-22 had the most pronounced effects on KC proliferation and on the differentiation of KCs in RHE, inducing a decrease in the granular cell layer (hypogranulosis). Furthermore, gene expression analysis performed on cultured RHE treated with these cytokines showed that IL-19, IL-20, IL-22, and IL-24 regulate many of these same genes to variable degrees, inducing a gene expression profile consistent with inflammatory responses, wound healing re-epithelialization, and altered differentiation. Many of these genes have also been found to be up-regulated in psoriatic skin, including several chemokines, beta-defensins, S100 family proteins, and kallikreins. These results confirm that IL-20 subfamily cytokines are important regulators of epidermal KC biology with potentially pivotal roles in the immunopathology of psoriasis.

Interleukin-22, a T(H)17 cytokine, mediates IL-23-induced dermal inflammation and acanthosis

Psoriasis is a chronic inflammatory skin disease characterized by hyperplasia of the epidermis (acanthosis), infiltration of leukocytes into both the dermis and epidermis, and dilation and growth of blood vessels. The underlying cause of the epidermal acanthosis in psoriasis is still largely unknown. Recently, interleukin (IL)-23, a cytokine involved in the development of IL-17-producing T helper cells (T(H)17 cells), was found to have a potential function in the pathogenesis of psoriasis. Here we show that IL-22 is preferentially produced by T(H)17 cells and mediates the acanthosis induced by IL-23. We found that IL-23 or IL-6 can directly induce the production of IL-22 from both murine and human naive T cells. However, the production of IL-22 and IL-17 from T(H)17 cells is differentially regulated. Transforming growth factor-beta, although crucial for IL-17 production, actually inhibits IL-22 production. Furthermore, IL-22 mediates IL-23-induced acanthosis and dermal inflammation through the activation of Stat3 (signal transduction and activators of transcription 3) in vivo. Our results suggest that T(H)17 cells, through the production of both IL-22 and IL-17, might have essential functions in host defence and in the pathogenesis of autoimmune diseases such as psoriasis. IL-22, as an effector cytokine produced by T cells, mediates the crosstalk between the immune system and epithelial cells.

Requirement for coronin 1 in T lymphocyte trafficking and cellular homeostasis

The evolutionarily conserved actin-related protein (Arp2/3) complex is a key component of actin filament networks that is dynamically regulated by nucleation-promoting and inhibitory factors. Although much is known about actin assembly, the physiologic functions of inhibitory proteins are unclear. We generated coronin 1-/- mice and found that coronin 1 exerted an inhibitory effect on cellular steady-state F-actin formation via an Arp2/3-dependent mechanism. Whereas coronin 1 was required for chemokine-mediated migration, it was dispensable for T cell antigen receptor functions in T cells. Moreover, actin dynamics, through a mitochondrial pathway, was linked to lymphocyte homeostasis.

Interleukin 27 limits autoimmune encephalomyelitis by suppressing the development of interleukin 17-producing T cells

Interleukin 27 (IL-27) was first characterized as a proinflammatory cytokine with T helper type 1-inducing activity. However, subsequent work has demonstrated that mice deficient in IL-27 receptor (IL-27R alpha) show exacerbated inflammatory responses to a variety of challenges, suggesting that IL-27 has important immunoregulatory functions in vivo. Here we demonstrate that IL-27R alpha-deficient mice were hypersusceptible to experimental autoimmune encephalomyelitis and generated more IL-17-producing T helper cells. IL-27 acted directly on effector T cells to suppress the development of IL-17-producing T helper cells mediated by IL-6 and transforming growth factor-beta. This suppressive activity was dependent on the transcription factor STAT1 and was independent of interferon-gamma. Finally, IL-27 suppressed IL-6-mediated T cell proliferation. These data provide a mechanistic explanation for the IL-27-mediated immune suppression noted in several in vivo models of inflammation.

Pharmacokinetics, pharmacodynamics, and safety assessment of palifermin (rHuKGF) in healthy volunteers

BACKGROUND

Palifermin is a recombinant human keratinocyte growth factor approved to decrease the incidence and duration of severe oral mucositis in patients with hematologic malignancies who received myelotoxic therapy requiring hematopoietic stem cell support.

METHODS

This randomized, double-blind, placebo-controlled study investigated the pharmacokinetics, pharmacodynamics, and safety of palifermin in healthy volunteers after single, escalating doses (60 to 250 mug/kg). Pharmacodynamic measurements (Ki67 staining) assessing buccal mucosal epithelial proliferation were performed at baseline and at 48 or 72 hours after dosing.

RESULTS

Exposure to palifermin increased approximately dose proportionally, with a 3-fold increase observed for a 4-fold increase in dose. Palifermin concentrations decreased sharply during the first 0.5 to 1.5 hours after dosing, slightly increased or plateaued between 1.5 and 6 hours, and subsequently decreased. The overall mean systemic clearance and volume of distribution at steady state were 590 mL/h/kg and 2000 mL/kg, respectively. The mean half-life ranged from 4.5 to 6 hours across the dose levels. The mean and SD ratio of Ki67 staining at 48 hours after dosing to baseline was 1.19 (0.24) for placebo, 2.02 (0.60) for 60 mug/kg, 3.04 (1.13) for 120 mug/kg, and 4.66 (0.77) for 250 mug/kg-treated groups.

CONCLUSION

Palifermin exhibited linear pharmacokinetics and caused dose-dependent epithelial proliferation.

A soluble BAFF antagonist, BR3-Fc, decreases peripheral blood B cells and lymphoid tissue marginal zone and follicular B cells in cynomolgus monkeys

BAFF (also known as BLyS), a member of the tumor necrosis factor superfamily, plays a critical role in the maturation and development of B cells. BAFF has three receptors on B cells, the most crucial of which is BR3. In this study, we demonstrate the biological outcome of BAFF blockade in cynomolgus monkeys using a soluble fusion protein consisting of human BR3 and human IgG1 Fc. In vitro, BR3-Fc blocked BAFF-mediated survival and proliferation of cynomolgus monkey B cells. Weekly treatment of cynomolgus monkeys with BR3-Fc for 13 to 18 weeks resulted in significant B-cell reduction in the peripheral blood and in lymphoid organs. CD21(high) B cells in lymphoid tissues, a subset analogous to human marginal zone B cells, expressed nearly twofold higher BR3 levels than did CD21(med) B cells. Lymphoid tissue flow cytometric analysis showed that BR3-Fc reduced this CD21(high) B-cell subset to a greater extent than it reduced CD21(med) B cells. Dual-label immunohistochemistry and morphometric image analysis supported these results by demonstrating that BR3-Fc reduced a significant proportion of the B cells within the splenic inner and outer marginal zones. These findings should prove very useful in guiding the desired therapeutic use of BR3-Fc for autoimmune diseases in the clinic.

Effect of recombinant human keratinocyte growth factor (rHuKGF) on the immunopathogenesis of intestinal graft-vs.-host disease induced without a preconditioning regimen

We studied the effect of rHuKGF on acute, lethal graft- vs.-host disease (GVHD) in the C57BL/6-->(C57BL/6 X DBA/2)F(1)-hybrid model. rHuKGF-treated recipients did not develop intestinal GVHD despite elevated levels of intestinal NO and TNF alpha, did not develop endotoxemia, and did not die. LPS augmented serum TNF alpha release and intestinal NO production, but did not induce intestinal epithelial cell apoptosis, a phenomenon associated with acute GVHD. These data suggest that KGF prevents the development of acute lethal GVHD by protecting epithelial cell injury mediated by TNF-alpha, NO, and other potential cytotoxic factors. We noted a moderate reduction in intestinal KGFR mRNA expression in untreated GVH mice on day 8, when IFN-gamma mRNA levels were highest. This reduction in KGFR mRNA levels was not seen in recipients of IFN-gamma gene knockout grafts, suggesting that IFN-gamma may be involved in reducing KGFR mRNA expression in the intestine. A similar reduction in intestinal KGFR mRNA expression was also seen in rHuKGF-treated recipients, suggesting that rHuKGF does not mediate its protective effect by maintaining KGFR at control levels. KGF-treatment also redirected the cytokine response in acute GVH mice from Th1 to a mixed pattern of both Th1 and Th2 cytokines. This was associated with histopathologic changes resembling chronic GVHD.

CD4+CD45RBHi T cell transfer induced colitis in mice is accompanied by osteopenia which is treatable with recombinant human osteoprotegerin

BACKGROUND AND AIMS

Transfer of CD4+CD45RBHi T cells into semi syngeneic immunodeficient mice represents a model of inflammatory bowel disease (IBD). As patients with IBD often suffer from osteopenia, we studied if this T cell transfer in mice results in osteopenia in addition to colitis, and if treatment with osteoprotegerin (OPG) has effects on the bone mineral density of T cell transferred mice. We also investigated whether osteopenia was due to malabsorption as a result of a dysregulated digestive tract or as a consequence of the inflammatory process.

METHODS

CD4+CD45RBHi or CD4+CD45RBLo T cells (4 x 10(5)) were sorted from CB6F1 and transferred into C.B.17 scid/scid mice. Recipient mice were treated with human IgG1 Fc (control) or Fc-OPG three times per week in a prophylactic regimen as well as a therapeutic regimen (after 10% body weight loss) and were evaluated for osteopenia and colitis.

RESULTS

Mice that received CD4+CD45RBHi T cells developed osteopenia (as indicated by decreased bone density accompanied by decreased osteoblasts and increased osteoclasts) and colitis (as indicated by histological changes in the large intestine). Mice that received CD4+CD45RBLo T cells developed neither osteopenia nor colitis. All animals consumed, on average, the same amount of food and water over the course of the study. Prophylactic treatment with Fc-OPG increased bone density in mice that received either CD4+CD45RBHi or CD4+CD45RBLo T cells but had no effects on the gastrointestinal tract. Fc-OPG treatment of osteopenic mice with established IBD caused the normalisation of bone density. Osteopenia in CD4+CD45RBHi T cell recipients was accompanied by hypoparathyroidism that was partially normalised by treatment with Fc-OPG. CD4+CD45RBHi T cell recipients also had a bone marrow inflammatory cell infiltrate expressing tumour necrosis factor alpha which was unaffected by treatment with Fc-OPG.

CONCLUSIONS

CD4+CD45RBHi T cell transfer results in osteopenia in addition to colitis. Evidence suggests that this osteopenia was induced by inflammatory cell infiltration and not by malabsorption of calcium. Recombinant human osteoprotegerin effectively treated the osteopenia. OPG may be a useful therapeutic option for treating osteopenia in patients with IBD.

The role of interferon-gamma, nitric oxide and lipopolysaccharide in intestinal graft-versus-host disease developing in F1-hybrid mice

(C57BL/6 x DBA/2)F1-hybrid mice injected with lymphoid cells from wild-type, C57BL/6 donors develop acute, lethal graft-versus-host disease (GVHD) in which the intestine is a major target. In its destructive phase intestinal GVHD is characterized by apoptosis of intestinal crypt epithelial cells and the development of endotoxaemia. Injection of as little as 10 microg endotoxin is lethal in mice with acute GVHD, and associated with the release of large amounts of tumour necrosis factor-alpha (TNF-alpha) into the serum. To explore the role of interferon-gamma (IFN-gamma) in the pathogenesis of intestinal GVHD we used IFN-gamma gene knockout (gko) mice as donors. Recipients of grafts from these donors did not develop intestinal GVHD and, unlike recipients of wild-type grafts, did not die when injected with lipopolysaccharide (LPS). We also found that injection 10 microg LPS into recipients of wild-type grafts induced apoptosis of intestinal epithelial crypt cells and was associated with a burst of nitric oxide production in the intestine. Administration of N(omega)nitro L-arginine methyl ester blocked this response. In contrast, LPS did not induce either intestinal epithelial cell apoptosis or increased nitric oxide production in recipients of IFN-gamma gko grafts. These findings indicate that donor-derived IFN-gamma is instrumental for the development of intestinal GVHD. In a previous study we showed that recipients of IFN-gamma gko grafts develop high levels of LPS-induced TNF-alpha release. When our current data are viewed in the context of this observation, they suggest that intestinal epithelial cell apoptosis in the parent-->F1-hybrid model of acute GVHD is mediated primarily by nitric oxide rather than TNF-alpha, and that this depends on donor-derived IFN-gamma.

Transgenic overexpression of human IL-17E results in eosinophilia, B-lymphocyte hyperplasia, and altered antibody production

We have identified and cloned a novel human cytokine with homology to cytokines of the interleukin-17 (IL-17) family, which we have termed human IL-17E (hIL-17E). With the identification of several IL-17 family members, it is critical to understand the in vivo function of these molecules. We have generated transgenic mice overexpressing hIL-17E using an apolipoprotein E (ApoE) hepatic promoter. These mice displayed changes in the peripheral blood, particularly, a 3-fold increase in total leukocytes consisting of increases in eosinophils, lymphocytes, and neutrophils. Splenomegaly and lymphoadenopathy were predominant and included marked eosinophil infiltrates and lymphoid hyperplasia. CCR3(+) eosinophils increased in the blood and lymph nodes of the transgenic mice by 50- and 300-fold, respectively. Eosinophils also increased 8- to 18-fold in the bone marrow and spleen, respectively. In the bone marrow, most of the eosinophils had an immature appearance. CD19(+) B cells increased 2- to 5-fold in the peripheral blood, 2-fold in the spleen, and 10-fold in the lymph nodes of transgenic mice, whereas CD4(+) T lymphocytes increased 2-fold in both blood and spleen. High serum levels of the cytokines IL-2, IL-4, IL-5, granulocyte colony-stimulating factor, eotaxin, and interferon gamma were observed. Consistent with B-lymphocyte increases, serum immunoglobulin (Ig) M, IgG, and IgE were significantly elevated. Antigenic challenge of the transgenic mice with keyhole limpet hemocyanin (KLH) resulted in a decrease in anti-KLH IgG accompanied by increases of anti-KLH IgA and IgE. In situ hybridization of transgenic tissues revealed that IL-17Rh1 (IL-17BR/Evi27), a receptor that binds IL-17E, is up-regulated. Taken together, these data indicate that IL-17E regulates hematopoietic and immune functions, stimulating the development of eosinophils and B lymphocytes. The fact that hIL-17E overexpression results in high levels of circulating eosinophils, IL-4, IL-5, eotaxin, and IgE suggests that IL-17E may be a proinflammatory cytokine favoring Th2-type immune responses.