Discovery and Preclinical Activity of BMS-986351, an Antibody to SIRPα That Enhances Macrophage-mediated Tumor Phagocytosis When Combined with Opsonizing Antibodies

In normal cells, binding of the transmembrane protein CD47 to signal regulatory protein-α (SIRPα) on macrophages induces an antiphagocytic signal. Tumor cells hijack this pathway and overexpress CD47 to evade immune destruction. Macrophage antitumor activity can be restored by simultaneously blocking the CD47-SIRPα signaling axis and inducing a prophagocytic signal via tumor-opsonizing antibodies. We identified a novel, fully human mAb (BMS-986351) that binds SIRPα with high affinity. BMS-986351 demonstrated broad binding coverage across SIRPα polymorphisms and potently blocked CD47-SIRPα binding at the CD47 binding site in a dose-dependent manner. In vitro, BMS-986351 increased phagocytic activity against cell lines from solid tumors and hematologic malignancies, and this effect was markedly enhanced when BMS-986351 was combined with the opsonizing antibodies cetuximab and rituximab. A phase I dose-escalation/-expansion study of BMS-986351 for the treatment of advanced solid and hematologic malignancies is underway (NCT03783403).

SIGNIFICANCE

Increasing the phagocytotic capabilities of tumor-associated macrophages by modulating macrophage-tumor cell surface signaling via the CD47-SIRPα axis is a novel strategy. Molecules targeting CD47 have potential but its ubiquitous expression necessitates higher therapeutic doses to overcome potential antigen sink effects. The restricted expression pattern of SIRPα may limit toxicities and lower doses of the SIRPα antibody BMS-986351 may overcome target mediated drug disposition while maintaining the desired pharmacology.

CC-96673 (BMS-986358), an affinity-tuned anti-CD47 and CD20 bispecific antibody with fully functional fc, selectively targets and depletes non-Hodgkin's lymphoma

Cluster of differentiation 47 (CD47) is a transmembrane protein highly expressed in tumor cells that interacts with signal regulatory protein alpha (SIRPα) and triggers a "don't eat me" signal to the macrophage, inhibiting phagocytosis and enabling tumor escape from immunosurveillance. The CD47-SIRPα axis has become an important target for cancer immunotherapy. To date, the advancement of CD47-targeted modalities is hindered by the ubiquitous expression of the target, often leading to rapid drug elimination and hematologic toxicity including anemia. To overcome those challenges a bispecific approach was taken. CC-96673, a humanized IgG1 bispecific antibody co-targeting CD47 and CD20, is designed to bind CD20 with high affinity and CD47 with optimally lowered affinity. As a result of the detuned CD47 affinity, CC-96673 selectively binds to CD20-expressing cells, blocking the interaction of CD47 with SIRPα. This increased selectivity of CC-96673 over monospecific anti-CD47 approaches allows for the use of wild-type IgG1 Fc, which engages activating crystallizable fragment gamma receptors (FcγRs) to fully potentiate macrophages to engulf and destroy CD20+ cells, while sparing CD47+CD20- normal cells. The combined targeting of anti-CD20 and anti-CD47 results in enhanced anti- tumor activity compared to anti-CD20 targeting antibodies alone. Furthermore, preclinical studies have demonstrated that CC-96673 exhibits acceptable pharmacokinetic properties with a favorable toxicity profile in non-human primates. Collectively, these findings define CC-96673 as a promising CD47 × CD20 bispecific antibody that selectively destroys CD20+ cancer cells via enhanced phagocytosis and other effector functions.

Enabling internet of things in road traffic forecasting with deep learning models

Integration of the latest technological advancements such as Internet of Things (IoT) and Computational Intelligence (CI) techniques is an active research area for various industrial applications. The rapid urbanization and exponential growth of vehicles has led to crowded traffic in cities. The deployment of IoT infrastructures for building smart and intelligent traffic management system greatly improves the quality and comfort of city dwellers. This work aims at building a cost effective IoT enabled traffic forecasting system using deep learning techniques. The case study experimentation is done in a real time traffic environment. The main contributions of this work include: (i) deploying road side sensor station built with ultrasonic sensor and Arduino Uno controller for obtaining traffic flow data (ii) building an IoT cloud system based on open source Thingspeak cloud platform for monitoring real time traffic (iii) performing short term traffic forecast using Recurrent Neural Network (RNN) models such as Long Short Term Memory (LSTM) and Gated Recurrent Unit (GRU). The performance of the prediction model is compared with the traditional statistical methods such as Autoregressive Integrated Moving Average (ARIMA), Seasonal ARIMA (SARIMA) and Convolutional Neural Network (CNN). The results show good performance metrics with RMSE of 5.8, 7.9, 10.2 for LSTM model and 6.7, 8.6, 10.9 for GRU model for three different scenarios such as whole day, morning congested hour and evening congested hour datasets.

Review on Stenotrophomonas maltophilia: an emerging multidrug-resistant opportunistic pathogen

Stenotrophomonas maltophilia is an opportunistic pathogen that results in nosocomial infections in immunocompromised individuals. These bacteria colonize on the surface of medical devices and therapeutic equipment like urinary catheters, endoscopes, and ventilators, causing respiratory and urinary tract infections. The low outer membrane permeability of multidrug-resistance efflux systems and the two chromosomally encoded β-lactamases present in S.maltophilia are challenging for arsenal control. The cell-associated and extracellular virulence factors in S.maltophilia are involved in colonization and biofilm formation on the host surfaces. The spread of antibiotic-resistant genes in the pathogenic S.maltophilia attributes to bacterial resistance against a wide range of antibiotics, including penicillin, quinolones, and carbapenems. So far, tetracycline derivatives, fluoroquinolones, and trimethoprim-sulfamethoxazole (TMP-SMX) are considered promising antibiotics against S.maltophilia. Due to the adaptive nature of the intrinsically resistant mechanism towards the number of antibiotics and its ability to acquire new resistance via mutation and horizontal gene transfer, it is quite tricky for medicinal contribution against S.maltophilia. The current review summarizes the literary data of pathogenicity, quorum sensing, biofilm formation, virulence factors, and antibiotic resistance of S.maltophilia.

Formulation and Evaluation of Herbal Baby Shampoo

Shampoos are most probably used as cosmetics. In general, hair care products are used for cleaning scalp and also used for beautifying agents. It contains suitable additives preservatives and active ingredients. The purpose of using shampoo is to remove dirt that is build up on the hair without stripping out much of this bum. The herbal shampoo popularized due to formulated from herbal sources which is safer with milder effect. In this study, herbal shampoo was formulated containing suitable ingredient such as Lawsonia inermis (L) Henna), Azadirachta indica A. Juss. (Neem), Hibiscus rosa-sinensis L (Hibiscus), Ficus benghalensis L.   (Banyan), Phyllanthus emblica L. (Amla), Sapindus mukorossi Gaertn. (Ritha), Senegalia rugata (Lam.) Britton & Rose.  (Shikakai) and Aloe vera (L.) Burm.f. (Aloe vera) different proportions to formulate and evaluate its physicochemical properties. Marketed crude products of the above-mentioned herbal drugs were used in the formulation of herbal shampoo. Ritha and Shikakai when shaken with water create rich foam impact. Amla fruit and Hibiscus rosa-sinensis L. flowers are used to promote hair growth, anti-dandruff agent, strengthen hairs, and prevent hair fall. Dried roots of  Ficus benghalensis (Banyan) produce Lustrous effects on hairs. H. rosa-sinensis flower and Aloe vera (L) used as a conditioning agent and also moisturizing agent. The formulated herbal shampoo was evaluated for its physical and chemical stability.

256 Charcot-Marie-Tooth Disease as A Risk Factor for Periprosthetic Fractures in Tibiotalocalcaneal Fusion With Intramedullary Nailing

Aim

The treatment for severe fixed hindfoot osteoarthritis secondary to Charcot-Marie-Tooth disease (CMT) disease is tibiotalocalcaneal (TTC) arthrodesis. In our centre, we have noticed a disproportionate rate of periprosthetic fractures in CMT patients following TTC arthrodesis with retrograde hindfoot nailing. The aim of this study was to test this hypothesis by evaluating our local cohort of TTC arthrodesis with retrograde hindfoot nailing.

Method

A retrospective review of patients who had TTC arthrodesis with intramedullary nailing was conducted over a seven-year period.

Results

There were 45 patients (30 male, 15 female) in our cohort. Forty-one patients achieved radiological and clinical fusion of their TTC arthrodesis. All three patients who had CMT sustained periprosthetic fracture at the tip of the nail at an average of 4 (range: 2.5 - 6) months from index operation. In comparison, no patients in the rest of the cohort sustained periprosthetic fractures. The nail position of the patients with CMT were central in both planes in all 3 patients. None of the patients with CMT had abutment of the cortex on either planes.

Conclusions

We found that there was a disproportionate rate of periprosthetic fractures in CMT patients in our cohort of TTC arthrodesis with retrograde hindfoot nailing. This suggests that CMT is a significant risk factor. The authors propose a longer nail to reduce the lever arm, with a long period of protected weight bearing till union. Elective removal of the nail to prevent this phenomenon from occurring should also be considered.

Structure of the human marker of self 5-transmembrane receptor CD47

CD47 is the only 5-transmembrane (5-TM) spanning receptor of the immune system. Its extracellular domain (ECD) is a cell surface marker of self that binds SIRPα and inhibits macrophage phagocytosis, and cancer immuno-therapy approaches in clinical trials are focused on blocking CD47/SIRPα interaction. We present the crystal structure of full length CD47 bound to the function-blocking antibody B6H12. CD47 ECD is tethered to the TM domain via a six-residue peptide linker (¹¹⁴RVVSWF¹¹⁹) that forms an extended loop (SWF loop), with the fundamental role of inserting the side chains of W118 and F119 into the core of CD47 extracellular loop region (ECLR). Using hydrogen-deuterium exchange and molecular dynamics simulations we show that CD47's ECLR architecture, comprised of two extracellular loops and the SWF loop, creates a molecular environment stabilizing the ECD for presentation on the cell surface. These findings provide insights into CD47 immune recognition, signaling and therapeutic intervention.

Targeting the Wnt signaling pathway through R-spondin 3 identifies an anti-fibrosis treatment strategy for multiple organs

The Wnt/β-catenin signaling pathway has been implicated in human proliferative diseases such as cancer and fibrosis. The functions of β-catenin and several other components of this pathway have been investigated in fibrosis. However, the potential role of R-spondin proteins (RSPOs), enhancers of the Wnt/β-catenin signaling, has not been described. A specific interventional strategy targeting this pathway for fibrosis remains to be defined. We developed monoclonal antibodies against members of the RSPO family (RSPO1, 2, and 3) and probed their potential function in fibrosis in vivo. We demonstrated that RSPO3 plays a critical role in the development of fibrosis in multiple organs. Specifically, an anti-RSPO3 antibody, OMP-131R10, when dosed therapeutically, attenuated fibrosis in carbon tetrachloride (CCl₄)-induced liver fibrosis, bleomycin-induced pulmonary and skin fibrosis models. Mechanistically, we showed that RSPO3 induces multiple pro-fibrotic chemokines and cytokines in Kupffer cells and hepatocytes. We found that the anti-fibrotic activity of OMP-131R10 is associated with its inhibition of β-catenin activation in vivo. Finally, RSPO3 was found to be highly elevated in the active lesions of fibrotic tissues in mouse models of fibrosis and in patients with idiopathic pulmonary fibrosis (IPF) and nonalcoholic steatohepatitis (NASH). Together these data provide an anti-fibrotic strategy for targeting the Wnt/β-catenin pathway through RSPO3 blockade and support that OMP-131R10 could be an important therapeutic agent for fibrosis.

Abstract 2009: CC-90002 (anti-CD47 antibody) in vivo anti-tumor activity is associated with an increase in M1-polarized macrophages

CD47, also known as integrin-associated protein, is over-expressed in several tumor types, including AML, NHL, breast cancer and multiple myeloma. Elevated expression of CD47 on the cell surface protects tumors from phagocytosis by macrophages through binding to signal regulatory protein alpha (SIRPα) on the surface of macrophages. The CD47-SIRPα interaction triggers events that culminate in the inhibition of the phagocytic process. Macrophages are one of the immune cell types frequently found in the tumor microenvironment and exist as a heterogeneous population that includes both M1 and M2 macrophages. While the spectrum of macrophage subpopulations are likely quite diverse, traditionally, it is thought that M1 macrophages are pro-inflammatory, enhancing immune responses against tumor cells, while M2 macrophages are pro-tumor, since they express a wide array of anti-inflammatory molecules, cytokines and growth factors that promote tumor growth, angiogenesis and an immunosuppressive microenvironment. We evaluated CC-90002 efficacy in the RPMI-8226 multiple myeloma and MDA-MB-231 breast cancer xenograft models and enumerated mouse M1/M2-like macrophage populations within in the tumor before and after C-90002 treatment. In both RPMI-8226 and MDA-MB-231 models, M2 macrophages were the primary resident macrophage. Our studies show that when mice bearing RPMI-8226 multiple myeloma xenografts were treated with CC-90002 (a humanized anti-CD47 antibody), tumor regression was preceded by infiltration of macrophages into the xenograft. In the MDA-MB-231 breast cancer model, resident macrophages appeared to mediate the CC-90002 anti-tumor efficacy in vivo without additional macrophage trafficking. Interestingly, in both models, M1 macrophages appear to mediate CC-90002 efficacy regardless of whether macrophages infiltrate the tumor or are tumor-resident. In the MDA-MB-231 breast cancer model where CC-90002 did not induce infiltration, it is possible that resident tumor macrophages were re-educated to an M1 phenotype. In in vitro experiments using human monocyte-derived macrophages, both M1 and M2 macrophages are able to promote phagocytosis and additionally, we observed that CC-90002 selectively inhibited migration of M2 macrophages toward tumor cell conditioned media. This would presumably shift the overall balance of tumor-associated macrophages toward the M1 phenotype and suggests that inhibiting CD47 can both promote tumor phagocytosis and skew tumor macrophage subpopulations toward an anti-tumor phenotype. CC-90002 is currently being tested in two ongoing Phase I clinical studies in subjects with advanced solid and hematologic cancers (NCT02367196, NCT02641002).

Citation Format: Bing Zheng, Piu Wong, WenQing Yang, Rama Narla, Michael Burgess, Laure Escoubet, Heather Raymon, Kandasamy Hariharan, John Boylan, Kristen Hege, Victoria Sung. CC-90002 (anti-CD47 antibody) in vivo anti-tumor activity is associated with an increase in M1-polarized macrophages [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 2009. doi:10.1158/1538-7445.AM2017-2009

The 100 most cited papers in foot and ankle surgery

BACKGROUND

The number of citations of a paper gives an indication of an article's merit and importance within a medical specialty. We identify and analyse the 100 most cited papers in foot and ankle surgery.

METHOD

The Science Citation Index Expanded was searched for citations in 15 respected journals containing foot and ankle articles. Papers were analysed for subject, authorship, institution, country and year of publication. The average yearly citation was compared to total number of citations.

RESULTS

3501 foot and ankle papers were returned. The maximum number of citations was 1084 and the mean was 104. The top 100 papers were published between 1979 and 2007, with the majority published in the last decade. The ankle was the most important anatomical region discussed, and basic science and degenerative disease were popular topics. We found a large discrepancy between the total number of citations with average yearly citation.

CONCLUSION

Foot and ankle surgery is a young and rapidly developing sub-specialty within orthopaedics. Recently there has been a significant increase in influential papers published. Certain topics are popular indicating their importance within the field. This study highlights important papers in foot and ankle surgery giving an insight into readership.

Galiximab (anti-CD80)-induced growth inhibition and prolongation of survival in vivo of B-NHL tumor xenografts and potentiation by the combination with fludarabine

Galiximab is a primatized monoclonal antibody that targets CD80 expressed on malignant B cells and is being studied in the clinic as a potential treatment for follicular NHL. We have recently reported that galiximab signals B-NHL cells in vitro and inhibits cell growth and sensitizes resistant tumor cells to apoptosis by chemotherapeutic drugs. This study was designed to validate the in vitro findings in in vivo in mice. Thus, we examined in vivo the antitumor activity of galiximab used alone and in combination with chemotherapeutic agents in SCID mice bearing human lymphoma xenografts. The in vivo antitumor effects of galiximab used alone and in combination with fludarabine or doxorubicin were determined in solid and disseminated human B-lymphoma tumors grown in SCID mice. Galiximab monotherapy in vivo demonstrated significant antitumor activity in a Raji lymphoma solid tumor model and in an SKW disseminated lymphoma tumor model. There was significant inhibition in tumor growth and prolongation of survival. In vitro, galiximab sensitized Raji cells to apoptosis by both fludarabine and doxorubicin. Tumor growth inhibition was significantly enhanced when the mice were treated with the combination of galiximab and fludarabine. These findings support the potential clinical application of galiximab in combination with chemotherapeutic drugs for the treatment of CD80-expressing hematological malignancies.

Destructive post-traumatic chondrolysis of the subtalar joint: a case report and review of the literature

Injuries to the subtalar joint are often associated with fractures of the talus or calcaneum. These injuries often lead to degenerative changes resulting in pain, restriction of movement and difficulty in weight bearing. This can cause significant deformity and disability for the patient. Occult injury of the subtalar joint has been described as an isolated event or in association with a subluxation/dislocation of this joint. They are difficult to assess with plain radiography therefore, they are generally diagnosed with advanced imaging like CT scan or MRI scan. We present a case of a 66-year-old man who presented with destructive chondrolysis of the subtalar joint 2 years following conservative treatment of a minimally displaced distal fibular fracture. It was treated by subtalar and talonavicular arthrodesis. Overall, the patient made an excellent recovery and was satisfied with the outcome.

Abstract 766: Galiximab disrupts the dysregulated NF-κB/YY1/Snail/BclXL circuit that regulates the resistance of B-NHL cell lines: Sensitization to chemo-immunotherapeutic drugs

The combination of Rituximab and chemotherapy is currently the standard treatment for several B-NHL malignancies. However, there is a subset of patients that does not initially respond and a subset that fails to respond to further treatment. Therefore, there is an urgent need to develop new therapeutic modalities for those patients. Galiximab (anti-CD80 mAb) has been developed with the objective of overcoming the resistance to rituximab and/or used in combination with rituximab to improve response rates. A Phase II double blind placebo controlled trial of rituximab+galiximab vs. rituximab+placebo in 337 subjects with relapsed or refractory, grade I-IIIa, follicular NHL in relapse were followed up of 13.8 month. The addition of Galiximab to rituximab reduced the hazard for disease progression or death by 26% compared to the rituximab+placebo group. However, the mechanisms by which Galiximab mediates its effects have not been examined. Preliminary findings demonstrated that treatment of B-NHL cell lines with Galiximab resulted in the inhibition of cell growth and sensitization of drug-resistant tumor cells to both CDDP and TRAIL-mediated apoptosis. Sensitization was a result of Galiximab-induced inhibition of the constitutively activated NF-κB pathway and downstream the resistant factors Yin Yang 1 (YY1), Snail, and BclXL. The role of each of these factors in the regulation of resistance and whether they also regulate each other were assessed by transfection with siRNAs. Treatment of Raji (CD80+) Burkitt's Lymphoma cell line with YY1 siRNA resulted in the inhibition of YY1, Snail, phospho-p65, and BclXL as assessed by western. Likewise, transfection with Snail siRNA resulted in the inhibition of Snail, YY1, phospho-p65, and BclXL. In both cases, the transfected cells resulted in the reversal of resistance and sensitization to apoptosis by both CDDP and TRAIL. These findings revealed that NF-κB regulates YY1, Snail, and BclXL and that both YY1 and Snail, in turn, regulate NF-κB and BclXL. It has been reported that YY1 regulates NF-κB via miR29 and, in turn, NF-κB regulates YY1 transcription. Also, YY1 regulates Snail transcription. However, it is not known how does Snail regulate NF-κB and YY1. We speculate that Snail regulates phospho-p65 via transcription or indirectly through the regulation of NF-κB by YY1. The present findings reveal a new dysregulated NF-κB/YY1/Snail/BclXL circuit in the regulation of resistance of B-NHL to cytotoxic drugs. Galiximab interferes with this circuit and results in the reverse of resistance. In addition, the findings revealed new targets that may be of prognostic significance as well as targets for therapy. The present findings in B-NHL cell lines may be also generalized to non-lymphoid malignancies.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 766. doi:1538-7445.AM2012-766

Galiximab signals B-NHL cells and inhibits the activities of NF-κB-induced YY1- and snail-resistant factors: mechanism of sensitization to apoptosis by chemoimmunotherapeutic drugs

Galiximab (anti-CD80 monoclonal antibody) is a primatized (human IgG1 constant regions and cynomologus macaque variable regions) monoclonal antibody that is currently in clinical trials. Galiximab inhibits tumor cell proliferation through possibly cell signaling-mediated effects. Thus, we hypothesized that galiximab may signal the tumor cells and modify intracellular survival/antiapoptotic pathways such as the NF-κB pathway. This hypothesis was tested using various CD80(+) Burkitt B-NHL (non-Hodgkin lymphomas) cell lines as models. Treatment of B-NHL cells with galiximab (25-100 μg/mL) resulted in significant inhibition of NF-κB activity and its target resistant factors such as YY1, Snail, and Bcl-2/Bcl-XL. Treatment of B-NHL cells with galiximab sensitized the tumor cells to both cis-diamminedichloroplatinum(II) (CDDP)- and TRAIL-induced apoptosis. The important roles of YY1- and Snail-induced inhibition by galiximab in the sensitization to CCDP and TRAIL were corroborated following transfection of Raji cells with YY1 or Snail short interfering RNA. The transfected cells were shown to become sensitive to both CCDP- and TRAIL-induced apoptosis in the absence of galiximab. Furthermore, knockdown of YY1 or Snail inhibited Bcl-XL. The involvement of Bcl-XL inhibition in sensitization was corroborated by the use of the pan-Bcl-2 inhibitor 2MAM-3 whereby the treated cells were sensitive to both CDDP- and TRAIL-induced apoptosis. These findings show that galiximab inhibits the NF-κB/Snail/YY1/Bcl-XL circuit that regulates drug resistance in B-NHL and in combination with cytotoxic drugs results in apoptosis. The findings also support the therapeutic application of the combination of galiximab and cytotoxic drugs in the treatment of drug-resistant CD80-positive B-cell malignancies.

Weil osteotomy: assessment of medium term results and predictive factors in recurrent metatarsalgia

BACKGROUND

The angle of the Weil osteotomy is usually referenced relative to the floor irrespective of the plantar angulation of the metatarsal. This study aims to analyse the long term results following the Weil osteotomy and identify the cause of poor outcome.

METHODS

This study presents a retrospective review of 61 patients (86 feet), with mean follow-up of 31 months. Each patient underwent clinical, pedobarographic and radiological examination. The radiographs obtained included 'Metatarsal Skyline Views' (MSV), to assess the plantar declination of the metatarsal heads following the osteotomy. The functional scoring was performed using AOFAS and Foot Function Index.

RESULTS

Fifty-five patients (80 feet) showed good to excellent results clinically. Six patients had persistent metatarsalgia. All these 6 patients had callosities beneath metatarsal heads. Pedobarography showed peak pressures in the same distribution as callosities and the MSV showed increased plantar declination of the metatarsal heads. This correlation was found to be significant (p<0.05).

CONCLUSION

The Weil osteotomy is a safe and effective treatment for metatarsalgia. An MSV radiograph is helpful to identify the plantar prominence of metatarsal which can be associated with poor clinical outcomes.

Emerging antibody combinations in oncology

The use of monoclonal antibodies (mAbs) has become a general approach for specifically targeting and treating human disease. In oncology, the therapeutic utility of mAbs is usually evaluated in the context of treatment with standard of care, as well as other small molecule targeted therapies. Many anti-cancer antibody modalities have achieved validation, including the targeting of growth factor and angiogenesis pathways, the induction of tumor cell killing or apoptosis, and the blocking of immune inhibitory mechanisms to stimulate anti-tumor responses. But, as with other targeted therapies, few antibodies are curative because of biological complexities that underlie tumor formation and redundancies in molecular pathways that enable tumors to adapt and show resistance to treatment. This review discusses the combinations of antibody therapeutics that are emerging to improve efficacy and durability within a specific biological mechanism (e.g., immunomodulation or the inhibition of angiogenesis) and across multiple biological pathways (e.g., inhibition of tumor growth and induction of tumor cell apoptosis).

A stable IgG-like bispecific antibody targeting the epidermal growth factor receptor and the type I insulin-like growth factor receptor demonstrates superior anti-tumor activity

The epidermal growth factor receptor (EGFR) and the type I insulin-like growth factor receptor (IGF-1R) are two cell surface receptor tyrosine kinases known to cooperate to promote tumor progression and drug resistance. Combined blockade of EGFR and IGF-1R has shown improved anti-tumor activity in preclinical models. Here, we report the characterization of a stable IgG-like bispecific antibody (BsAb) dual-targeting EGFR and IGF-1R that was developed for cancer therapy. The BsAb molecule (EI-04), constructed with a stability-engineered single chain variable fragment (scFv) against IGF-1R attached to the carboxyl-terminus of an IgG against EGFR, displays favorable biophysical properties for biopharmaceutical development. Biochemically, EI-04 bound to human EGFR and IGF-1R with sub nanomolar affinity, co-engaged the two receptors simultaneously, and blocked the binding of their respective ligands with similar potency compared to the parental monoclonal antibodies (mAbs). In tumor cells, EI-04 effectively inhibited EGFR and IGF-1R phosphorylation, and concurrently blocked downstream AKT and ERK activation, resulting in greater inhibition of tumor cell growth and cell cycle progression than the single mAbs. EI-04, likely due to its tetravalent bispecific format, exhibited high avidity binding to BxPC3 tumor cells co-expressing EGFR and IGF-1R, and consequently improved potency at inhibiting IGF-driven cell growth over the mAb combination. Importantly, EI-04 demonstrated enhanced in vivo anti-tumor efficacy over the parental mAbs in two xenograft models, and even over the mAb combination in the BxPC3 model. Our data support the clinical investigation of EI-04 as a superior cancer therapeutic in treating EGFR and IGF-1R pathway responsive tumors.

Stable IgG-like bispecific antibodies directed toward the type I insulin-like growth factor receptor demonstrate enhanced ligand blockade and anti-tumor activity

Bispecific antibodies (BsAbs) target multiple epitopes on the same molecular target or different targets. Although interest in BsAbs has persisted for decades, production of stable and active BsAbs has hindered their clinical evaluation. Here, we describe the production and characterization of tetravalent IgG-like BsAbs that combine the activities of allosteric and competitive inhibitors of the type-I insulin-like growth factor receptor (IGF-1R). The BsAbs, which were engineered for thermal stability, express well, demonstrate favorable biophysical properties, and recognize both epitopes on IGF-1R. Only one BsAb with a unique geometry, denoted BIIB4-5scFv, was capable of engaging all four of its binding arms simultaneously. All the BsAbs (especially BIIB4-5scFv) demonstrated enhanced ligand blocking over the single monoclonal antibodies (mAbs), particularly at high ligand concentrations. The pharmacokinetic profiles of two IgG-like BsAbs were tested in nude mice and shown to be comparable with that of the parental mAbs. The BsAbs, especially BIIB4-5scFv, demonstrated an improved ability to reduce the growth of multiple tumor cell lines and to inhibit ligand-induced IGF-1R signaling in tumor cells over the parental mAbs. BIIB4-5scFv also led to superior tumor growth inhibition over its parental mAbs in vivo. In summary, BsAbs that bridge multiple inhibitory mechanisms against a single target may generally represent a more effective strategy for intervention in oncology or other indications compared with traditional mAb therapy.

Combination of two insulin-like growth factor-I receptor inhibitory antibodies targeting distinct epitopes leads to an enhanced antitumor response

The insulin-like growth factor-I receptor (IGF-IR) is a cell surface receptor tyrosine kinase that mediates cell survival signaling and supports tumor progression in multiple tumor types. We identified a spectrum of inhibitory IGF-IR antibodies with diverse binding epitopes and ligand-blocking properties. By binding distinct inhibitory epitopes, two of these antibodies, BIIB4 and BIIB5, block both IGF-I and IGF-II binding to IGF-IR using competitive and allosteric mechanisms, respectively. Here, we explored the inhibitory effects of combining BIIB4 and BIIB5. In biochemical assays, the combination of BIIB4 and BIIB5 improved both the potency and extent of IGF-I and IGF-II blockade compared with either antibody alone. In tumor cells, the combination of BIIB4 and BIIB5 accelerated IGF-IR downregulation and more efficiently inhibited IGF-IR activation as well as downstream signaling, particularly AKT phosphorylation. In several carcinoma cell lines, the antibody combination more effectively inhibited ligand-driven cell growth than either BIIB4 or BIIB5 alone. Notably, the enhanced tumor growth-inhibitory activity of the BIIB4 and BIIB5 combination was much more pronounced at high ligand concentrations, where the individual antibodies exhibited substantially reduced activity. Compared with single antibodies, the BIIB4 and BIIB5 combination also significantly further enhanced the antitumor activity of the epidermal growth factor receptor inhibitor erlotinib and the mTOR inhibitor rapamycin. Moreover, in osteosarcoma and hepatocellular carcinoma xenograft models, the BIIB4 and BIIB5 combination significantly reduced tumor growth to a greater degree than each single antibody. Taken together, our results suggest that targeting multiple distinct inhibitory epitopes on IGF-IR may be a more effective strategy of affecting the IGF-IR pathway in cancer.

Rituximab-mediated cell signaling and chemo/immuno-sensitization of drug-resistant B-NHL is independent of its Fc functions

PURPOSE

Rituximab [chimeric anti-CD20 monoclonal antibody], alone or combined with chemotherapy, is used in the treatment of non-Hodgkin's lymphoma (NHL). Rituximab binds to CD20 and inhibits intracellular survival/growth pathways leading to chemo/immunosensitization of tumor cells in vitro. The contribution of rituximab Fc-FcR interaction in signaling is not known. This study examined the role of Fc-FcR interactions in rituximab-induced signaling using rituximab (Fab')(2) fragments as well as rituximab devoid of the CH2 Fc-binding domain (CH2(-)).

EXPERIMENTAL DESIGN

Rituximab (CH2(-)) and rituximab (Fab')(2) were tested for their activity on B-NHL cell lines. Cell signaling and sensitization to chemotherapy and immunotherapy were examined. The in vitro studies were validated in mice bearing tumor xenografts.

RESULTS

Although the modified antibodies were defective in antibody-dependent cellular cytotoxicity and complement-dependent cytotoxicity functions, they retained all other biological activities such as inhibition of cell proliferation, induction of cell aggregation, and apoptosis induction. In addition, similar to rituximab, the modified antibodies inhibited the activity of cell survival/growth pathways and their associated transcription factors (e.g., NF-kappaB, YY1, SP-1), and signal transducers and activators of transcription 3 (STAT-3), and downregulated the expression of antiapoptotic gene products, such as Bcl-2/Bcl(xl), which regulate drug resistance. The modified antibodies, similar to rituximab, sensitized resistant B-NHL cells to both CDDP and Fas ligand-induced apoptosis. Furthermore, treatment of nude mice bearing Raji tumor cell xenografts with the combination of rituximab (Fab')(2) or rituximab and CDDP resulted in similar and significant inhibition of tumor growth.

CONCLUSION

These findings reveal that rituximab-mediated inhibition of intracellular signaling pathways and leading to chemo/immuno-sensitization of resistant B-NHL is Fc independent.

Characterization of inhibitory anti-insulin-like growth factor receptor antibodies with different epitope specificity and ligand-blocking properties: implications for mechanism of action in vivo

Therapeutic antibodies directed against the type 1 insulin-like growth factor receptor (IGF-1R) have recently gained significant momentum in the clinic because of preliminary data generated in human patients with cancer. These antibodies inhibit ligand-mediated activation of IGF-1R and the resulting down-stream signaling cascade. Here we generated a panel of antibodies against IGF-1R and screened them for their ability to block the binding of both IGF-1 and IGF-2 at escalating ligand concentrations (>1 microm) to investigate allosteric versus competitive blocking mechanisms. Four distinct inhibitory classes were found as follows: 1) allosteric IGF-1 blockers, 2) allosteric IGF-2 blockers, 3) allosteric IGF-1 and IGF-2 blockers, and 4) competitive IGF-1 and IGF-2 blockers. The epitopes of representative antibodies from each of these classes were mapped using a purified IGF-1R library containing 64 mutations. Most of these antibodies bound overlapping surfaces on the cysteine-rich repeat and L2 domains. One class of allosteric IGF-1 and IGF-2 blocker was identified that bound a separate epitope on the outer surface of the FnIII-1 domain. Using various biophysical techniques, we show that the dual IGF blockers inhibit ligand binding using a spectrum of mechanisms ranging from highly allosteric to purely competitive. Binding of IGF-1 or the inhibitory antibodies was associated with conformational changes in IGF-1R, linked to the ordering of dynamic or unstructured regions of the receptor. These results suggest IGF-1R uses disorder/order within its polypeptide sequence to regulate its activity. Interestingly, the activity of representative allosteric and competitive inhibitors on H322M tumor cell growth in vitro was reflective of their individual ligand-blocking properties. Many of the antibodies in the clinic likely adopt one of the inhibitory mechanisms described here, and the outcome of future clinical studies may reveal whether a particular inhibitory mechanism leads to optimal clinical efficacy.

Crystallization kinetics and phase transformation in superionic lithium metaphosphate (Li(2)O-P(2)O(5)) glass system

The ionic conductivity of mol% 50Li(2)O-50P(2)O(5) melt quenched glass shows an anomalous increase after its glass transition temperature (T(g)) around 590 K. On further increasing the temperature gradually, the conductivity decreases owing to the devitrification of Li(2)O-P(2)O(5) glass. The evolution of devitrified crystallites was evidenced by XRD patterns. To understand the devitrification process, isothermal and non-isothermal DSC studies have been carried out on mol% 50Li(2)O-50P(2)O(5) glass. T(g) as well as T(c) values are found to increase monotonically with increasing heating rates. Variation of T(g) as a function of heating rates has been investigated to evaluate the lower limiting temperature of T(g) and the activation energy for structural relaxation. Results of the DSC studies indicate (i) single-stage bulk crystallization of the glass, with DSC traces exhibiting a single [Formula: see text] transition, (ii) an order parameter (Avrami constant) of 2.8 ± 0.1, suggesting internal (bulk) crystallization of the glass, (iii) an activation energy for crystallization equal to 121.7 kJ mol(-1) and (iv) the activation energy for structural relaxation, E(g), to be 558.8 kJ mol(-1). The crystallization mechanism is closely associated with the JMA model and the experimental dataset have been fitted to a non-isothermal Avrami expression and the obtained parameters confirm the experimental results.

Lumiliximab (anti-CD23 antibody) mediates apoptosis and antitumor activity in chronic lymphocytic leukemia (CLL) cells and CD23+ lymphoma cell lines

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Background: Given the success of treating CLL with antibody therapies, interest in those directed at alternative B-cell antigens remains high. Lumiliximab is a chimeric macaque and human anti-CD23 monoclonal antibody whose antigen is expressed on almost all CLL cells. Methods: We examined lumiliximab’s ability to mediate direct apoptosis, antibody-dependent cellular cytotoxicity (ADCC), and complement-dependent cytotoxicity (CDC) against primary CLL cells and CD23+ B-cell lines. Apoptosis was measured with a flow-cytometry based assay for active caspase-3. ADCC was determined by 51Cr-release assay. CDC assays were performed in the presence of 30% autologous plasma from patients and quantified by propidium iodide staining. Western blotting analysis was used to monitor protein expression before and after treatment with lumiliximab. The CD23+ human lymphoma SKW6.4 cell line was used for in vivo evaluation of lumiliximab in a disseminated human lymphoma model. Results: Lumiliximab mediates apoptosis, ADCC, and CDC in CD23+ B-cell lines. However, in primary CLL cells, the primary mechanism of cell killing appears to be mediated via apoptosis. Apoptosis induced by lumiliximab occurs mainly through the intrinsic pathway used by other CLL therapies. Lumiliximab decreased expression of Bcl-2 and XIAP and inhibited Akt activation in CLL cells. Lumiliximab when combined in vitro or in vivo with rituximab or fludarabine effectively mediates synergistic cytotoxicity against primary CLL cells and CD23+ B-cell lines. Significant antitumor activity was also observed with lumiliximab vs a control antibody in a SCID mouse model of human B-cell lymphoma (P <.01). More importantly, lumiliximab + rituximab or lumiliximab + fludarabine results in prolonged survival vs lumiliximab, rituximab, or fludarabine single-agent treatment. Conclusions: These results indicate that lumiliximab induces apoptosis by activating caspases and downregulating antiapoptotic proteins, and suggest that in combination with rituximab or chemotherapy, lumiliximab synergistically enhances antitumor activity in CLL or other B-cell malignancies in which this antigen is overexpressed.

No significant financial relationships to disclose.

Indications for and technique of first metatarsophalangeal joint arthroscopy

BACKGROUND

Arthroscopy of the great toe metatarsophalangeal joint has been used for a variety of indications, ranging from synovitis to osteochondral defects. The purpose of the present study was to define the indications for arthroscopy, assess its efficacy, and demonstrate the limitations of this procedure.

METHODS

Hallux metatarsophalangeal joint arthroscopy was used in 20 patients (25 feet). Indications included degenerative disease with early osteophytosis, chondromalacia, osteochondral defects, loose bodies, arthrofibrosis, synovitis, gouty arthritis, first metatarsophalangeal joint pain with no obvious findings clinically and radiographically in young adults, and intra-articular fracture of the first metatarsophalangeal joint. All patients had a minimal followup of 2 years and were evaluated clinically and radiographically.

RESULTS

Arthroscopic surgery resulted in pain free first metatarsophalangeal joints in 95% (19 of 20 patients). Patients with degenerative disease had a pain-free joint for a minimum of 2 years. The patients with gouty arthritis and intra-articular fracture had good functional outcomes. Arthroscopy also helped in identifying the pathology in painful joints with no obvious radiographic features that included conditions such as 'meniscoid' and other impingement lesions.

CONCLUSION

Arthroscopy of the first metatarsophalangeal joint is not suitable for patients with extensive degenerative changes and large osteophytes and those that require cheilectomy or arthrodesis. Arthroscopic management of certain painful hallucal metatarsophalangeal joints is a specialized technique, which if performed for the right indications, gives a favorable outcome with minimal complications.

Histidine metabolism in experimental protein malnutrition in rats

1. The activities of the enzymes histidase, urocanase and histidine-pyruvate transaminase were studied in rats under conditions of protein malnutrition. Urocanase and histidase activities in liver were markedly lowered in experimental protein malnutrition, but the activity of histidine-pyruvate transaminase was unaffected. There is a metabolic control in vivo of the enzymes involved in the catabolism of histidine. 2. Significant changes in the urinary excretion of histidine, composition of liver and serum were apparent in the protein-malnourished rat. 3. The changes in the activities of the enzymes and other parameters were of a reversible nature and dependent on the nature of the dietary protein. 4. The significance of these findings is discussed in relation to abnormal histidine metabolism in kwashiorkor.

Differential requirements for CTL generation by novel immunostimulants: APC tropism, use of the TAP-independent processing pathway, and dependency on CD80/CD86 costimulation

A major drawback of subunit vaccines is their inability to generate cytolytic T lymphocytes (CTL), a deficit attributed to segregation of the class I and class II antigen-processing pathways. We sought to understand processes involved in CTL induction by three proprietary adjuvants: Tomatine, PROVAX, and a synthesized glycolipid (Glc-N-(8/16), Glycolipid). We used in vivo models to investigate antigen uptake, macrophage involvement, TAP-independent processing, and costimulatory molecule dependencies. Glycolipid required splenic and lymph node macrophages, whereas Tomatine generated CTL independently of either macrophage population. In contrast, PROVAX showed partial macrophage requirements. Immunized TAP knockout mice revealed that ovalbumin (OVA)-Tomatine and OVA-PROVAX, but not OVA-Glycolipid, generate class I-peptide complexes. All three immunostimulants also elicited CD86-dependent TH1 cytokine responses.

Future of monoclonal antibodies in the treatment of hematologic malignancies

BACKGROUND

The approval of monoclonal antibodies (MAbs) as antibody-targeted therapy in the management of patients with hematologic malignancies has led to new treatment options for this group of patients. The ability to target antibodies to novel functional receptors can increase their therapeutic efficacy.

METHODS

The authors reviewed improvements in MAb design to enhance their effectiveness over the existing therapeutic MAb currently approved for treating hematologic malignancies.

RESULTS

Three classes of therapeutic MAbs showing promise in human clinical trials for treatment of hematologic malignancies include unconjugated MAb, drug conjugates in which the antibody preferentially delivers a potent cytotoxic drug to the tumor, and radioactive immunotherapy in which the antibody delivers a sterilizing dose of radiation to the tumor.

CONCLUSIONS

A better appreciation of how MAbs are metabolized in the body and localized to tumors is resulting in the development of new antibody constructs with improved biodistribution profiles.

A humanized anti-human CD154 monoclonal antibody blocks CD154-CD40 mediated human B cell activation

Humanized anti-CD154 antibody, IDEC-131, had a slightly, but reproducibly, better binding affinity for CD154 (Kd = 5.6 nM), compared to the parent antibody 24-31 (Kd = 8.5 nM). Otherwise it was indistinguishable from the murine parent antibody in its ability to bind to CD154, block CD154 binding to CD40 and inhibit T cell-dependent B cell differentiation. The latter activity was independent of FcR binding as the Fab'1 fragment of IDEC-131 had an equivalent biological activity to that of the whole antibody. IDEC-131 blocked soluble CD154 from inducing proliferation of purified B cells, and blocked T cell dependent anti-tetanus toxoid specific antibody production by human B cells in vitro. IDEC-131, gamma1, kappa, had strong Fc gammaRI, Fc gammaRII and C1q binding, but was unable to induce complement dependent (CDC) or antibody dependent cell-cytotoxicity (ADCC) of activated peripheral blood T cells, which express relatively low levels of CD154. IDEC-131 antibody inhibited both primary and secondary antibody responses to ovalbumin in cynomolgus monkeys at a dose of 5 mg/kg. In non-immunized animals, treatment with IDEC-131 at 50 mg/kg weekly for 13 weeks induced no change in any of the measured lymphocyte subsets, including B cells, CD4+ and CD8+ T cells. Similarly, a safety study in chimpanzees showed no discernible safety related issues at 20 mg/kg, including B and T cell subsets. These results show that the humanized anti-CD154 antibody, IDEC-131, has retained the affinity and functional activity of its murine parent antibody, is unlikely to deplete CD154 positive lymphocytes in humans, and is safe and effective in blocking antibody production in monkeys. Based on its safety and efficacy profile, IDEC-131 is being developed for therapy of systemic lupus erythematosus.

Steroids in idiopathic pulmonary fibrosis: a prospective assessment of adverse reactions, response to therapy, and survival

PURPOSE

We evaluated the risk and potential benefit of high-dose corticosteroid therapy in patients with idiopathic pulmonary fibrosis.

SUBJECTS AND METHODS

We prospectively studied 41 patients with previously untreated, biopsy-proven idiopathic pulmonary fibrosis. Before treatment, we calculated clinical, radiographic, and physiologic severity-of-illness scores for each patient. We scored high-resolution computerized tomographic (CT) scans for ground glass and interstitial opacity. We determined the extent of cellular infiltration, interstitial fibrosis, desquamation, and granulation in open lung biopsy samples. Patients were monitored monthly for steroid-related side effects, response to therapy at 3 months, and mortality.

RESULTS

All patients experienced at least one steroid-induced side effect. Eleven (27%) patients were nonresponders, 11 (27%) were responders, and 19 (46%) remained stable. Of the 19 patients who died during a mean (+/- SD) follow-up of 3.3 +/- 2.3 years, 8 (42%) lost weight during the initial 3 months of steroid therapy; only 3 (14%) of the 22 patients still living (P = 0.08) experienced weight loss. In a multivariate analysis, greater fibrosis (hazard ratio [HR] = 1.4 per unit increase; 95% confidence interval [CI]: 1.0 to 1.9; P = 0.03) and cellularity (RR = 1.9 per unit increase; 95% CI: 1.3 to 2.8; 3, P <0.001) in the biopsy sample and whether a patient was classified as a responder (RR = 0.4 versus nonresponder; 95% CI: 0.2 to 1.0; P = 0.05) or stable (RR = 0.2 versus nonresponder; 95% CI: 0.1 to 0.6, P <0.001) after steroid therapy were associated with mortality.

CONCLUSION

Corticosteroid treatment for idiopathic pulmonary fibrosis is associated with substantial morbidity. Patients who remain stable or respond to corticosteroid therapy have better survival than those who fail to respond. Whether this difference reflects an effect of treatment or less severe disease can be determined only in a randomized trial.

Modification of the Fc region of a primatized IgG antibody to human CD4 retains its ability to modulate CD4 receptors but does not deplete CD4(+) T cells in chimpanzees

Keliximab, a Primatized IgG1 CD4 mAb, was reconfigured to an IgG4 antibody. The gamma4 constant region was further modified by substituting glutamic acid for serine at position 235 in the CH2 domain (IgG4-E), to remove residual binding to Fcgamma receptors, and substitution of serine with proline at position 228 in the hinge region (IgG4-PE) for greater stability. Pharmacokinetic analysis in rats gave a t(1/2) of approximately 4 days for IgG4-E and 9 days for IgG4-PE, consistent with a greater stability of the IgG4-PE molecule. The effects on T cell subsets were assessed in chimpanzees given escalating doses of IgG4-PE: 0.05 mg/kg on Day 16, 1.5 mg/kg dose on Day 43, and 15 mg/kg on Day 85. Receptor modulation was observed at the two highest doses, but no depletion of T cells at any dose. The in vitro and in vivo results demonstrate the potential of this IgG4-PE mAb for use in human trials.

In vitro IgE inhibition in B cells by anti-CD23 monoclonal antibodies is functionally dependent on the immunoglobulin Fc domain

CD23, the low affinity receptor for IgE (FcvarepsilonRII), is involved in regulation of IgE synthesis by B-lymphocytes. Five monoclonal antibodies to human CD23 were generated from cynomolgus macaques immunized with purified soluble CD23 (sCD23). Four of the five primate antibodies blocked the binding of IgE complexes to CD23 positive cells and also inhibited the production of IgE in vitro by IL-4 induced human peripheral blood mononuclear cells (PBMC). The variable domains of several primate antibodies were utilized to construct chimeric macaque/human (PRIMATIZED((R))) monoclonal antibodies. PRIMATIZED((R)) p5E8G1, containing human gamma 1 constant region, inhibited IgE production in vitro as efficiently as the parent primate antibody, but the human gamma 4 constant version, PRIMATIZED((R)) p5E8G4, was not as effective in IgE inhibition. An F(ab')(2) of p5E8G1 did not inhibit IgE production but did interfere with IgE inhibition by the intact anti-CD23 antibody in a dose dependent fashion. The murine monoclonal antibody MHM6 recognizes human CD23 at a different epitope than primate antibody 5E8, and inhibits IgE production by IL-4 induced PBMC. As with the F(ab')(2) of p5E8G1, the F(ab')(2) of MHM6 also failed to inhibit IgE production. These data imply that the mechanism by which anti-CD23 antibodies inhibit IgE production requires cross-linking of CD23 to an IgG receptor. These data also imply that neither bivalent cross-linking of CD23 alone or inhibition of CD23 binding to its natural ligands is sufficient to inhibit IgE production.

Identification of murine cytotoxic T-lymphocyte epitopes of bovine herpesvirus 1

Major histocompatibility complex (MHC) class I molecules present endogenously derived viral peptides to CD8+ cytotoxic T-lymphocytes (CTLs). The objective of this study was to identify the H-2Dd- and H-2Kd-restricted CTL epitopes of bovine herpesvirus 1 (BHV-1), based on the allele-specific peptide motifs (ASPMs) of the above class I molecules. Nine sequences conforming to the H-2Dd and H-2Kd ASPMs were identified on BHV-1 proteins, and the respective peptides were synthesized. Five of these peptides exhibited moderate to strong binding to the Dd molecule. CTLs generated by BALB/c mice immunized with BHV-1 proteins emulsified in a suitable adjuvant effectively lysed peptide-pulsed syngeneic targets, indicating that these epitopes were generated in vivo. Mice immunized with these peptides emulsified in a suitable adjuvant also developed anti-BHV-1 CTLs. These CTLs identified three veritable CTL epitopes among the "potential epitopes" synthesized based on the ASPMs. The elucidation of the CTL epitopes of BHV-1 should aid in the development of efficacious vaccines against this virus.

Tumor regression in mice following vaccination with human papillomavirus E7 recombinant protein in PROVAX

Induction of CD8+ cytotoxic T lymphocytes (CTLs) specific for human papillomavirus (HPV) antigens provides an attractive strategy for immunotherapy of HPV-related cancers in humans. In this study, we investigated the potential of utilizing soluble E7 protein of HPV 16 in an adjuvant formulation, PROVAX as a vaccine against a progressively growing E7 transfected K1735-X21 (H-2k) metastatic melanoma cells (HOPE2) in a mouse model. Vaccination of HOPE2 tumor bearing mice (C3H) with E7 protein in PROVAX resulted in significant inhibition of tumor growth, compared to mice vaccinated with E7 in Alum or saline. In vivo depletion of CD8+ or CD4+ cells indicated that CD8+ cells are the major effector cells in mediating the anti-tumor activity in this model. Furthermore, E7-specific CTL activity in vitro was detected in tumor bearing mice vaccinated with E7-PROVAX. Our studies suggest that recombinant HPV antigens in combination with PROVAX could serve as an effective subunit vaccine to stimulate tumor specific CD8+ T cell mediated immunity against HPV-related cancers.

Influence of partial replacement of butter fat with peanut oil (in infant formula) on erythrocyte fatty acids in infants

Erythrocyte fatty acid composition was studied in infants fed with three different formulae: formula I containing 20% butter fat; formula II containing 10% butter fat and 10% peanut oil; and formula III containing 10% butter fat and 5% peanut oil with a fat content itself reduced to 15%. The linoleic acid levels were 2.5, 18 and 13% in formula I-III, respectively. Analysis of fatty acids at the time of birth, and 3 and 6 months thereafter, indicated that linoleic acid levels could be improved by supplementation with peanut oil. Arachidonic acid levels (20:4, n-6) did not show a proportional relationship with respect to linoleic acid intake. The other ratio such as triene/tetraene, oleic/linoleic, linoleic/arachidonic and arachidonic/linoleic were all within the normal range, indicating normal desaturase and elongase activity. Thus, our present study suggests that peanut oils could be used for enhancing the linoleic acid levels in infants.

Chimeric anti-CD20 (IDEC-C2B8) monoclonal antibody sensitizes a B cell lymphoma cell line to cell killing by cytotoxic drugs

More than 50% of patients with aggressive B lymphomas and the majority of patients with low grade lymphomas are not cured by current therapeutic strategies. The lymphomas express the B cell antigen CD20 on the cell surface and this antigen serves as target for antibody-directed therapies. Clinical studies with encouraging results have been underway with the use of a chimeric anti-CD20 antibody (IDEC-C2B8), consisting of human IgG1-6 constant regions and variable regions from the murine monoclonal anti-CD20 antibody IDEC-2B8. This study investigated the potential anti-tumor therapeutic value of combination treatment with anti-C2B8 and cytotoxic drugs. The in vitro study examined the sensitizing effect of C2B8 antibody on the DHL-4 B lymphoma line to various cytotoxic agents. Cytotoxicity was determined by the MTT assay. Surface and cytoplasmic proteins were determined by flow cytometry. Pretreatment of DHL-4 with C2B8 resulted in inhibition of cell proliferation and cell death and a fraction of the cells underwent apoptosis. While the DHL-4 tumor cells were relatively resistant to several cytotoxic drugs, pretreatment with C2B8 rendered the cells sensitive to TNF-alpha, ricin, diphtheria toxin (DTX), adriamycin and cisplatin but not to VP-16. Chemosensitization of DHL-4 tumor cells was not due to downmodulation of either the MDR-1 or bcl-2 gene products. However, treatment of DHL-4 with C2B8 inhibited TNF-alpha secretion. These findings demonstrate that C2B8 antibody potentiates the sensitivity of DHL-4 tumor cells to several cytotoxic agents. Further, the findings suggest that combination treatments with C2B8 antibody and drugs may be of clinical benefit in the treatment of patients with resistant aggressive B lymphomas.

Effect of high fat diets with and without cholesterol on erythrocyte and tissue fatty acids in rats

Male weanling wistar rats were fed synthetic diets containing 20% safflower oil (SFO) or palm oil (PO) with and without cholesterol for a period of six weeks. Erythrocyte membranes were isolated and their fatty acid composition were determined at the end of the experiment. Besides the fatty acid composition of the kidney and spleen lipids were also determined. Erythrocyte membrane, kidney fatty acids of rats fed safflower oil (SFO) had in the majority of variants a higher level of n-6 fatty acids when compared to palm oil group. However, in the spleen, the level of n-6 fatty acids in the palm oil groups were higher than in the safflower oil group. In general the arachidonic acid [20:4 (n-6)] levels were higher in the spleen and erythrocytes particularly in the cholesterol fed groups when compared to the kidney levels. Palm oil fed rats had a higher level of palmitic (16:0) and oleic [18:1 (n-9)] acids. Rats fed diets containing cholesterol significantly reduced the level of stearic (18:0) but increased the level of oleic [18:1 (n-9)], linoleic [18:2 (n-3)], and arachidonic acids [20:4 (n-6)]. The ratios such as 18:1 (n-9)/18:2 (n-6), 18:1 (n-9)/18:0, 18:2 (n-6)/20:4 (n-6) and 20:4 (n-6)/18:2 (n-6) are all indicative of the normal activity of enzymes involved in the desaturation and elongation. Thus these studies indicate that addition of cholesterol can modify the fatty acid composition in erythrocytes, kidney and spleen lipids.

Effect of supplementation of milk fat with peanut oil on blood lipids and lipoproteins in infants

Three different groups of infants were fed with different formulae based on milk fat. Group I received cow's milk fat formulae with 20% butter fat whereas groups II and III received a formulae which was supplemented with 50 and 33% of peanut oil supplementation in 20% milk fat respectively. Anthropometric measurements, cholesterol, triglyceride, lipoproteins and plasma fatty acids were followed up to a period of 6 months. The results indicated that cow's milk-fed infants had higher cholesterol levels (P < 0.01) than the other two groups. No significant differences with respect to high-density lipoproteins (HDLs) were found, whereas low-density lipoproteins (LDLs) and very low-density lipoproteins (VLDls (VLDls) were found to be increasing up to a period of 6 months. No significant differences were observed with respect to saturated fatty acids and oleic acid (18:1) levels whereas linoleic acid (18:2) clearly showed a proportional relationship between the intake and plasma levels, indicating a positive correlation. Arachidonic acid (20:4) did not, however, show a proprotionate relationship with respect to linoleic acid (18:2) intake. The triene/tetraene, oleic/linoleic, linoleic/arachidonic and total n6 fatty acids were all normal indicating normal activity of desaturase and elongase enzymes for the optimal utilisation of linoleic acid. Thus, the present study suggests that a vegetable oil such as peanut oil could be used in milk fat to improve the essential fatty acid (EFA) status of infants.

The induction of cytotoxic T cells and tumor regression by soluble antigen formulation

CTLs specific for tumor antigens play a major role in the immunity against cancer. We have shown that class I-restricted CTLs can be induced by injecting soluble antigens mixed in an antigen formulation (AF) that consists of squalane, Tween 80, and Pluronic L121 (S. Raychaudhuri et al., Proc. Natl. Acad. Sci. USA, 89: 8308-8312, 1992). In this study, using ovalbumin and the ovalbumin-expressing transfectoma (EG7) as a tumor model system, we examined the in vivo antitumor effect of antigen-AF mixture. Vaccination of mice with ovalbumin in AF 2 or 3 days after EG7 tumor challenge showed significant inhibition of tumor growth compared to mice vaccinated with ovalbumin in alum or in saline. Depletion of CD8+ cells at the time of immunization completely abrogated the AF-induced tumor protection, indicating that CD8+ T cells are the major effectors in tumor protection in vivo. Depletion of CD4+ cells led to a marginal loss of tumor protection, which may be the result of inhibition of ovalbumin-specific CTL response due to the lack of T-helper activity. Our results demonstrate that AF can be used in subunit vaccines to stimulate CTLs and tumor regression in vivo.

Effect of long term feeding of rice bran oil upon lipids and lipoproteins in rats

The effects of feeding two levels of rice bran oil (RBO) on the growth, lipid parameters, and fatty acid composition of the plasma and liver of rats (Wistar strain) were compared with those produced on animals which had been fed the same levels of peanut oil (PNO). The control animals were fed synthetic diets containing 5 and 20% peanut oil (PNO) and the experimental groups were fed similar diets, containing the same level of rice bran oil (RBO). There was no significant difference with respect to the organ weights between the control and the experimental groups. In general, groups fed 20% oil gained more weight than groups fed 5% oil. The animals which received rice bran oil in their diet had, in general, comparatively lower levels of cholesterol, triglycerides and phospholipids. On the other hand, animals receiving 20% rice bran oil in their diet, showed an increase of 20% in high density lipoproteins (HDL-C), within 18 weeks (p < 0.05), when compared to the animals fed with peanut oil. Similarly, low density lipoprotein cholesterol (LDL-C) and very low density lipoprotein cholesterol (VLDL-C) were lower in RBO-fed groups, than in the PNO-fed groups. There was, however, no significant differences in the cholesterol/phospholipid (C/P) ratio of the two groups. Analysis of plasma and of liver fatty acids indicated, in a general way, the type of fat consumed. There were no significant difference in the P/S ratio, nor any in the oleic/linoleic, oleic/stearic, palmitoleic/palmitic, oleic/palmitic, and oleic/palmitoleic ratios.(ABSTRACT TRUNCATED AT 250 WORDS)

Analysis of B cell repertoire specific to the neutralizing epitopes of glycoprotein 120 in HIV-infected individuals

This study describes the clonotypic analysis of neutralizing anti-gp120 antibodies elicited in HIV-infected individuals by a panel of anti-idiotype monoclonal antibodies (anti-Id MAbs). Sera from 80 HIV-infected individuals at various clinical stages of HIV-infection were tested for reactivity to 19 anti-Id MAbs in ELISA. Anti-idiotype MAbs reacted with between 0 and 26% of sera. Among the 13 idiotypes specific for anti-CD4 site antibodies, 4 were expressed in 15 to 20% of individuals, whereas 2 of 4 idiotypes specific for anti-V3 antibodies were expressed in 15 to 26% of the cases. These data suggest that each HIV-infected individuals has a diverse B cell repertoire to a given neutralizing epitope cluster and that certain clonotypes are more prevalent than others. To correlate the binding activity in ELISA with anti-gp120 specificity, the idiotype-positive antibodies (Id+ Abs) from representative serum samples were isolated by anti-Id MAb-Sepharose affinity columns. In most cases, the epitope specificity and the neutralizing properties of the isolated Id+ Abs correlated with that of anti-gp120 antibodies used for the generation of anti-Id MAbs. We propose that these anti-Id MAbs may be used to identify and measure neutralizing anti-gp120 antibodies of defined specificity in the sera of HIV-infected individuals, HIV-vaccinated individuals, and in HIV-infected mother-infant pairs.

Immunization with a soluble CD4-gp120 complex preferentially induces neutralizing anti-human immunodeficiency virus type 1 antibodies directed to conformation-dependent epitopes of gp120

Preservation of the conformation of recombinant gp120 in an adjuvant, enabling it to elicit conformation-dependent, epitope-specific, broadly neutralizing antibodies, may be critical for the development of any gp120-based human immunodeficiency virus type 1 (HIV-1) vaccine. It was hypothesized that recombinant gp120 complexed with recombinant CD4 could stabilize the conformation-dependent neutralizing epitopes and effectively deliver them to the immune system. Therefore, a soluble CD4-gp120 complex in Syntex adjuvant formulation was tested with mice for its ability to induce neutralizing anti-gp120 antibody responses. Seventeen monoclonal antibodies (MAbs) were generated and characterized. Immunochemical studies, neutralization assays, and mapping studies with gp120 mutants indicated that the 17 MAbs fell into three groups. Four of them were directed to what is probably a conformational epitope involving the C1 domain and did not possess virus-neutralizing activities. Another four MAbs bound to V3 peptide 302-321 and exhibited cross-reactive gp120 binding and relatively weak virus-neutralizing activities. These MAbs were very sensitive to amino acid substitutions, not only in the V3 regions but also in the base of the V1/V2 loop, implying a conformational constraint on the epitope. The last group of nine MAbs recognized conformation-dependent epitopes near the CD4 binding site of gp120 and inhibited the gp120-soluble CD4 interaction. Four of these nine MAbs showed broadly neutralizing activities against multiple laboratory-adapted strains of HIV-1, three of them neutralized only HIVIIIB, and the two lower-affinity MAbs did not neutralize any strain tested. Collectively, the results from this study indicate that immunization with the CD4-gp120 complex can elicit antibodies to conformationally sensitive gp120 epitopes, with some of the antibodies having broadly neutralizing activities. We suggest that immunization with CD4-gp120 complexes may be worth evaluating further for the development of an AIDS vaccine.