Innate TCRβ-chain engagement drives human T cells toward distinct memory-like effector phenotypes with immunotherapeutic potentials

Clonotypic αβ T cell responses to cargoes presented by major histocompatibility complex (MHC), MR1, or CD1 proteins underpin adaptive immunity. Those responses are mostly mediated by complementarity-determining region 3 motifs created by quasi-random T cell receptor (TCR) gene rearrangements, with diversity being highest for TCRγδ. Nonetheless, TCRγδ also displays nonclonotypic innate responsiveness following engagement of germline-encoded Vγ-specific residues by butyrophilin (BTN) or BTN-like (BTNL) proteins that uniquely mediate γδ T cell subset selection. We now report that nonclonotypic TCR engagement likewise induces distinct phenotypes in TCRαβ+ cells. Specifically, antibodies to germline-encoded human TCRVβ motifs consistently activated naïve or memory T cells toward core states distinct from those induced by anti-CD3 or superantigens and from others commonly reported. Those states combined selective proliferation and effector function with activation-induced inhibitory receptors and memory differentiation. Thus, nonclonotypic TCRVβ targeting broadens our perspectives on human T cell response modes and might offer ways to induce clinically beneficial phenotypes in defined T cell subsets.

[Profiling of Targeted miRNAs (8-nt) for the Genes Involved in Type 2 Diabetes Mellitus and Cardiac Hypertrophy]

Type 2 Diabetes Mellitus (T2DM) and cardiac hypertrophy (CH) are among the top ten leading cause of deaths, worldwide. T2DM and cardiac hypertrophy are the chronic diseases, have close association and direct life-threatening complications like stroke, myocardial infarction, retinopathy, nephropathy, and limb amputation. In addition to other medical approaches, miRNAs-based strategy is considered most efficient for early detection of chronic diseases and also has potential for the treatment of T2DM and cardiac hypertrophy like it is being used for cancer in clinical trials. MicroRNAs (miRNAs) are single stranded (non-coding) of 20 to 22 nucleotides sequences which bind to their target mRNA upon the complimentary basis, to silence the protein expression at post transcriptional level. Bioinformatic databases are used like online mendelian inheritance in man (OMIM), gene testing registry (GTR), TargetScan and ShinyGO for validation of disease linked genes and sorting the common miRNAs in both diseases, such as miR-30-5p/101-3p.2/190-5p/506-3p/9-5p/128-3p/137/96-5p/7-5p/107/101-3p.1/98-5p/124-3p.2/124-3p.116-5p/15-5p/497-5p/ 424-5p/195-5p/1271-5p, let-7-5p. Aforementioned databases were also used for the miRNAs which have more than one disease linked genes target in each pathological condition. Such miRNAs for cardiac hypertrophy are: miR-19-3p/183-5p.2/153-3p/372-3p/302-3p/520-3p/373-3p/129-5p/144-3p/139-5p and for T2DM are: miR-27-3p/206/1-3p/181-5p. This finding would be helpful for the appropriate selection of miRNAs and to design applicable research project in future. It will require more validation by using the miRNAs expression analysis, mimic, and anti-miRNA approach to check their potential against cardiac hypertrophy and T2DM.

Development of a refugee health assessment toolkit for specific populations to support primary care

Issue/problem

The United Kingdom (UK) hosts c.136,000 refugees and last year received the most asylum applications in two decades. Despite this, expertise in migrant health is not widespread in general practice, with few comprehensive toolkits available to support crucial initial health assessments of new arrivals.

Description of the problem

A large influx of Afghan refugees entered the UK in autumn 2021. In London, primary care practitioners quickly identified a lack of readily accessible, comprehensive guidance to support them in conducting health assessments for arrivals with a complex range of needs. This was compounded by many in primary care having little or no experience of migrant health.

Results

To address this gap in advice on conducting initial health assessments, a bespoke toolkit was created. The toolkit consolidated advice from a range of partners and resources: the UK Afghan migrant health guide, clinicians with humanitarian experience, front-line practitioners, Doctors of the World, and those leading on the health and public health response. The toolkit ensured greater consistency in the nature and content of assessments, considered not only primary needs but also broader wellbeing, and was responsive to both anticipated and known health priorities.

Lessons

The initial health assessment toolkit for Afghan migrants was well received by frontline staff and has implications for international practice in other areas providing similar health support. The toolkit and associated supporting information has formed a template that can be rapidly adapted to suit emerging needs, as has been done for new arrivals from Ukraine. This work has fed into best practice by the UK National Asylum Steering Group and is to be a case study for a WHO project on country-specific health assessments.

Key messages

• The toolkit is a proof of concept for partnership working towards holistic initial health assessments of new migrants in primary care, bringing together best evidence and pragmatic practice.

• This work has implications for other countries experiencing similar trends in migration and providing health support to an increasing number of new refugees.

Speckle tracking echocardiography in patients with systemic sclerosis: a meta-analysis

Background

Myocardial dysfunction is well established in systemic sclerosis (SSc). The utility of standard echocardiography is limited to detect the onset of myocardial dysfunction. Speckle tracking echocardiography (STE) and strain imaging has emerged as a useful technique to quantify left ventricle hemodynamics and myocardial function in early stages of myocardial dysfunction. We aimed to systematically analyze the existing literature on the application of STE and strain analysis in identifying SSc associated myocardial dysfunction

Methods

PubMed, Cochrane, and Google Scholar were queried for studies from the inception of the databases to 2022. Case control studies that used 2D STE for assessment of strain in SSc patients and controls, were included for the analysis. PRISMA guidelines were followed for selections of studies. Two independent reviewers extracted data. Analysis was done using Cochrane Review Manager 5.0.

Results

Total of 19 studies were included in the analysis that compared strain analysis in SSc patient's vs healthy controls. Of the 16 studies that reported left ventricular (LV) global longitudinal strain, we found significantly lower LV global longitudinal strain in SSc patients (mean difference 1.92; 95% CI 0.98–2.87). Six studies reported LV circumferential strain which was noted to be lower in SSc patients compared to healthy controls (mean difference 3.55; 95% CI 1.60–5.51). Five studies reported LV global radial strain with a similar decrease in radial strain among SSc patients compared to controls (mean difference 4.39; 95% CI −6.95 to −1.83). 10 studies reported right ventricular longitudinal strain with a decrease in longitudinal strain in SSc patient's vs controls (mean difference 2.57; 95% CI 2.03–3.12).

Conclusions

SSc patients have lower strain values compared to controls, which is suggestive of an impaired myocardial function in left and right ventricle. Strain analysis by STE could help with early detection of myocardial dysfunction.

Funding Acknowledgement

Type of funding sources: None.

HIF activation enhances FcγRIIb expression on mononuclear phagocytes impeding tumor targeting antibody immunotherapy

BACKGROUND

Hypoxia is a hallmark of the tumor microenvironment (TME) and in addition to altering metabolism in cancer cells, it transforms tumor-associated stromal cells. Within the tumor stromal cell compartment, tumor-associated macrophages (TAMs) provide potent pro-tumoral support. However, TAMs can also be harnessed to destroy tumor cells by monoclonal antibody (mAb) immunotherapy, through antibody dependent cellular phagocytosis (ADCP). This is mediated via antibody-binding activating Fc gamma receptors (FcγR) and impaired by the single inhibitory FcγR, FcγRIIb.

METHODS

We applied a multi-OMIC approach coupled with in vitro functional assays and murine tumor models to assess the effects of hypoxia inducible factor (HIF) activation on mAb mediated depletion of human and murine cancer cells. For mechanistic assessments, siRNA-mediated gene silencing, Western blotting and chromatin immune precipitation were utilized to assess the impact of identified regulators on FCGR2B gene transcription.

RESULTS

We report that TAMs are FcγRIIbbright relative to healthy tissue counterparts and under hypoxic conditions, mononuclear phagocytes markedly upregulate FcγRIIb. This enhanced FcγRIIb expression is transcriptionally driven through HIFs and Activator protein 1 (AP-1). Importantly, this phenotype reduces the ability of macrophages to eliminate anti-CD20 monoclonal antibody (mAb) opsonized human chronic lymphocytic leukemia cells in vitro and EL4 lymphoma cells in vivo in human FcγRIIb+/+ transgenic mice. Furthermore, post-HIF activation, mAb mediated blockade of FcγRIIb can partially restore phagocytic function in human monocytes.

CONCLUSION

Our findings provide a detailed molecular and cellular basis for hypoxia driven resistance to antitumor mAb immunotherapy, unveiling a hitherto unexplored aspect of the TME. These findings provide a mechanistic rationale for the modulation of FcγRIIb expression or its blockade as a promising strategy to enhance approved and novel mAb immunotherapies.

186 Thyroid Monitoring for Patients Born After the Chernobyl Disaster Within the Blast Radius: A Literature Review

Aim

There is a well-documented increase in incidence of thyroid cancer in individuals living within the blast radius at the time of the Chernobyl nuclear disaster. Following a case encountered in our clinical practice of a patient born within the blast radius but after the blast itself, we aimed to evaluate the evidence of increased thyroid cancer within such a cohort.

Method

We reviewed the existing literature for evidence for or against an increase in thyroid cancer in this population group. Identified articles were reviewed and appraised, evaluating the evidence for any possible increase in incidence.

Results

Very few papers looked at risk in such a population, but those identified suggested no increase in risk of thyroid cancer in individuals born within the radius, after the blast.

Conclusions

We conclude there is little evidence supporting routine monitoring for individuals born within the blast radius after the blast, and as such this should be included in the British Thyroid Association guidelines.

The role of thalidomide in dermatology

Thalidomide is a medication that has been in existence for over half a century, and has proven to be useful and effective in severe dermatological conditions. For dermatologists, the ability of thalidomide to reduce the levels of the cytokine tumour necrosis factor-α, along with its immunomodulatory and anti-angiogenic properties, is of great significance, with the added advantage of being an oral medication. Its use is of course strictly monitored, owing to its potential adverse effects (AEs), particularly teratogenicity, with precautions taken to ensure its safe and correct use by both prescriber and patient. In this review, we look at the background and mechanism of action of thalidomide, provide an overview of conditions it can be used for with case examples, explain the potential AEs and monitoring requirements, and discuss future developments.

1537 Squamous Cell Carcinoma Arising in A Maxillary Odontogenic Keratocyst in Gorlin Goltz Syndrome - A Rare Case Report

Introduction

Gorlin Goltz syndrome (GGS) is a rare, hereditary, AD condition with multiple BCCs, odontogenic keratocysts (Jaw cysts), calcification of falx cerebri, skeletal anomalies & a predisposition to neoplasms like medulloblastomas, fibromas and rhabdomyosarcomas.

Aim

We present a rare case of a Squamous cell carcinoma (SCC) developing in a Maxillary odontogenic keratocyst in a 32-year male with GGS.

Discussion

This patient was referred to the OMFS unit with a non-healing UL3 extraction socket and exophytic growth. Initial biopsies suggested an atypical squamo-proliferative lesion, however a repeat biopsy demonstrated an invasive SCC arising from a background odontogenic keratocyst of the maxilla. He was initially reluctant to undergo a staging CT scan to avoid risks of developing further BCCs due to IR exposure. This was eventually performed as per H&N MDT recommendation & showed a T4aN0M0 SCC of the left maxilla and bilateral multiple mandibular odontogenic keratocysts. He underwent a left maxillectomy, left neck dissection & reconstruction with a DCIA free flap, but did not want his mandibular keratocysts treated at the same time. Complete tumour clearance was achieved with no involved neck nodes & he remains disease-free at 4 months postoperatively. Although for a T4 tumour he would have needed postoperative radiotherapy, in view of the GGS, no adjuvant treatment was indicated.

Conclusions

SCC developing in a maxillary OKC is exceedingly rare with only two previous cases reported in GG syndrome. This is the first reported case of a GGS patient with oral SCC undergoing a complex free flap reconstruction.

Remodeling the Tumor Myeloid Landscape to Enhance Antitumor Antibody Immunotherapies

Among the diverse tumor resident immune cell types, tumor-associated macrophages (TAMs) are often the most abundant, possess an anti-inflammatory phenotype, orchestrate tumor immune evasion and are frequently associated with poor prognosis. However, TAMs can also be harnessed to destroy antibody-opsonized tumor cells through the process of antibody-dependent cellular phagocytosis (ADCP). Clinically important tumor-targeting monoclonal antibodies (mAb) such as Rituximab, Herceptin and Cetuximab, function, at least in part, by inducing macrophages to eliminate tumor cells via ADCP. For IgG mAb, this is mediated by antibody-binding activating Fc gamma receptors (FcγR), with resultant phagocytic activity impacted by the level of co-engagement with the single inhibitory FcγRIIb. Approaches to enhance ADCP in the tumor microenvironment include the repolarization of TAMs to proinflammatory phenotypes or the direct augmentation of ADCP by targeting so-called 'phagocytosis checkpoints'. Here we review the most promising new strategies targeting the cell surface molecules present on TAMs, which include the inhibition of 'don't eat me signals' or targeting immunostimulatory pathways with agonistic mAb and small molecules to augment tumor-targeting mAb immunotherapies and overcome therapeutic resistance.

Effects on egg production and quality of supplementing drinking water with calcium and magnesium

This study was conducted to appraise the effects on egg quality and production performance of laying hens when drinking water was supplemented with calcium (Ca) and magnesium (Mg). A total of 384 (64-week-old) Hy-line Brown laying hens were assigned at random to four treatments, which consisted of CON: unsupplemented drinking water; T1: drinking water + 2 mg/L Ca + 250 mg/L Mg; T2: drinking water + 4 mg/L Ca + 510 mg/L Mg /10 L; and T3: drinking water + 5 mg/L Ca and 760 mg/L Mg. The experiment lasted six weeks. Water intake increased linearly in week 1 with the rising levels of Ca and Mg in the drinking water. Increasing the Ca and Mg levels improved eggshell strength (week 2 (P =0.01), week 5 (P =0.01), and week 6 (P = 0.03), and eggshell thickness (week 6) (P =0.02) and reduced the rate at which eggs were broken (week 4) (P =0.01). The supplemental Ca and Mg did not affect egg production, egg weight, Haugh unit, albumen height, eggshell colour, and yolk colour compared with CON. Nor did they influence the Haugh unit and albumen height after storing for 1, 5, 10 and 15 days. In conclusion, adding Ca and Mg to the drinking water increased the thickness and strength of the eggshells.

Activation of GABA(A) receptors inhibits T cell proliferation

BACKGROUND

The major sites for fast synaptic inhibition in the central nervous system (CNS) are ion channels activated by γ-aminobutyric acid (GABA). These receptors are referred as GABA(A) receptors (GABA(A)R). Recent evidence indicates a role of GABA(A)R in modulating the immune response. This work aimed to discern the role of GABA and GABA(A)Rs in human and mouse T cell activity.

METHODS

Mouse splenocytes or human peripheral blood mononuclear cells (PBMCs) were activated with anti-CD3 antibodies and the proliferation of both CD8+ and CD4+ T cells assessed through flow cytometry. Subsequently, the effects on T cell proliferation of either GABA(A)R modulation by diazepam that is also capable of activating mitochondrial based translocator protein (TSPO), alprazolam and allopregnanolone or inhibition by bicucculine methiodide (BMI) and (1,2,5,6-Tetrahydropyridin-4-yl)methylphosphinic acid (TPMPA) were assessed.

RESULTS

Positive modulation of GABA(A)Rs either by benzodiazepines or the neurosteroid allopregnanolone inhibits both mouse and human T cell proliferation. GABAergic inhibition of T cell proliferation by benzodiazepines could be rescued by GABA(A)R blocking. Our data suggest that benzodiazepines influence T cell proliferation through both TSPO and GABA(A)Rs activation.

CONCLUSIONS

We conclude that activation of GABA(A)Rs provides immunosuppression by inhibiting T cell proliferation.

Merkel cell carcinoma

Merkel cell carcinoma (MCC) of the skin is a rare, aggressive form of skin cancer that metastasizes to other parts of the body. This cutaneous neuroendocrine tumour mainly affects older people, with most cases generally occurring over the age of 50 years. Merkel cell polyomavirus has been shown to induce gene mutations resulting in this skin cancer, with immunosuppression and ultraviolet radiation being other key risk factors in its pathogenesis. MCC is clinically seen as a rapidly enlarging, isolated, irregular erythematous nodule typically found on sun-exposed sites. Diagnosis is through clinical examination followed by tissue biopsy, which demonstrates characteristic histopathological neuroendocrine features. Immunohistochemistry plays a crucial role in diagnosis with the characteristic perinuclear staining with cytokeratin-20 helping to differentiate it from other morphologically similar tumours. Sentinel lymph node biopsy and imaging is essential for staging and determining prognosis. Surgical excision is the mainstay of treatment for localized disease although adjuvant radiotherapy is often required. Metastatic disease involves a very poor prognosis, and immune checkpoint inhibitors have recently shown promise in the treatment of metastatic disease. Avelumab, a monoclonal antibody that binds to the programmed death-1 receptor, has been approved by the National Institute for Health and Care Excellence and shown encouraging survival outcomes. It provides an option for treating metastatic carcinoma in adults after they have failed ≥ 1 line of chemotherapy for metastatic disease.

Domain binding and isotype dictate the activity of anti-human OX40 antibodies

BACKGROUND

Previous data suggests that anti-OX40 mAb can elicit anti-tumor effects in mice through deletion of Tregs. However, OX40 also has powerful costimulatory effects on T cells which could evoke therapeutic responses. Human trials with anti-OX40 antibodies have shown that these entities are well tolerated but to date have delivered disappointing clinical responses, indicating that the rules for the optimal use of anti-human OX40 (hOX40) antibodies is not yet fully understood. Changes to timing and dosages may lead to improved outcomes; however, here we focus on addressing the role of agonism versus depleting activity in determining therapeutic outcomes. We investigated a novel panel of anti-hOX40 mAb to understand how these reagents and mechanisms may be optimized for therapeutic benefit.

METHODS

This study examines the binding activity and in vitro activity of a panel of anti-hOX40 antibodies. They were further evaluated in several in vivo models to address how isotype and epitope determine mechanism of action and efficacy of anti-hOX40 mAb.

RESULTS

Binding analysis revealed the antibodies to be high affinity, with epitopes spanning all four cysteine-rich domains of the OX40 extracellular domain. In vivo analysis showed that their activities relate directly to two key properties: (1) isotype-with mIgG1 mAb evoking receptor agonism and CD8+ T-cell expansion and mIgG2a mAb evoking deletion of Treg and (2) epitope-with membrane-proximal mAb delivering more powerful agonism. Intriguingly, both isotypes acted therapeutically in tumor models by engaging these different mechanisms.

CONCLUSION

These findings highlight the significant impact of isotype and epitope on the modulation of anti-hOX40 mAb therapy, and indicate that CD8+ T-cell expansion or Treg depletion might be preferred according to the composition of different tumors. As many of the current clinical trials using OX40 antibodies are now using combination therapies, this understanding of how to manipulate therapeutic activity will be vital in directing new combinations that are more likely to improve efficacy and clinical outcomes.

Impact of Human FcγR Gene Polymorphisms on IgG-Triggered Cytokine Release: Critical Importance of Cell Assay Format

Monoclonal antibody (mAb) immunotherapy has transformed the treatment of allergy, autoimmunity, and cancer. The interaction of mAb with Fc gamma receptors (FcγR) is often critical for efficacy. The genes encoding the low-affinity FcγR have single nucleotide polymorphisms (SNPs) and copy number variation that can impact IgG Fc:FcγR interactions. Leukocyte-based in vitro assays remain one of the industry standards for determining mAb efficacy and predicting adverse responses in patients. Here we addressed the impact of FcγR genetics on immune cell responses in these assays and investigated the importance of assay format. FcγR genotyping of 271 healthy donors was performed using a Multiplex Ligation-Dependent Probe Amplification assay. Freeze-thawed/pre-cultured peripheral blood mononuclear cells (PBMCs) and whole blood samples from donors were stimulated with reagents spanning different mAb functional classes to evaluate the association of FcγR genotypes with T-cell proliferation and cytokine release. Using freeze-thawed/pre-cultured PBMCs, agonistic T-cell-targeting mAb induced T-cell proliferation and the highest levels of cytokine release, with lower but measurable responses from mAb which directly require FcγR-mediated cellular effects for function. Effects were consistent for individual donors over time, however, no significant associations with FcγR genotypes were observed using this assay format. In contrast, significantly elevated IFN-γ release was associated with the FCGR2A-131H/H genotype compared to FCGR2A-131R/R in whole blood stimulated with Campath (p ≤ 0.01) and IgG1 Fc hexamer (p ≤ 0.05). Donors homozygous for both the high affinity FCGR2A-131H and FCGR3A-158V alleles mounted stronger IFN-γ responses to Campath (p ≤ 0.05) and IgG1 Fc Hexamer (p ≤ 0.05) compared to donors homozygous for the low affinity alleles. Analysis revealed significant reductions in the proportion of CD14hi monocytes, CD56dim NK cells (p ≤ 0.05) and FcγRIIIa expression (p ≤ 0.05), in donor-matched freeze-thawed PBMC compared to whole blood samples, likely explaining the difference in association between FcγR genotype and mAb-mediated cytokine release in the different assay formats. These findings highlight the significant impact of FCGR2A and FCGR3A SNPs on mAb function and the importance of using fresh whole blood assays when evaluating their association with mAb-mediated cytokine release in vitro. This knowledge can better inform on the utility of in vitro assays for the prediction of mAb therapy outcome in patients.

Bacterial count and predisposing factors of Clostridium perfringens (targeting CPA gene) infection along with antimicrobial sensitivity in diarrheic sheep in Pakistan

Clostridium perfringens (C. perfringens) is a normal inhabitant in the gut of animals. It may proliferate rapidly in favorable conditions and produces lethal toxins. These toxins may cause lethal effects in the intestines and systemically it may cause enterotoxaemia. In disease conditions, the presence of C. perfringens CFU/g in fecal sample can be of diagnostic value. This study aims to determine the bacterial counts and predisposing factors of C. perfringens (targeting CPA gene) infection in addition to an in-vitro antimicrobial trial in entero-toxemic sheep in Pakistan. A total of 192 diarrheic sheep irrespective of age, gender and breed were selected and the CFU/g was determined from the fecal samples. The study showed that 34.9% of the samples had elevated level of bacterial count compared to the normal (10⁴-10⁷ CFU/g). Out of the total, 7.8% of the samples had subnormal bacterial count (CFU/g), while, 57.3% of the samples showed bacterial counts in the normal ranges. The confirmation of selectively isolated C. perfringens was done by amplification of 324bp CPA gene fragment using polymerase chain reaction (PCR). The in-vitro antimicrobial sensitivity trials showed that penicillin, ciprofloxacin and ceftriaxone are 100% efficacious against C. perfringens, while, bacitracin, ampicillin and amoxicillin were found to be least effective. The key determinants in this study which support the in-vivo growths of C. perfringens were; carbohydrate rich diet and overcrowding with the odds ratios (OR) of 5.44 and 2.26, respectively. This study concludes that C. perfringens is highly prevalent in sheep population of Pakistan. The incidence of enterotoxaemia can be minimized by controlling the factors which enhance its in-vivo growth. The diseased animal associated with elevated C. perfringens levels can be effectively cured using any one of the penicillin, ciprofloxacin and ceftriaxone.

Enteroinsular hormones in two siblings with Donohue syndrome and complete leptin deficiency

The main biochemical hallmark of the rare and lethal condition of Donohue syndrome (DS) is hyperinsulinemia. The roles of the gut and other pancreatic hormones involved in glucose metabolism, satiety and energy expenditure have not been previously reported in DS. Two siblings with genetically confirmed DS and extremely low weight underwent a mixed meal (MM) test where pancreatic hormones insulin, C-peptide, glucagon, active amylin, pancreatic polypeptide (PP) as well as gut hormones active glucagon-like peptide 1 (GLP-1), glucose-dependent insulinotropic peptide (GIP), ghrelin, peptide YY (PYY) and leptin were analyzed using a Multiplex assay. Results were compared to those of 2 pediatric controls. As expected, concentrations of insulin, C-peptide and amylin were very high in DS cases. The serum glucagon concentration was undetectable at the time of hypoglycemia. GIPs concentrations were lower in the DS, however, this was not mimicked by the other incretin, GLP-1. Ghrelin concentrations were mainly undetectable (<13.7 pg/mL) in all participants. DS cases had higher PYY and dampened PP concentrations. Leptin levels remained completely undetectable (<137.0 pg/mL). Patients with DS have extremely high amylin levels, completely undetectable serum glucagon and leptin levels with abnormal satiety regulating hormone PP with a relatively normal ghrelin response during a MM test. The low serum GIP might be acting as physiological brake on insulin secretion. The undetectable serum leptin levels suggest the potential of using leptin analogues as therapy for DS patients.

Antibody Tumor Targeting Is Enhanced by CD27 Agonists through Myeloid Recruitment

Monoclonal antibodies (mAbs) can destroy tumors by recruiting effectors such as myeloid cells, or targeting immunomodulatory receptors to promote cytotoxic T cell responses. Here, we examined the therapeutic potential of combining a direct tumor-targeting mAb, anti-CD20, with an extended panel of immunomodulatory mAbs. Only the anti-CD27/CD20 combination provided cures. This was apparent in multiple lymphoma models, including huCD27 transgenic mice using the anti-huCD27, varlilumab. Detailed mechanistic analysis using single-cell RNA sequencing demonstrated that anti-CD27 stimulated CD8+ T and natural killer cells to release myeloid chemo-attractants and interferon gamma, to elicit myeloid infiltration and macrophage activation. This study demonstrates the therapeutic advantage of using an immunomodulatory mAb to regulate lymphoid cells, which then recruit and activate myeloid cells for enhanced killing of mAb-opsonized tumors.

An exploratory, open-label, randomized, multicenter study to investigate the pharmacodynamics of a glycoengineered antibody (imgatuzumab) and cetuximab in patients with operable head and neck squamous cell carcinoma

BACKGROUND

In addition to inhibiting epidermal growth factor receptor (EGFR) signaling, anti-EGFR antibodies of the IgG1 'subtype' can induce a complementary therapeutic effect through the induction of antibody-dependent cell-mediated cytotoxicity (ADCC). Glycoengineering of therapeutic antibodies increases the affinity for the Fc-gamma receptor, thereby enhancing ADCC.

PATIENTS AND METHODS

We investigated the changes in immune effector cells and EGFR pathway biomarkers in 44 patients with operable, advanced stage head and neck squamous cell carcinoma treated with two preoperative doses of either glycoengineered imgatuzumab (GA201; 700 or 1400 mg) or cetuximab (standard dosing) in a neoadjuvant setting with paired pre- and post-treatment tumor biopsies.

RESULTS

Significant antitumor activity was observed with both antibodies after just two infusions. Metabolic responses were seen in 23 (59.0%) patients overall. One imgatuzumab-treated patient (700 mg) achieved a 'pathological' complete response. An immediate and sustained decrease in peripheral natural killer cells was consistently observed with the first imgatuzumab infusion but not with cetuximab. The functionality of the remaining peripheral natural killer cells was maintained. Similarly, a pronounced increase in circulating cytokines was seen following the first infusion of imgatuzumab but not cetuximab. Overall, tumor-infiltrating CD3+ cell counts increased following treatment with both antibodies. A significant increase from baseline in CD3+/perforin+ cytotoxic T cells occurred only in the 700-mg imgatuzumab group (median 95% increase, P < 0.05). The most prominent decrease of EGFR-expressing cells was recorded after treatment with imgatuzumab (700 mg, -34.6%; 1400 mg, -41.8%). The post-treatment inflammatory tumor microenvironment was strongly related to baseline tumor-infiltrating immune cell density, and baseline levels of EGFR and pERK in tumor cells most strongly predicted therapeutic response.

CONCLUSIONS

These pharmacodynamic observations and relationship with efficacy are consistent with the proposed mode of action of imgatuzumab combining efficient EGFR pathway inhibition with ADCC-related immune antitumor effects.

CLINICAL TRIAL REGISTRATION NUMBER

NCT01046266 (ClinicalTrials.gov).

Genetic barcoding and phylogenetic analysis of dusky cotton bug (Oxycarenus hyalinipennis) using mitochondrial cytochrome c oxidase I gene

Cotton dusky bug (Oxycarenus spp.) mostly attack on cash crops such as Gossypium, Cola and Hibiscus which affect the national economy therefore sustainable pest management is needed. Cytochrome c oxidase I (COI) gene is utilized as marker gene for DNA barcoding, genetic and ecological study of insects. In present study insect (cotton dusky bug) samples were collected from cotton fields in Faisalabad. COI gene was amplified from genomic DNA of bug and cloned into pTZ57R/T vector (Fermentas). The clone was sent to Macrogen (South Korea) for Sanger sequencing. The phylogenetic analysis and pairwise multiple sequence alignment showed that our cotton dusky bug grouped with two species of Oxycarenus genus and highest sequence identity was 91.1% with Oxycarenus hylinipennis. This is the first report of genetic barcode of Oxycarenus hylinipennis from cotton from Pakistan.

STING Activation Reverses Lymphoma-Mediated Resistance to Antibody Immunotherapy

Tumors routinely attract and co-opt macrophages to promote their growth, angiogenesis, and metastasis. Macrophages are also the key effector cell for mAb therapies. Here we report that the tumor microenvironment creates an immunosuppressive signature on tumor-associated macrophages (TAM), which favors expression of inhibitory rather than activating Fcγ receptors (FcγR), thereby limiting the efficacy of mAb immunotherapy. We assessed a panel of TLR and STING agonists (a) for their ability to reprogram macrophages to a state optimal for mAb immunotherapy. Both STINGa and TLRa induced cytokine release, modulated FcγR expression, and augmented mAb-mediated tumor cell phagocytosis in vitro However, only STINGa reversed the suppressive FcγR profile in vivo, providing strong adjuvant effects to anti-CD20 mAb in murine models of lymphoma. Potent adjuvants like STINGa, which can improve FcγR activatory:inhibitory (A:I) ratios on TAM, are appealing candidates to reprogram TAM and curb tumor-mediated immunosuppression, thereby empowering mAb efficacy. Cancer Res; 77(13); 3619-31. ©2017 AACR.

A CACNA1D mutation in a patient with persistent hyperinsulinaemic hypoglycaemia, heart defects, and severe hypotonia

Congenital hyperinsulinaemic hypoglycaemia (HH) can occur in isolation or it may present as part of a wider syndrome. For approximately 40%-50% of individuals with this condition, sequence analysis of the known HH genes identifies a causative mutation. Identifying the underlying genetic aetiology in the remaining cases is important as a genetic diagnosis will inform on recurrence risk, may guide medical management and will provide valuable insights into β-cell physiology. We sequenced the exome of a child with persistent diazoxide-responsive HH, mild aortic insufficiency, severe hypotonia, and developmental delay as well as the unaffected parents. This analysis identified a de novo mutation, p.G403D, in the proband's CACNA1D gene. CACNA1D encodes the main L-type voltage-gated calcium channel in the pancreatic β-cell, a key component of the insulin secretion pathway. The p.G403D mutation had been reported previously as an activating mutation in an individual with primary hyper-aldosteronism, neuromuscular abnormalities, and transient hypoglycaemia. Sequence analysis of the CACNA1D gene in 60 further cases with HH did not identify a pathogenic mutation. Identification of an activating CACNA1D mutation in a second patient with congenital HH confirms the aetiological role of CACNA1D mutations in this disorder. A genetic diagnosis is important as treatment with a calcium channel blocker may be an option for the medical management of this patient.

Helicobacter pylori-Mediated Protection from Allergy Is Associated with IL-10-Secreting Peripheral Blood Regulatory T Cells

Helicobacter pylori infections are usually established in early childhood and continuously stimulate immunity, including T-helper 1 (Th1), Th17, and regulatory T-cell (Treg) responses, throughout life. Although known to be the major cause of peptic ulcer disease and gastric cancer, disease occurs in a minority of those who are infected. Recently, there has been much interest in beneficial effects arising from infection with this pathogen. Published data robustly show that the infection is protective against asthma in mouse models. Epidemiological studies show that H. pylori is inversely associated with human allergy and asthma, but there is a paucity of mechanistic data to explain this. Since Th1 and Treg responses are reported to protect against allergic responses, we investigated if there were links between the human systemic Th1 and Treg response to H. pylori and allergen-specific IgE levels. The human cytokine and T-cell responses were examined using peripheral blood mononuclear cells (PBMCs) from 49 infected and 58 uninfected adult patients. Concentrations of total and allergen-specific plasma IgE were determined by ELISA and ImmunoCAP assays. These responses were analyzed according to major virulence factor genotypes of the patients' colonizing H. pylori strains. An in vitro assay was employed, using PBMCs from infected and uninfected donors, to determine the role of Treg cytokines in the suppression of IgE. Significantly higher frequencies of IL-10-secreting CD4(+)CD25(hi) Tregs, but not H. pylori-specific Th1 cells, were present in the peripheral blood of infected patients. Total and allergen-specific IgE concentrations were lower when there was a strong Treg response, and blocking IL-10 in vitro dramatically restored IgE responses. IgE concentrations were also significantly lower when patients were infected with CagA(+) strains or those expressing the more active i1 form of VacA. The systemic IL-10(+) Treg response is therefore likely to play a role in H. pylori-mediated protection against allergy in humans.

Development of new UV-vis spectroscopic microwave-assisted method for determination of glucose in pharmaceutical samples

A new UV-Visible spectroscopic method assisted with microwave for the determination of glucose in pharmaceutical formulations was developed. In this study glucose solutions were oxidized by ammonium molybdate in the presence of microwave energy and reacted with aniline to produce a colored solution. Optimum conditions of the reaction including wavelength, temperature, and pH of the medium and relative concentration ratio of the reactants were investigated. It was found that the optimal wavelength for the reaction is 610 nm, the optimal reaction time is 80s, the optimal reaction temperature is 160°C, the optimal reaction pH is 4, and the optimal concentration ratio aniline/ammonium molybdate solution was found to be 1:1. The limits of detection and quantification of the method are 0.82 and 2.75 ppm for glucose solution, respectively. The use of microwaves improved the speed of the method while the use of aniline improved the sensitivity of the method by shifting the wavelength.

Development and Characterization of Monoclonal Antibodies Specific for Mouse and Human Fcγ Receptors

FcγRs are key regulators of the immune response, capable of binding to the Fc portion of IgG Abs and manipulating the behavior of numerous cell types. Through a variety of receptors, isoforms, and cellular expression patterns, they are able to fine-tune and direct appropriate responses. Furthermore, they are key determinants of mAb immunotherapy, with mAb isotype and FcγR interaction governing therapeutic efficacy. Critical to understanding the biology of this complex family of receptors are reagents that are robust and highly specific for each receptor. In this study, we describe the development and characterization of mAb panels specific for both mouse and human FcγR for use in flow cytometry, immunofluorescence, and immunocytochemistry. We highlight key differences in expression between the two species and also patterns of expression that will likely impact on immunotherapeutic efficacy and translation of therapeutic agents from mouse to clinic.

Evaluation of High-Throughput Genomic Assays for the Fc Gamma Receptor Locus

Cancer immunotherapy has been revolutionised by the use monoclonal antibodies (mAb) that function through their interaction with Fc gamma receptors (FcγRs). The low-affinity FcγR genes are highly homologous, map to a complex locus at 1p23 and harbour single nucleotide polymorphisms (SNPs) and copy number variation (CNV) that can impact on receptor function and response to therapeutic mAbs. This complexity can hinder accurate characterisation of the locus. We therefore evaluated and optimised a suite of assays for the genomic analysis of the FcγR locus amenable to peripheral blood mononuclear cells and formalin-fixed paraffin-embedded (FFPE) material that can be employed in a high-throughput manner. Assessment of TaqMan genotyping for FCGR2A-131H/R, FCGR3A-158F/V and FCGR2B-232I/T SNPs demonstrated the need for additional methods to discriminate genotypes for the FCGR3A-158F/V and FCGR2B-232I/T SNPs due to sequence homology and CNV in the region. A multiplex ligation-dependent probe amplification assay provided high quality SNP and CNV data in PBMC cases, but there was greater data variability in FFPE material in a manner that was predicted by the BIOMED-2 multiplex PCR protocol. In conclusion, we have evaluated a suite of assays for the genomic analysis of the FcγR locus that are scalable for application in large clinical trials of mAb therapy. These assays will ultimately help establish the importance of FcγR genetics in predicting response to antibody therapeutics.

Equilibrative nucleoside transporter 3 depletion in β-cells impairs mitochondrial function and promotes apoptosis: Relationship to pigmented hypertrichotic dermatosis with insulin-dependent diabetes

Loss of function recessive mutations in the SLC29A3 gene that encodes human equilibrative nucleoside transporter 3 (ENT3) have been identified in patients with pigmented hypertrichotic dermatosis with insulin-dependent diabetes (PHID). ENT3 is a member of the equilibrative nucleoside transporter (ENT) family whose primary function is mediating transport of nucleosides and nucleobases. The aims of this study were to characterise ENT3 expression in islet β-cells and identify the effects of its depletion on β-cell mitochondrial activity and apoptosis. RT-PCR amplification identified ENT3 expression in human and mouse islets and exocrine pancreas, and in MIN6 β-cells. Immunohistochemistry using human and mouse pancreas sections exhibited extensive ENT3 immunostaining of β-cells, which was confirmed by co-staining with an anti-insulin antibody. In addition, exposure of dispersed human islet cells and MIN6 β-cells to MitoTracker and an ENT3 antibody showed co-localisation of ENT3 to β-cell mitochondria. Consistent with this, Western blot analysis confirmed enhanced ENT3 immunoreactivity in β-cell mitochondria-enriched fractions. Furthermore, ENT3 depletion in β-cells increased mitochondrial DNA content and promoted an energy crisis characterised by enhanced ATP-linked respiration and proton leak. Finally, inhibition of ENT3 activity by dypridamole and depletion of ENT3 by siRNA-induced knockdown resulted in increased caspase 3/7 activities in β-cells. These observations demonstrate that ENT3 is predominantly expressed by islet β-cells where it co-localises with mitochondria. Depletion of ENT3 causes mitochondrial dysfunction which is associated with enhanced β-cell apoptosis. Thus, apoptotic loss of islet β-cells may contribute to the occurrence of autoantibody-negative insulin-dependent diabetes in individuals with non-functional ENT3 mutations.

Antagonistic human FcγRIIB (CD32B) antibodies have anti-tumor activity and overcome resistance to antibody therapy in vivo

Therapeutic antibodies have transformed cancer therapy, unlocking mechanisms of action by engaging the immune system. Unfortunately, cures rarely occur and patients display intrinsic or acquired resistance. Here, we demonstrate the therapeutic potential of targeting human (h) FcγRIIB (CD32B), a receptor implicated in immune cell desensitization and tumor cell resistance. FcγRIIB-blocking antibodies prevented internalization of the CD20-specific antibody rituximab, thereby maximizing cell surface accessibility and immune effector cell mediated antitumor activity. In hFcγRIIB-transgenic (Tg) mice, FcγRIIB-blocking antibodies effectively deleted target cells in combination with rituximab, and other therapeutic antibodies, from resistance-prone stromal compartments. Similar efficacy was seen in primary human tumor xenografts, including with cells from patients with relapsed/refractory disease. These data support the further development of hFcγRIIB antibodies for clinical assessment.

Helicobacter pylori infection reduces disease severity in an experimental model of multiple sclerosis

Recent research has demonstrated that infection with the bacterial pathogen Helicobacter pylori is less common amongst patients with multiple sclerosis (MS), an inflammatory demyelinating disease of the central nervous system (CNS). We aimed to compare the prevalence of H. pylori amongst MS patients and healthy controls, and also investigated the impact of this infection on an animal model for MS, experimental autoimmune encephalomyelitis (EAE). The H. pylori status of 71 MS patients and 42 healthy controls was determined by serology. Groups of C57BL/6 mice were infected with H. pylori, or given diluent alone as a placebo, prior to inducing EAE. Clinical scores were assessed for all mice, and spleens and spinal cord tissue were harvested. CD4⁺ T cell subsets were quantified by flow cytometry, and T cell proliferation assays were performed. In MS patients the seroprevalence of H. pylori was half that of healthy controls (p = 0.018). Over three independent experiments, prior H. pylori infection had a moderate effect in reducing the severity of EAE (p = 0.012). In line with this, the antigen-specific T cell proliferative responses of infected animals were significantly reduced (p = 0.001), and there was a fourfold reduction in the number of CD4⁺ cells in the CNS. CD4⁺ populations in both the CNS and the spleens of infected mice also contained greatly reduced proportions of IFNγ⁺, IL-17⁺, T-bet⁺, and RORγt⁺ cells, but the proportions of Foxp3⁺ cells were equivalent. There were no differences in the frequency of splenic CD4⁺cells expressing markers of apoptosis between infected and uninfected animals. H. pylori was less prevalent amongst MS patients. In mice, the infection exerted some protection against EAE, inhibiting both Th1 and Th17 responses. This could not be explained by the presence of increased numbers of Foxp3⁺ regulatory T cells, or T cell apoptosis. This is the first direct experimental evidence showing that H. pylori may provide protection against inflammatory demyelination in the CNS.

Upregulation of FcγRIIb on monocytes is necessary to promote the superagonist activity of TGN1412

The anti-CD28 superagonist antibody TGN1412 caused life-threatening cytokine release syndrome (CRS) in healthy volunteers, which had not been predicted by preclinical testing. T cells in fresh peripheral blood mononuclear cells (PBMCs) do not respond to soluble TGN1412 but do respond following high-density (HD) preculture. We show for the first time that this response is dependent on crystallizable fragment gamma receptor IIb (FcγRIIb) expression on monocytes. This was unexpected because, unlike B cells, circulating monocytes express little or no FcγRIIb. However, FcγRIIb expression is logarithmically increased on monocytes during HD preculture, and this upregulation is necessary and sufficient to explain TGN1412 potency after HD preculture. B-cell FcγRIIb expression is unchanged by HD preculture, but B cells can support TGN1412-mediated T-cell proliferation when added at a frequency higher than that in PBMCs. Although low-density (LD) precultured PBMCs do not respond to TGN1412, T cells from LD preculture are fully responsive when cocultured with FcγRIIb-expressing monocytes from HD preculture, which shows that they are fully able to respond to TGN1412-mediated activation. Our novel findings demonstrate that cross-linking by FcγRIIb is critical for the superagonist activity of TGN1412 after HD preculture, and this may contribute to CRS in humans because of the close association of FcγRIIb-bearing cells with T cells in lymphoid tissues.