Fully human anti-interleukin-8 monoclonal antibodies: potential therapeutics for the treatment of inflammatory disease states

Osteoarthritis: Insights into Diagnosis, Pathophysiology, Therapeutic Avenues, and the Potential of Natural Extracts

Osteoarthritis (OA) stands as a prevalent and progressively debilitating clinical condition globally, impacting joint structures and leading to their gradual deterioration through inflammatory mechanisms. While both non-modifiable and modifiable factors contribute to its onset, numerous aspects of OA pathophysiology remain elusive despite considerable research strides. Presently, diagnosis heavily relies on clinician expertise and meticulous differential diagnosis to exclude other joint-affecting conditions. Therapeutic approaches for OA predominantly focus on patient education for self-management alongside tailored exercise regimens, often complemented by various pharmacological interventions primarily targeting pain alleviation. However, pharmacological treatments typically exhibit short-term efficacy and local and/or systemic side effects, with prosthetic surgery being the ultimate resolution in severe cases. Thus, exploring the potential integration or substitution of conventional drug therapies with natural compounds and extracts emerges as a promising frontier in enhancing OA management. These alternatives offer improved safety profiles and possess the potential to target specific dysregulated pathways implicated in OA pathogenesis, thereby presenting a holistic approach to address the condition's complexities.

Antibody engineering and its therapeutic applications

As a natural function, antibodies defend the host from infected cells and pathogens by recognizing their pathogenic determinants. Antibodies (Abs) gained wide acceptance with an enormous impact on human health and have predominantly captured the arena of bio-therapeutics and bio-diagnostics. The scope of Ab-based biologics is vast, and it is likely to solve many unmet clinical needs in future. The majority of attention is now devoted to developing innovative technologies for manufacturing and engineering Abs, better suited to satisfy human needs. The advent of Ab engineering technologies (AET) led to phenomenal developments leading to the generation of Abs-/Ab-derived molecules with desirable functional properties proportional to their expanding requirements. Evolution brought by AET, from the naturally occurring Ab forms to several advanced Ab formats and derivatives, was much needed as it is of great interest to the pharmaceutical industry. Thus, numerous advancements in AET have propelled success in therapeutic Ab development, along with the potential for ever-increasing improvements. Unique characteristics of Abs, such as its diversity, specificity, structural integrity and an array of possible applications, together inspire continuous innovation in the field. Overall, the AET could assist in conquer of several limitations of Abs in terms of their applicability in the field of therapeutics, diagnostics and research; AET has so far led to the production of next-generation Abs, which have revolutionized these arenas. Here in this review, we discuss the various distinguished engineering platforms for Ab development and the progress in modern therapeutics by the so-called "next-generation Abs."

A Multicenter Phase 2 Randomized Controlled Study on the Efficacy and Safety of Reparixin in the Treatment of Hospitalized Patients with COVID-19 Pneumonia

Introduction

Acute lung injury and acute respiratory distress syndrome are common complications in patients with coronavirus disease 2019 (COVID-19). Poor outcomes in patients with COVID-19 are associated with cytokine release syndrome. Binding of interleukin-8 (CXCL8/IL-8) to its chemokine receptors, CXCR1/2, may mediate this inflammatory process. The aim of this clinical trial was to determine if CXCR1/2 blockade with reparixin can improve clinical outcomes in hospitalized patients with severe COVID-19 pneumonia. The dose and safety of reparixin have been investigated in clinical trials of patients with metastatic breast cancer.

Methods

This was a phase 2, open-label, multicenter, randomized study in hospitalized adult patients with severe COVID-19 pneumonia from May 5, 2020 until November 27, 2020. Patients were randomized 2:1 to receive 1200 mg reparixin orally three times daily or standard of care (SOC) for up to 21 days. The primary endpoint was defined as a composite of clinical events: use of supplemental oxygen, need for mechanical ventilation, intensive care unit admission, and/or use of rescue medication.

Results

Fifty-five patients were enrolled between reparixin (n = 36) and SOC (n = 19). The rate of clinical events was statistically significantly lower in the reparixin group compared with the SOC group (16.7% [95% CI 6.4–32.8%] vs. 42.1% [95% CI 20.3–66.5%], P = 0.02). The sensitivity analysis based on the Cox regression model provided an adjusted hazard ratio of 0.33 with statistical significance lower than 0.05 (95% CI 0.11–0.99; P = 0.047). Reparixin treatment appeared to be well tolerated.

Conclusion

In patients with severe COVID-19, reparixin led to an improvement in clinical outcomes when compared with the SOC. A larger phase 3 clinical study is needed to confirm these results.

Trial Registration

EudraCT identifier, 2020-001645-40; registered May 6, 2020 (retrospectively registered), and clinicaltrials.gov (NCT04794803) on March 8, 2021.

Supplementary Information

The online version contains supplementary material available at 10.1007/s40121-022-00644-6.

Senolytics and senomorphics: Natural and synthetic therapeutics in the treatment of aging and chronic diseases

Cellular senescence is a heterogeneous process guided by genetic, epigenetic and environmental factors, characterizing many types of somatic cells. It has been suggested as an aging hallmark that is believed to contribute to aging and chronic diseases. Senescent cells (SC) exhibit a specific senescence-associated secretory phenotype (SASP), mainly characterized by the production of proinflammatory and matrix-degrading molecules. When SC accumulate, a chronic, systemic, low-grade inflammation, known as inflammaging, is induced. In turn, this chronic immune system activation results in reduced SC clearance thus establishing a vicious circle that fuels inflammaging. SC accumulation represents a causal factor for various age-related pathologies. Targeting of several aging hallmarks has been suggested as a strategy to ameliorate healthspan and possibly lifespan. Consequently, SC and SASP are viewed as potential therapeutic targets either through the selective killing of SC or the selective SASP blockage, through natural or synthetic compounds. These compounds are members of a family of agents called senotherapeutics divided into senolytics and senomorphics. Few of them are already in clinical trials, possibly representing a future treatment of age-related pathologies including diseases such as atherosclerosis, osteoarthritis, osteoporosis, cancer, diabetes, neurodegenerative diseases such as Alzheimer's disease, cardiovascular diseases, hepatic steatosis, chronic obstructive pulmonary disease, idiopathic pulmonary fibrosis and age-related macular degeneration. In this review, we present the already identified senolytics and senomorphics focusing on their redox-sensitive properties. We describe the studies that revealed their effects on cellular senescence and enabled their nomination as novel anti-aging agents. We refer to the senolytics that are already in clinical trials and we present various adverse effects exhibited by senotherapeutics so far. Finally, we discuss aspects of the senotherapeutics that need improvement and we suggest the design of future senotherapeutics to target specific redox-regulated signaling pathways implicated either in the regulation of SASP or in the elimination of SC.

Prospects for COPD treatment

The management of chronic obstructive pulmonary disease (COPD) is fundamentally still heavily dependent on the use of bronchodilators and corticosteroids. Therefore, there is a need for alternative, more effective and safer therapeutic approaches. In particular, since inflammation in COPD lungs is often poorly responsive to corticosteroid treatment, novel pharmacological anti-inflammatory approaches are needed to optimally treat COPD patients. There have been multiple attempts to develop drugs that inhibit recruitment and activation of inflammatory cells, such as macrophages, neutrophils and T-lymphocytes, in the lungs of patients with COPD or target inflammatory mediators that are important in the recruitment or activation of these inflammatory cells or released by such cells. This review article focuses on novel classes of anti-inflammatory drugs that have already been tested in humans as possible treatments for patients with COPD.

Discovery and characterization of a neutralizing pan-ELR+CXC chemokine monoclonal antibody

CXCR1 and CXCR2 signaling play a critical role in neutrophil migration, angiogenesis, and tumorigenesis and are therefore an attractive signaling axis to target in a variety of indications. In human, a total of seven chemokines signal through these receptors and comprise the ELR⁺CXC chemokine family, so named because of the conserved ELRCXC N-terminal motif. To fully antagonize CXCR1 and CXCR2 signaling, an effective therapeutic should block either both receptors or all seven ligands, yet neither approach has been fully realized clinically. In this work, we describe the generation and characterization of LY3041658, a humanized monoclonal antibody that binds and neutralizes all seven human and cynomolgus monkey ELR⁺CXC chemokines and three of five mouse and rat ELR⁺CXC chemokines with high affinity. LY3041658 is able to block ELR⁺CXC chemokine-induced Ca²⁺ mobilization, CXCR2 internalization, and chemotaxis in vitro as well as neutrophil mobilization in vivo without affecting other neutrophil functions. In addition to the in vitro and in vivo activity, we characterized the epitope and structural basis for binding in detail through alanine scanning, crystallography, and mutagenesis. Together, these data provide a robust preclinical characterization of LY3041658 for which the efficacy and safety is being evaluated in human clinical trials for neutrophilic skin diseases.

A C-terminal CXCL8 peptide based on chemokine-glycosaminoglycan interactions reduces neutrophil adhesion and migration during inflammation

Leucocyte recruitment is critical during many acute and chronic inflammatory diseases. Chemokines are key mediators of leucocyte recruitment during the inflammatory response, by signalling through specific chemokine G-protein-coupled receptors (GPCRs). In addition, chemokines interact with cell-surface glycosaminoglycans (GAGs) to generate a chemotactic gradient. The chemokine interleukin-8/CXCL8, a prototypical neutrophil chemoattractant, is characterized by a long, highly positively charged GAG-binding C-terminal region, absent in most other chemokines. To examine whether the CXCL8 C-terminal peptide has a modulatory role in GAG binding during neutrophil recruitment, we synthesized the wild-type CXCL8 C-terminal [CXCL8 (54-72)] (Peptide 1), a peptide with a substitution of glutamic acid (E) 70 with lysine (K) (Peptide 2) to increase positive charge; and also, a scrambled sequence peptide (Peptide 3). Surface plasmon resonance showed that Peptide 1, corresponding to the core CXCL8 GAG-binding region, binds to GAG but Peptide 2 binding was detected at lower concentrations. In the absence of cellular GAG, the peptides did not affect CXCL8-induced calcium signalling or neutrophil chemotaxis along a diffusion gradient, suggesting no effect on GPCR binding. All peptides equally inhibited neutrophil adhesion to endothelial cells under physiological flow conditions. Peptide 2, with its greater positive charge and binding to polyanionic GAG, inhibited CXCL8-induced neutrophil transendothelial migration. Our studies suggest that the E70K CXCL8 peptide, may serve as a lead molecule for further development of therapeutic inhibitors of neutrophil-mediated inflammation based on modulation of chemokine-GAG binding.

Pharmacokinetic comparison of a diverse panel of non-targeting human antibodies as matched IgG1 and IgG2 isotypes in rodents and non-human primates

In this study we compared the pharmacokinetic profile of four unrelated antibodies, which do not bind to mammalian antigens, in IgG1 and IgG2 frameworks in both rats and non-human primates (NHP). This allowed for extensive cross comparison of the impact of antibody isotype, complementarity determining regions (CDR) and model species on pharmacokinetics without the confounding influence of antigen binding in the hosts. While antibody isotype had no significant impact on the pharmacokinetics, the CDRs do alter the profile, and there is an inverse correlation between the neonatal Fc receptor (FcRn) affinity and pharmacokinetic performance. Faster clearance rates were also associated with higher isoelectric points; however, although this panel of antibodies all possess basic isoelectric points, ranging from 8.44 to 9.18, they also have exceptional in vivo half-lives, averaging 369 hours, and low clearance rates, averaging 0.18 ml/h/kg in NHPs. This pattern of pharmacokinetic characteristics was conserved between rats and NHPs.

Identification of differentially expressed genes, associated functional terms pathways, and candidate diagnostic biomarkers in inflammatory bowel diseases by bioinformatics analysis

Inflammatory bowel diseases (IBDs), including ulcerative colitis (UC) and Crohn's disease (CD), are chronic inflammatory disorders caused by genetic influences, the immune system and environmental factors. However, the underlying pathogenesis of IBDs and the pivotal molecular interactions remain to be fully elucidated. The aim of the present study was to identify genetic signatures in patients with IBDs and elucidate the potential molecular mechanisms underlying IBD subtypes. The gene expression profiles of the GSE75214 datasets were obtained from the Gene Expression Omnibus database. Differentially expressed genes (DEGs) were identified in UC and CD patients compared with controls using the GEO2R tool. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analyses of DEGs were performed using DAVID. Furthermore, protein-protein interaction (PPI) networks of the DEGs were constructed using Cytoscape software. Subsequently, significant modules were selected and the hub genes were identified. In the GO and KEGG pathway analysis, the top enriched pathways in UC and CD included Staphylococcus aureus infection, rheumatoid arthritis, complement and coagulation cascades, PI3K/Akt signaling pathway and osteoclast differentiation. In addition, the GO terms in the category biological process significantly enriched by these genes were inflammatory response, immune response, leukocyte migration, cell adhesion, response to molecules of bacterial origin and extracellular matrix (ECM) organization. However, several other biological processes (GO terms) and pathways (e.g., ‘chemotaxis’, ‘collagen catabolic process’ and ‘ECM-receptor interaction’) exhibited significant differences between the two subtypes of IBD. The top 10 hub genes were identified from the PPI network using respective DEGs. Of note, the hub genes G protein subunit gamma 11 (GNG11), G protein subunit beta 4 (GNB4), Angiotensinogen (AGT), Phosphoinositide-3-kinase regulatory subunit 3 (PIK3R3) and C-C motif chemokine receptor 7 (CCR7) are disease-specific and may be used as biomarkers for differentiating UC from CD. Furthermore, module analysis further confirmed that common significant pathways involved in the pathogenesis of IBD subtypes were associated with chemokine-induced inflammation, innate immunity, adapted immunity and infectious microbes. In conclusion, the present study identified DEGs, key target genes, functional pathways and enrichment analysis of IBDs, enhancing the understanding of the pathogenesis of IBDs and also advancing the clarification of the underlying molecular mechanisms of UC and CD. Furthermore, these results may provide potential molecular targets and diagnostic biomarkers for UC and CD.

Underlying Causes and Therapeutic Targeting of the Inflammatory Tumor Microenvironment

Historically, the link between chronic inflammation and cancer has long been speculated. Only more recently, pre-clinical and epidemiologic data as well as clinical evidence all point to the role of the tumor microenvironment as inextricably connected to the neoplastic process. The tumor microenvironment (TME), a complex mix of vasculature, inflammatory cells, and stromal cells is the essential "soil" helping to modulate tumor potential. Increasingly, evidence suggests that chronic inflammation modifies the tumor microenvironment, via a host of mechanisms, including the production of cytokines, pro-inflammatory mediators, angiogenesis, and tissue remodeling. Inflammation can be triggered by a variety of different pressures, such as carcinogen exposure, immune dysfunction, dietary habits, and obesity, as well as genetic alterations leading to oncogene activation or loss of tumor suppressors. In this review, we examine the concept of the tumor microenvironment as related to both extrinsic and intrinsic stimuli that promote chronic inflammation and in turn tumorigenesis. Understanding the common pathways inherent in an inflammatory response and the tumor microenvironment may shed light on new therapies for both primary and metastatic disease. The concept of personalized medicine has pushed the field of oncology to drill down on the genetic changes of a cancer, in the hopes of identifying individually targeted agents. Given the complexities of the tumor microenvironment, it is clear that effective oncologic therapies will necessitate targeting not only the cancer cells, but their dynamic relationship to the tumor microenvironment as well.

Directed evolution of broadly crossreactive chemokine-blocking antibodies efficacious in arthritis

Chemokine receptors typically have multiple ligands. Consequently, treatment with a blocking antibody against a single chemokine is expected to be insufficient for efficacy. Here we show single-chain antibodies can be engineered for broad crossreactivity toward multiple human and mouse proinflammatory ELR⁺ CXC chemokines. The engineered molecules recognize functional epitopes of ELR⁺ CXC chemokines and inhibit neutrophil activation ex vivo. Furthermore, an albumin fusion of the most crossreactive single-chain antibody prevents and reverses inflammation in the K/BxN mouse model of arthritis. Thus, we report an approach for the molecular evolution and selection of broadly crossreactive antibodies towards a family of structurally related, yet sequence-diverse protein targets, with general implications for the development of novel therapeutics.

CXCR2 antagonism has been shown to be anti-arthritic, but anti-chemokine therapies usually fail in the clinic owing to redundancy in chemokine-receptor interactions. Here the authors develop single-chain antibodies with multiple chemokine specificities to achieve high affinity and broad specificity to mouse and human CXC chemokines with efficacy in a K/BxN serum transfer model of arthritis.

Glycosaminoglycan Interactions with Chemokines Add Complexity to a Complex System

Chemokines have two types of interactions that function cooperatively to control cell migration. Chemokine receptors on migrating cells integrate signals initiated upon chemokine binding to promote cell movement. Interactions with glycosaminoglycans (GAGs) localize chemokines on and near cell surfaces and the extracellular matrix to provide direction to the cell movement. The matrix of interacting chemokine–receptor partners has been known for some time, precise signaling and trafficking properties of many chemokine–receptor pairs have been characterized, and recent structural information has revealed atomic level detail on chemokine–receptor recognition and activation. However, precise knowledge of the interactions of chemokines with GAGs has lagged far behind such that a single paradigm of GAG presentation on surfaces is generally applied to all chemokines. This review summarizes accumulating evidence which suggests that there is a great deal of diversity and specificity in these interactions, that GAG interactions help fine-tune the function of chemokines, and that GAGs have other roles in chemokine biology beyond localization and surface presentation. This suggests that chemokine–GAG interactions add complexity to the already complex functions of the receptors and ligands.

Role of neutralizing anti-murine interleukin-17A monoclonal antibody on chronic ozone-induced airway inflammation in mice

Exposure to ozone has led to airway inflammation and airway hyperresponsiveness, which potential mechanisms relate to ozone-induced oxidative stress. IL-17 is a growing target for autoimmune and inflammatory diseases. The aim of the study was to examine the inhibitory effects of anti-murine interleukin-17A monoclonal antibody (IL-17mAb) on adverse effects of ozone which are noted above. After C57/BL6 mice were exposed to ozone (2.5ppm; 3h) for 12 times over 6 weeks, IL-17mAb, PBS was intraperitoneally injected into mice 1h after ozone or air exposure for 6 weeks and mice were studied 24h after final exposure, monitoring bronchial responsiveness, airway inflammatory cells, lung histology, levels of neutrophil-related chemokine and proinflammatory cytokines in bronchoalveolar lavage (BAL) fluid and serum, the expression of IL-17A mRNA and protein, glucocorticoid receptors (GR), and the phosphorylation of p38MAPK in lung tissues. The administration of IL-17mAb reduced the ozone-induced increases in total cells, especially neutrophils; decreased levels of cytokines, including IL-8 in BAL fluid, IL-8 and IL-17A in serum; mitigated the severity of airway hyperresponsiveness; attenuated lung inflammation scores and histologic analysis confirmed the suppression of lung inflammation, compared with the administration of a control PBS. Exposure to ozone results in increases in IL-17A production rate, mRNA and protein levels of IL-17A and the protein level of GR. These effects were halted and reversed by IL-17mAb treatment. Furthermore, IL-17mAb also reduced the phosphorylation of p38MAPK. Therefore, we conclude that IL-17mAb may be a useful therapy in ozone-related diseases, including COPD.

IL-8 Alterations in HIV-1 Infected Children With Disease Progression

Disease progression in HIV-1 infected children is faster than in adults. Less than 5% of the infected children maintain stable CD4 counts beyond 7 years of infection and are termed long-term nonprogressors (LTNPs). Delineating the host immune response in antiretroviral naïve (ART) and treated HIV-1 infected children at different disease stages will help in understanding the immunopathogenesis of the disease.A total of 79 asymptomatic, perinatally HIV-1 infected children (50 ART naïve and 29 ART treated) and 8 seronegative donors were recruited in this study. T- and B-cell activation PCR arrays were performed from the cDNA, using total RNA extracted from the peripheral blood mononuclear cells (PBMCs) of 14 HIV-1 infected children at different stages of the disease. The differentially expressed genes were identified. Quantitative RT-PCR was performed for the (interleukin-8) IL-8 gene and its transcriptional mediators, that is, SHP2, GRB2, and IL-8R (IL-8 receptor/CXCR1). Plasma levels of IL-8 were measured by flow cytometry.Gene array data revealed a higher expression of IL-8 in the ART naïve HIV-1 infected progressors and in ART nonresponders than LTNPs and ART responders, respectively. Quantitative RT-PCR analysis demonstrated a significant higher expression of IL-8 (P < 0.001), its receptor CXCR1 (P = 0.03) and the upstream signaling molecule SHP2 (P = 0.04) in the progressors versus LTNPs. Plasma levels of IL-8 were significantly higher in progressors versus LTNPs (P < 0.001), and ART nonresponders versus ART responders (P < 0.001). A significant negative correlation of plasma levels of IL-8 with CD4 counts (cells/μL) was observed in HIV-1 infected ART naïve subjects (r = -0.488; P < 0.001), while the IL-8 levels positively correlated with viral load in the ART treated children (r = 0.5494; P < 0.001). ART naïve progressors on follow up demonstrated a significant reduction in the mRNA expression (P = 0.05) and plasma levels of IL-8 (P = 0.05) post 6 months of ART initiation suggesting the beneficial role of ART therapy in reducing inflammation in infected children.Our data suggest that IL-8 may serve as a potential prognostic marker in adjunct with CD4 counts to monitor disease progression in the HIV-1 infected children and the efficacy of ART.

Chemokine receptors expression on CD3+ blood cells in bronchial asthma

PURPOSE

Chemokines and their receptors participate in pathomechanism of bronchial asthma. The aim of the study was to analyze the pattern of chemokine receptor expression on T cells in severe asthmatics and to compare to mild-to-moderate patients and controls.

MATERIAL/METHODS

Flow cytometric analysis of CXCR1, CXCR2, CXCR3, CCR3, CCR4, CCR5, CCR7, CCR8 expression on CD3(+)CD8(-) and CD3(+)CD8(+) cells was performed in patients with different severity of chronic asthma and in controls.

RESULTS

Percentages of CD3(+)CD8(+) cells expressing CXCR1 were significantly lower in severe asthmatic than in mild-to-moderate asthmatics and in controls. Percentages of CD3(+)CD8(+) cells expressing CCR7 were significantly lower in the severe asthma group than in control group. Percentages of CD3(+)CD8(-) cells expressing CXCR1, CXCR2 and CCR8 were significantly lower in the severe asthma group than in mild-to-moderate asthmatics and in controls. The number of cells CD3(+)CD8(-) and CD3(+)CD8(+) expressing of CXCR1 was significantly lower in the group of patients using more than 800μg of budesonide daily than in the group of patients using less than 400μg of budesonide. Percentages of CD3(+)CD8(-) cells expressing CXCR3, CCR4 and CCR5 were visibly higher (not significantly) in chronic mild-to-moderate asthma than in healthy controls and severe asthmatics.

CONCLUSIONS

These results may indicate impairment of some chemokine expression on T cells in severe asthma patients. Moreover participation of both chemokine receptors related to Th1 and Th2 responses in mild-to-moderate asthma and attenuation of these responses in severe asthma has been suggested.

PA401, a novel CXCL8-based biologic therapeutic with increased glycosaminoglycan binding, reduces bronchoalveolar lavage neutrophils and systemic inflammatory markers in a murine model of LPS-induced lung inflammation

RATIONALE

Neutrophils play a fundamental role in a number of chronic lung diseases. Among the mediators of their recruitment to the lung, CXCL8 (IL-8) is considered to be one of the major players. CXCL8 exerts its chemotactic activity by binding to its GPCR receptors (CXCR1/R2) located on neutrophils, as well as through interactions with glycosaminoglycans (GAGs) on cell surfaces including those of the microvascular endothelium. Binding to GAG co-receptors is required to generate a solid-phase haptotactic gradient and to present IL-8/CXCL8 in a proper conformation to its receptors on circulating neutrophils.

METHODS

We have engineered increased GAG-binding affinity into human CXCL8, thereby obtaining a competitive inhibitor that displaces wild-type IL-8/CXCL8 from GAGs. By additionally knocking-out the GPCR binding domain of the chemokine, we generated a dominant negative protein (dnCXCL8; PA401) with potent anti-inflammatory characteristics proven in vivo in a murine model of LPS-induced lung inflammation (Adage et al., 2015). Here we have further investigated PA401 activity in this pulmonary model by evaluating plasma changes induced by LPS on white blood cells (WBC) and a broad range of inflammatory markers, especially chemokines, by addressing immediate effects of PA401 on these parameters in healthy and LPS exposed mice.

RESULTS

Aerosolized LPS induced a significant increase in bronchoalveolar lavage (BAL) neutrophils after 3 and 7h, as well as an increase in total WBC and changes in 21 of the 59 measured plasma markers, mostly belonging to the chemokine family. PA401 treatment in saline exposed mice didn't induce major changes in any of the measured parameters. When administered to LPS aerosolized mice, PA401 caused a significant normalization of KC/mCXCL1 and other inflammatory markers, as well as of blood WBC count. In addition, BAL neutrophils were significantly reduced, confirming the previously observed lung anti-inflammatory activity of PA401 in this experiment.

CONCLUSIONS

PA401 is a new promising biologic therapeutic with a novel and unique mechanism of action for interfering with neutrophilic lung inflammation, that also normalizes plasma inflammatory markers.

A fluorescence polarization assay for the experimental validation of an in silico model of the chemokine CXCL8 binding to receptor-derived peptides

Peptide based inhibitors of protein-protein interactions are of great interest in proteomics, structural biology and medicinal chemistry. Optimized inhibitors can be designed by experimental approaches or by computational prediction. Ideally, computational models are adjusted to the peptide-protein complex of interest according to experimental data obtained in specific binding experiments. The chemokine CXCL8 (interleukin-8) is an interesting target for drug discovery due to its role in inflammatory diseases. Given the available structural data and information on its receptor interactions it constitutes a basis for the rational design of inhibitor peptides. Starting from the reported structure of CXCL8 in complex with a peptide derived from its receptor CXCR1 we developed a computational docking procedure to estimate the changes in binding energy as a function of individual amino acid exchanges. This indicates whether the respective amino acid residue must be preserved or can be substituted to maintain or improve affinity, respectively. To validate and improve the assumptions made in this docking simulation we established a fluorescence polarization assay for receptor-derived peptides binding to CXCL8. A peptide library was tested comprising selected mutants characterized by docking simulations. A number of predictions regarding electrostatic interactions were confirmed by these experiments and it was revealed that the model needed to be corrected for backbone flexibility. Therefore, the assay presented here is a promising tool to systematically improve the computational model by iterative cycles of modeling, experimental validation and refinement of the algorithm, leading to a more reliable model and peptides with improved affinity.

Development of monoclonal antibodies in China: overview and prospects

Monoclonal antibodies (mAbs) have become increasingly important as human therapeutic agents. Yet, current research concentrates on technology itself and pays attention to developed countries. This paper aims to provide a comprehensive review of mAbs development in China through systematic analysis of drug registry, patent applications, clinical trials, academic publication, and ongoing R&D projects. The trends in therapeutic areas and industrialization process are also highlighted. Development and research trends of mAbs are analyzed to provide a future perspective of mAbs as therapeutic agents in China.

The effect of the decoy molecule PA401 on CXCL8 levels in bronchoalveolar lavage fluid of patients with cystic fibrosis

BACKGROUND

The chemokine interleukin-8 (CXCL8) is a key mediator of inflammation in airways of patients with cystic fibrosis (CF). Glycosaminoglycans (GAGs) possess the ability to influence the chemokine profile of the CF lung by binding CXCL8 and protecting it from proteolytic degradation. CXCL8 is maintained in an active state by this glycan interaction thus increasing infiltration of immune cells such as neutrophils into the lungs. As the CXCL8-based decoy PA401 displays no chemotactic activity, yet demonstrates glycan binding affinity, the aim of this study was to investigate the anti-inflammatory effect of PA401 on CXCL8 levels, and activity, in CF airway samples in vitro.

METHODS

Bronchoalveolar lavage fluid (BALF) was collected from patients with CF homozygous for the ΔF508 mutation (n=13). CXCL8 in CF BALF pre and post exposure to PA401 was quantified by ELISA. Western blot analysis was used to determine PA401 degradation in CF BALF. The ex vivo chemotactic activity of purified neutrophils in response to CF airway secretions was evaluated post exposure to PA401 by use of a Boyden chamber-based motility assay.

RESULTS

Exposure of CF BALF to increasing concentrations of PA401 (50-1000pg/ml) over a time course of 2-12h in vitro, significantly reduced the level of detectable CXCL8 (P<0.05). Interestingly, PA401 engendered release of CXCL8 from GAGs exposing the chemokine susceptible to proteolysis. Subsequently, a loss of PA401 was observed (P<0.05) due to proteolytic degradation by elastase like proteases. A 25% decrease in neutrophil chemotactic efficiency towards CF BALF samples incubated with PA401 was also observed (P<0.05).

CONCLUSION

PA401 can disrupt CXCL8:GAG complexes, rendering the chemokine susceptible to proteolytic degradation. Clinical application of a CXCL8 decoy, such as PA401, may serve to decrease the inflammatory burden in the CF lung in vivo.

Blockade of proteinase-activated receptor 4 inhibits neutrophil recruitment in experimental inflammation in mice

OBJECTIVE AND DESIGN

The activation of proteinase-activated receptors (PARs) has been implicated in the development of important hallmarks of inflammation, including in vivo leukocyte recruitment; however, its role in the regulation of leukocyte migration in response to inflammatory stimuli has not been elucidated until now. Here, we examined the effects of the PAR4 antagonist YPGKF-NH 2 (tcY-NH2) on neutrophil recruitment in experimentally induced inflammation.

METHODS

BALB/c mice were intrapleurally injected with tcY-NH2 (40 ng/kg) prior to intrapleural injection of carrageenan (Cg) or neutrophil chemoattractant CXCL8; the number of infiltrating neutrophils was evaluated after 4 h, and KC production was assessed at different times after Cg injection. Neutrophil adhesion and rolling cells were studied using a brain circulation preparation 4 h after the Cg or CXCL8 challenge in tcY-NH2-treated mice.

RESULTS

PAR4 blockade inhibited CXCL8- and Cg-induced neutrophil migration into the pleural cavity of BALB/c mice and reduced neutrophil rolling and adherence. Surprisingly, PAR4 blockade increased the level of KC in response to carrageenan.

CONCLUSION

These results demonstrated that PAR4 blockade impairs neutrophil migration in vivo, suggesting that PAR4 plays an important role in the regulation of inflammation, at least in part because of its ability to inhibit the actions of the neutrophil chemoattractant CXCL8.

Novel drug targets for asthma and COPD: lessons learned from in vitro and in vivo models

Asthma and chronic obstructive pulmonary disease (COPD) are highly prevalent respiratory diseases characterized by airway inflammation, airway obstruction and airway hyperresponsiveness. Whilst current therapies, such as β-agonists and glucocorticoids, may be effective at reducing symptoms, they do not reduce disease progression. Thus, there is a need to identify new therapeutic targets. In this review, we summarize the potential of novel targets or tools, including anti-inflammatories, phosphodiesterase inhibitors, kinase inhibitors, transient receptor potential channels, vitamin D and protease inhibitors, for the treatment of asthma and COPD.

Cytokine inhibition in the treatment of COPD

Cytokines play an important part in many pathobiological processes of chronic obstructive pulmonary disease (COPD), including the chronic inflammatory process, emphysema, and altered innate immune response. Proinflammatory cytokines of potential importance include tumor necrosis factor (TNF)-α, interferon-γ, interleukin (IL)-1β, IL-6, IL-17, IL-18, IL-32, and thymic stromal lymphopoietin (TSLP), and growth factors such as transforming growth factor-β. The current objectives of COPD treatment are to reduce symptoms, and to prevent and reduce the number of exacerbations. While current treatments achieve these goals to a certain extent, preventing the decline in lung function is not currently achievable. In addition, reversal of corticosteroid insensitivity and control of the fibrotic process while reducing the emphysematous process could also be controlled by specific cytokines. The abnormal pathobiological process of COPD may contribute to these fundamental characteristics of COPD, and therefore targeting cytokines involved may be a fruitful endeavor. Although there has been much work that has implicated various cytokines as potentially playing an important role in COPD, there have been very few studies that have examined the effect of specific cytokine blockade in COPD. The two largest studies that have been reported in the literature involve the use of blocking antibody to TNFα and CXCL8 (IL-8), and neither has provided benefit. Blocking the actions of CXCL8 through its CXCR2 receptor blockade was not successful either. Studies of antibodies against IL-17, IL-18, IL-1β, and TSLP are currently either being undertaken or planned. There is a need to carefully phenotype COPD and discover good biomarkers of drug efficacy for each specific target. Specific groups of COPD patients should be targeted with specific anticytokine therapy if there is evidence of high expression of that cytokine and there are features of the clinical expression of COPD that will respond.

The osteoblastic and osteoclastic interactions in spinal metastases secondary to prostate cancer

Prostate cancer (PC) is one of the most common cancers arising in men and has a high propensity for bone metastasis, particularly to the spine. At this stage, it often causes severe morbidity due to pathological fracture and/or metastatic epidural spinal cord compression which, if untreated, inevitably leads to intractable pain, neurological deficit, and paralysis. Unfortunately, the underlying molecular mechanisms driving growth of secondary PC in the bony vertebral column remain largely unknown. Further investigation is warranted in order to identify therapeutic targets in the future. This review summarizes the current understanding of PC bone metastasis in the spine, highlighting interactions between key tumor and bone-derived factors which influence tumor progression, especially the functional roles of osteoblasts and osteoclasts in the bone microenvironment through their interactions with metastatic PC cells and the critical pathway RANK/RANKL/OPG in bone destruction.

DAPK2 positively regulates motility of neutrophils and eosinophils in response to intermediary chemoattractants

The tight regulation of granulocyte chemotaxis is crucial for initiation and resolution of inflammation. Here, we show that DAPK2, a Ca(2+)/CaM-sensitive serine/threonine kinase known to modulate cell death in various cell types, is a novel regulator of migration in granulocytes. We demonstrate that human neutrophils and eosinophils express DAPK2 but unlike other leukocytes, no DAPK1 or DAPK3 protein. When DAPK activities were blocked by inhibitors, we found that neither granulocyte lifespan nor phagocytosis was affected. However, such pharmacological inactivation of DAPK activity abolished motility of granulocytes in response to intermediary but not end-target chemoattractants ex vivo. The defect in chemotaxis in DAPK2-inactive granulocytes is likely a result of reduced polarization of the cells, mediated by a lack of MLC phosphorylation, resulting in radial F-actin and pseudopod formation. As neutrophils treated with DAPKi also showed reduced recruitment to the site of inflammation in a mouse peritonitis model, DAPK2 may be a novel target for anti-inflammatory therapies.

Inhibition of human neutrophil activity by an RNA aptamer bound to interleukin-8

Interleukin-8 (IL-8) is a proinflammatory CXC chemokine that has been associated with the promotion of neutrophil chemotaxis, degranulation, and the pathogenesis of several neutrophil-infiltrating chronic inflammatory diseases. In the current study, we generated and characterized a 2'-fluoro-pyrimidine modified RNA aptamer (8A-35) against human IL-8. The 8A-35 aptamer binds to IL-8 with high specificity and affinity, yielding an estimated K(D) of 1.72 pM. NMR data revealed that the residues of Lys8, Leu10, Val63, Val66, Lys69 and Ala74 of IL-8 interact with aptamer. Moreover, the 8A-35 aptamer has a potent IL-8-neutralizing activity that can modulate multiple biological activities of IL-8 in human neutrophils, including migration, intracellular signaling, and intracellular Ca(2+) mobilization. Our results suggest that the 8A-35 aptamer has great potential to be a lead structure in the development of effective therapeutic agents against inflammatory diseases.

Niacin inhibits carrageenan-induced neutrophil migration in mice

Several emerging lines of evidence support an anti-inflammatory role for nicotinic acid (niacin); however, its role in the regulation of leukocyte migration in response to inflammatory stimuli has not been elucidated until now. Herein, we have examined the effect of nicotinic acid on neutrophil recruitment in experimentally induced inflammation. We demonstrated that nicotinic acid treatment inhibited interleukin (IL)-8-induced, leukotriene (LT)B4-induced, and carrageenan-induced neutrophil migration into the pleural cavity of BALB/c mice and reduced neutrophil rolling and adherence in a mouse cremaster muscle preparation. Surprisingly, nicotinic acid treatment increased the level of the neutrophil chemoattractant KC in response to carrageenan. These results suggest that nicotinic acid plays an important role in the regulation of inflammation due to its ability to inhibit the actions of the neutrophil chemoattractants IL-8 and LTB4. Further inhibition of chemoattractants leads to impairment of leukocyte rolling and adherence to the vascular endothelium in the microcirculation of inflamed tissues.

Structure-based design of decoy chemokines as a way to explore the pharmacological potential of glycosaminoglycans

Glycosaminoglycans (GAGs) are a class of highly negatively charged, unbranched, O-linked polysaccharides that are involved in many diseases. Their role as a protein-binding matrix on cell surfaces has long been recognized, but therapeutic approaches to interfere with protein-GAG interactions have been limited due to the complex chemistry of GAGs, on one hand, and due to the lack of specific antibodies against GAGs, on the other hand. We have developed a protein engineering platform (the so-called CellJammer(®) technology), which enables us to introduce higher GAG-binding affinity into wild-type GAG-binding proteins and to combine this with impaired biological, receptor-binding function. Chemokines are among the prototypic GAG-binding proteins and here we present selected results of our CellJammer technology applied to several of these proinflammatory proteins. An overview is given of our lead decoy protein, PA401, which is a CXCL8-based mutant protein with increased GAG-binding affinity and decreased CXCR1/2 binding and activation. Major results from our CCL2 and CCL5 programmes are also summarized and the potential for clinical application of these decoy proteins is presented.

Targeting chemokine receptors in chronic inflammatory diseases: an extensive review

The traffic of the different types of immune cells is an important aspect in the immune response. Chemokines are soluble peptides that are able to attract cells by interaction with chemokine receptors on their target cells. Several different chemokines and receptors exist enabling the specific trafficking of different immune cells. In chronic inflammatory disorders there is abundance of immune cells present at the inflammatory site. This review focuses on the role of chemokine receptors in chronic inflammatory disorders of the lungs, intestine, joints, skin and nervous system and the potential of targeting these receptors as therapeutic intervention in these disorders.

[Limitations of current treatment: unmet needs in the treatment of COPD]

In the last few years, considerable interest has been aroused in the treatment of chronic obstructive pulmonary disease (COPD) and the dearth of therapeutic options has been replaced by a far more proactive treatment approach, reflected in the development of the various guidelines and recommendations of the scientific societies. There are three main steps in the treatment of COPD: prevention of the disease, treatment of its symptoms, progression and complications, and recovery of physical function through respiratory rehabilitation. Considerable advances have been produced in these three dimensions, but limitations have been detected, indicating areas for improvement. The most effective means to prevent the disease is smoking cessation. While there are moderately effective drugs to help individuals quit, no drugs are available to prevent relapses. Moreover, due to health policies, most patients with COPD do not receive drug treatment for smoking. The treatment of COPD and its complications is based on the use of bronchodilators, which improve symptoms and quality of life and, to a greater or lesser extent, prevent exacerbations. However, treatment aimed at the underlying pathogenic causes of the disease, which should be antiinflammatory treatment, remains an unresolved issue due to the discouraging results obtained with inhaled corticosteroids, which should always be used in combination with a bronchodilator. The development of new antiinflammatory agents, such as roflumilast, could improve the management of patients with the most severe disease and repeated exacerbations. Lastly, although respiratory rehabilitation is highly effective in helping patients recover their ability to exercise, few patients have access to this option. As with the treatment of smoking, there is a need to implement respiratory rehabilitation through simple and effective programs and with the support of the health administration.

Contribution of neutrophils to acute lung injury

Treatment of acute lung injury (ALI) and its most severe form, acute respiratory distress syndrome (ARDS), remain unsolved problems of intensive care medicine. ALI/ARDS are characterized by lung edema due to increased permeability of the alveolar-capillary barrier and subsequent impairment of arterial oxygenation. Lung edema, endothelial and epithelial injury are accompanied by an influx of neutrophils into the interstitium and broncheoalveolar space. Hence, activation and recruitment of neutrophils are regarded to play a key role in progression of ALI/ARDS. Neutrophils are the first cells to be recruited to the site of inflammation and have a potent antimicrobial armour that includes oxidants, proteinases and cationic peptides. Under pathological circumstances, however, unregulated release of these microbicidal compounds into the extracellular space paradoxically can damage host tissues. This review focuses on the mechanisms of neutrophil recruitment into the lung and on the contribution of neutrophils to tissue damage in ALI.

Generation of high-affinity fully human anti-interleukin-8 antibodies from its cDNA by two-hybrid screening and affinity maturation in yeast

We have developed a technology for rapidly generating novel and fully human antibodies by simply using the antigen DNA. A human single-chain variable fragment (scFv) antibody library was constructed in a yeast two-hybrid vector with high complexity. After cloning cDNA encoding the mature sequence of human interleukin-8 (hIL8) into the yeast two-hybrid system vector, we have screened the human scFv antibody library and obtained three distinct scFv clones that could specifically bind to hIL8. One clone was chosen for further improvement by a novel affinity maturation process using the error-prone PCR of the scFv sequence followed by additional rounds of yeast two-hybrid screening. The scFv antibodies of both primary and affinity-matured scFv clones were expressed in E. coli. All purified scFvs showed specific binding to hIL8 in reciprocal coimmunoprecipitation and ELISA assays. All scFvs, as well as a fully human IgG antibody converted from one of the scFv clones and expressed in the mammalian cells, were able to effectively inhibit hIL8 in neutrophil chemotaxis assays. The technology described can generate fully human antibodies with high efficiency and low cost.

Application of quantitative pharmacology in development of therapeutic monoclonal antibodies

The advancement of therapeutic monoclonal antibodies during various stages of the drug development process can be effectively streamlined when appropriate translational strategies are applied. Design of successful translational strategies for development of monoclonal antibodies should allow for understanding of the dose- and concentration-response relationships with respect to both beneficial and toxic effects from early phases of drug development. Evaluation of relevant biomarkers during early stages of drug development should facilitate the successful design of safe and effective dosing strategies. Moreover, application of quantitative pharmacology is critical for translation of exposure-response relationships early on.

Anti-chemokine small molecule drugs: a promising future?

IMPORTANCE OF THE FIELD

Chemokines have principally been associated with inflammation due to their role in the control of leukocyte migration, but just over a decade ago chemokine receptors were also identified as playing a pivotal role in the entry of the HIV virus into cells. Chemokines activate seven transmembrane G protein-coupled receptors, making them extremely attractive therapeutic targets for the pharmaceutical industry.

AREAS COVERED IN THIS REVIEW

Although there are now a large number of molecules targeting chemokines and chemokine receptors including neutralizing antibodies in clinical trials for inflammatory diseases, the results to date have not always been positive, which has been disappointing for the field. These failures have often been attributed to redundancy in the chemokine system. However, other difficulties have been encountered in drug discovery processes targeting the chemokine system, and these will be addressed in this review.

WHAT THE READER WILL GAIN

In this review, the reader will get an insight into the hurdles that have to be overcome, learn about some of the pitfalls that may explain the lack of success, and get a glimpse of the outlook for the future.

TAKE HOME MESSAGE

In 2007, the FDA approved maraviroc, an inhibitor of CCR5 for the prevention of HIV infection, the first triumph for a small-molecule drug acting on the chemokine system. The time to market, 11 years from discovery of CCR5, was fast by industry standards. A second small-molecule drug, a CXCR4 antagonist for hematopoietic stem cell mobilization, was approved by the FDA at the end of 2008. The results of a Phase III trial with a CCR9 inhibitor for Crohn's disease are also promising. This could herald the first success for a chemokine receptor antagonist as an anti-inflammatory therapeutic and confirms the importance of chemokine receptors as a target class for anti-inflammatory and autoimmune diseases.

Does activation of the FcgammaRIIa play a role in the pathogenesis of the acute lung injury/acute respiratory distress syndrome?

ALI (acute lung injury) and its more severe form ARDS (acute respiratory distress syndrome) are inflammatory diseases of the lung characterized by hypoxaemia and diffuse bilateral infiltrates. Disruption of epithelial integrity and injury to endothelium are contributing factors of the development of ALI/ARDS, and alveolar damage is the most pronounced feature of ALI/ARDS. The resulting increase in lung microvascular permeability promotes influx of inflammatory cells to the alveolar spaces. Oedema fluid contains pro-nflammatory mediators and plasma proteins, including Igs (immunoglobulins). Moreover, several reports describe the presence of autoantibodies and immune complexes [anti-IL-8 (interleukin-8) autoantibody/IL-8 complexes] in lung fluids (oedema and bronchoalveolar lavage fluids) from patients with ALI/ARDS. These immune complexes associate with FcgammaRIIa (Fcgamma IIa receptor) in lungs of patients with ARDS. Furthermore, the expression of FcgammaRIIa is substantially elevated in lungs of these patients. FcgammaRIIa appears on virtually all myeloid cells, platelets and endothelial cells. It is a low-affinity receptor for IgG that preferentially binds aggregated immunoglobulins and immune complexes. FcgammaRs regulate phagocytosis and cell-mediated cytotoxicity, and initiate the release of inflammatory mediators. It should be noted that immune complexes formed between either anti-neutrophil autoantibodies and their specific antigens or anti-HLA (human leucocyte antigen) antibodies and target antigens are implicated in the pathogenesis of TRALI (transfusion-related acute lung injury), and importantly, animal studies indicate that FcgammaRs are essential for these complexes to cause damage to the lungs. Therefore, we hypothesize that FcgammaRs such as FcgammaRIIa could contribute to the pathogenesis of ALI/ARDS.

Bio-microfluidics: biomaterials and biomimetic designs

Bio-microfluidics applies biomaterials and biologically inspired structural designs (biomimetics) to microfluidic devices. Microfluidics, the techniques for constraining fluids on the micrometer and sub-micrometer scale, offer applications ranging from lab-on-a-chip to optofluidics. Despite this wealth of applications, the design of typical microfluidic devices imparts relatively simple, laminar behavior on fluids and is realized using materials and techniques from silicon planar fabrication. On the other hand, highly complex microfluidic behavior is commonplace in nature, where fluids with nonlinear rheology flow through chaotic vasculature composed from a range of biopolymers. In this Review, the current state of bio-microfluidic materials, designs and applications are examined. Biopolymers enable bio-microfluidic devices with versatile functionalization chemistries, flexibility in fabrication, and biocompatibility in vitro and in vivo. Polymeric materials such as alginate, collagen, chitosan, and silk are being explored as bulk and film materials for bio-microfluidics. Hydrogels offer options for mechanically functional devices for microfluidic systems such as self-regulating valves, microlens arrays and drug release systems, vital for integrated bio-microfluidic devices. These devices including growth factor gradients to study cell responses, blood analysis, biomimetic capillary designs, and blood vessel tissue culture systems, as some recent examples of inroads in the field that should lead the way in a new generation of microfluidic devices for bio-related needs and applications. Perhaps one of the most intriguing directions for the future will be fully implantable microfluidic devices that will also integrate with existing vasculature and slowly degrade to fully recapitulate native tissue structure and function, yet serve critical interim functions, such as tissue maintenance, drug release, mechanical support, and cell delivery.

Chemokines

Tumor growth is restricted to approximately 2 microm diameters by simple dissociation of nutrients and oxygen. Hence, tumors require the formation of new blood vessels for further growth progression. This process is referred to as tumor neo-angiogenesis. The process of tumor neo-angiogenesis is directed by complex bidirectional interactions between the tumor and the vessels, and creates a favorable microenvironment for angiogenesis. The tumor vessel system not only facilitates tumor growth by providing nutrients and oxygen but also functions as a convenient route for metastasis. A group of small cytokine-like molecules called chemokines have been shown to participate in angiogenesis under homeostatic and neoplastic conditions. This review summarizes their role in tumor-associated angiogenesis.

The antigenome: from protein subunit vaccines to antibody treatments of bacterial infections?

New strategies are needed to master infectious diseases. The so-called "passive vaccination", i.e., prevention and treatment with specific antibodies, has a proven record and potential in the management of infections and entered the medical arena more than 100 years ago. Progress in the identification of specific antigens has become the hallmark in the development of novel subunit vaccines that often contain only a single immunogen, frequently proteins, derived from the microbe in order to induce protective immunity. On the other hand, the monoclonal antibody technology has enabled biotechnology to produce antibody species in unlimited quantities and at reasonable costs that are more or less identical to their human counterparts and bind with high affinity to only one specific site of a given antigen. Although, this technology has provided a robust platform for launching novel and successful treatments against a variety of devastating diseases, it is up till now only exceptionally employed in therapy of infectious diseases. Monoclonal antibodies engaged in the treatment of specific cancers seem to work by a dual mode; they mark the cancerous cells for decontamination by the immune system, but also block a function that intervenes with cell growth. The availability of the entire genome sequence of pathogens has strongly facilitated the identification of highly specific protein antigens that are suitable targets for neutralizing antibodies, but also often seem to play an important role in the microbe's life cycle. Thus, the growing repertoire of well-characterized protein antigens will open the perspective to develop monoclonal antibodies against bacterial infections, at least as last resort treatment, when vaccination and antibiotics are no options for prevention or therapy. In the following chapter we describe and compare various technologies regarding the identification of suitable target antigens and the foundation of cognate monoclonal antibodies and discuss their possible applications in the treatment of bacterial infections together with an overview of current efforts.