Locally delivered polyclonal antibodies potentiate intravenous antibiotic efficacy against gram-negative infections

Polyvalent human immunoglobulin for infectious diseases: Potential to circumvent antimicrobial resistance

Antimicrobial resistance (AMR) is a global health problem that causes more than 1.27 million deaths annually; therefore, it is urgent to focus efforts on solving or reducing this problem. The major causes of AMR are the misuse of antibiotics and antimicrobials in agriculture, veterinary medicine, and human medicine, which favors the selection of drug-resistant microbes. One of the strategies proposed to overcome the problem of AMR is to use polyvalent human immunoglobulin or IVIG. The main advantage of this classic form of passive immunization is its capacity to enhance natural immunity mechanisms to eliminate bacteria, viruses, or fungi safely and physiologically. Experimental data suggest that, for some infections, local administration of IVIG may produce better results with a lower dose than intravenous application. This review presents evidence supporting the use of polyvalent human immunoglobulin in AMR, and the potential and challenges associated with its proposed usage.

Expression of TNF, IL1B, and iNOS2 in the neural cell after induced by Porphyromonas gingivalis with and without coating antibody anti -Porphyromonas gingivalis

Porphyromonas gingivalis has virulence factors such as gingipain and lipopolysaccharide, causing bacteremia to reach the brain and activate neuroinflammatory release cytokines. This study analyzed the effect of the co-culture of neuron cells with P. gingivalis coated with anti -P. gingivalis antibodies against cytokines produced by neuron cells. The gene expressions of the TNF, IL1B,  iNOS2 in neurons was evaluated using RT-qPCR. The results showed that P. gingivalis coated with anti -P. gingivalis antibody before co-culture with neuron cells could decrease the gene expression of TNF, IL1B, and  iNOS2 of neuron cells.

Expression of TNF, IL1B, and iNOS2 in the neural cell after induced by Porphyromonas gingivalis with and without coating antibody anti -Porphyromonas gingivalis

Porphyromonas gingivalis has virulence factors such as gingipain and lipopolysaccharide, causing bacteremia to reach the brain and activate neuroinflammatory release cytokines. This study analyzed the effect of the co-culture of neuron cells with P. gingivalis coated with anti -P. gingivalis antibodies against cytokines produced by neuron cells. The gene expressions of the TNF, IL1B,  iNOS2 in neurons was evaluated using RT-qPCR. The results showed that P. gingivalis coated with anti -P. gingivalis antibody before co-culture with neuron cells could decrease the gene expression of TNF, IL1B, and  iNOS2 of neuron cells.

Expression of TNF, IL1B, and NOS2 in the neural cell after induced by Porphyromonas gingivalis with and without coating antibody anti -Porphyromonas gingivalis

Porphyromonas gingivalis has virulence factors such as gingipain and lipopolysaccharide, causing bacteremia to reach the brain and activate neuroinflammatory release cytokines. This study analyzed the effect of the co-culture of neuron cells with P. gingivalis coated with anti -P. gingivalis antibodies against cytokines produced by neuron cells. The gene expressions of the TNF, IL1B, NOS2 in neurons was evaluated using RT-qPCR. The results showed that P. gingivalis coated with anti -P. gingivalis antibody before co-culture with neuron cells could decrease the gene expression of TNF, IL1B, and NOS2 of neuron cells.

Expression of TNF, IL1B, and NOS2 in the neural cell after induced by Porphyromonas gingivalis with and without coating antibody anti -Porphyromonas gingivalis

Porphyromonas gingivalis has virulence factors such as gingipain and lipopolysaccharide, causing bacteremia to reach the brain and activate neuroinflammatory release cytokines. This study analyzed the effect of the co-culture of neuron cells with P. gingivalis coated with anti -P. gingivalis antibodies against cytokines produced by neuron cells. The gene expressions of the TNF, IL1B, NOS2 in neurons was evaluated using RT-qPCR. The results showed that P. gingivalis coated with anti -P. gingivalis antibody before co-culture with neuron cells could decrease the gene expression of TNF, IL1B, and NOS2 of neuron cells.

Development of a sprayable hydrogel formulation for the skin application of therapeutic antibodies

A formulation of an antibody with antibacterial properties for topical use on Staphylococcal skin infections was developed and characterized. The best formulation was obtained with 1.5% (w/v) sodium carboxymethylcellulose containing 10 mg/ml immunoglobulin. Spraying forces and rheological behavior were measured in order to characterize the hydrogel formulation. The percentage of antibody aggregates in gel as well as the antibody release, folding and target binding properties of the released antibody were analyzed to proof an acceptable shelf life and no significant changes in the activity of the antibody over time. No microbial contamination was observed in the chosen non-airless application container. Functional testing of the topical skin formulation was performed with an ex vivo biopsy culture model of dog skin. Histological analysis indicated efficacy in protection from Staphylococcus mediated skin damage and antibody delivery restricted to the epidermal surface. The results demonstrate that this hydrogel is suitable for cutaneous antibody applications in the medical field.

Meropenem versus piperacillin/tazobactam with or without immunoglobulin as second-line therapy for febrile neutropenia in pediatric patients

BACKGROUND

Although survival of children with hematological diseases and cancer has increased dramatically, life-threatening complications due to bacterial infections occur in 5-10% of febrile episodes in pediatric cancer patients. A prospective randomized study was performed to clarify the usefulness of meropenem (MEPM) and piperacillin/tazobactam (PIPC/TAZ) with or without intravenous immunoglobulin (IVIG) as second-line therapy for pediatric patients with febrile neutropenia (FN).

PROCEDURE

As first-line therapy for FN, 105 patients with 434 episodes were randomly assigned to receive MEPM or PIPC/TAZ. A total of 71 pediatric patients and 144 episodes were judged as failures and enrolled for second-line treatment. In second-line treatment, patients were randomized to a group of MEPM and PIPC/TAZ with or without IVIG. MEPM was given to patients who received PIPC/TAZ as first-line treatment, and PIPC/TAZ was given to patients who received MEPM as first-line treatment.

RESULTS

The total success rate of second-line therapy was 49.3%. MEPM with or without IVIG was effective in 44.3% of cases, and PIPC/TAZ with or without IVIG was effective in 55.3%; this difference was not significant. The success rate in patients with serum IgG under 1000 mg/dl was 41.3% in the MEPM or PIPC/TAZ group and 64.3% in the MEPM + IVIG or PIPC/TAZ + IVIG group (p = 0.028).

CONCLUSIONS

The present results suggest that PIPC/TAZ is as effective as MEPM and safe for second-line treatment of FN in pediatric patients. Furthermore, IVIG appears very effective for patients with low serum IgG levels.

A novel combination approach of human polyclonal IVIG and antibiotics against multidrug-resistant Gram-positive bacteria

Background

Gram-positive bacteria, especially methicillin-resistant Staphylococcus aureus (MRSA) and enterococci, have shown a remarkable ability to develop resistance to antimicrobial agents.

Objective

We aimed to assess possible enhancement of the antimicrobial activity of vancomycin, amoxicillin, clarithromycin, and azithromycin by human polyclonal intravenous immunoglobulin G (IVIG) against 34 multidrug-resistant (MDR) bacterial isolates, including MRSA, Enterococcus faecium, and Enterococcus faecalis.

Materials and methods

Double combinations of the antibiotics with the IVIG were assessed by checkerboard assay, where the interaction was evaluated with respect to the minimum inhibitory concentration (MIC) of the antibiotics. The results of the checkerboard assay were verified in vitro using time-kill assay and in vivo using an invasive sepsis murine model.

Results

The checkerboard assay showed that IVIG enhanced the antimicrobial activity of amoxicillin and clarithromycin against isolates from the three groups of bacteria, which were resistant to the same antibiotics when tested in the absence of IVIG. The efficacy of vancomycin against 15% of the tested isolates was enhanced when it was combined with the antibodies. Antagonism was demonstrated in 47% of the E. faecalis isolates when clarithromycin was combined with the IVIG. Synergism was proved in the time-kill assay when amoxicillin was combined with the antibodies; meanwhile, antagonism was not demonstrated in all tested combinations, even in combinations that showed such response in checkerboard assay.

Conclusion

The suggested approach is promising and could be helpful to enhance the antimicrobial activity of not only effective antibiotics but also antibiotics that have been proven to be ineffective against MDR bacteria. To our knowledge, this combinatorial approach against MDR bacteria, such as MRSA and enterococci, has not been investigated before.

Alternative pre-approved and novel therapies for the treatment of anthrax

BACKGROUND

Bacillus anthracis, the causative agent of anthrax, is a spore forming and toxin producing rod-shaped bacterium that is classified as a category A bioterror agent. This pathogenic microbe can be transmitted to both animals and humans. Clinical presentation depends on the route of entry (direct contact, ingestion, injection or aerosolization) with symptoms ranging from isolated skin infections to more severe manifestations such as cardiac or pulmonary shock, meningitis, and death. To date, anthrax is treatable if antibiotics are administered promptly and continued for 60 days. However, if treatment is delayed or administered improperly, the patient's chances of survival are decreased drastically. In addition, antibiotics are ineffective against the harmful anthrax toxins and spores. Therefore, alternative therapeutics are essential. In this review article, we explore and discuss advances that have been made in anthrax therapy with a primary focus on alternative pre-approved and novel antibiotics as well as anti-toxin therapies.

METHODS

A literature search was conducted using the University of Manitoba search engine. Using this search engine allowed access to a greater variety of journals/articles that would have otherwise been restricted for general use. In order to be considered for discussion for this review, all articles must have been published later than 2009.

RESULTS

The alternative pre-approved antibiotics demonstrated high efficacy against B. anthracis both in vitro and in vivo. In addition, the safety profile and clinical pharmacology of these drugs were already known. Compounds that targeted underexploited bacterial processes (DNA replication, RNA synthesis, and cell division) were also very effective in combatting B. anthracis. In addition, these novel compounds prevented bacterial resistance. Targeting B. anthracis virulence, more specifically the anthrax toxins, increased the length of which treatment could be administered.

CONCLUSIONS

Several novel and pre-existing antibiotics, as well as toxin inhibitors, have shown increasing promise. A combination treatment that targets both bacterial growth and toxin production would be ideal and probably necessary for effectively combatting this armed bacterium.

Targeted localized use of therapeutic antibodies: a review of non-systemic, topical and oral applications

Therapeutic antibodies provide important tools in the "medicine chest" of today's clinician for the treatment of a range of disorders. Typically monoclonal or polyclonal antibodies are administered in large doses, either directly or indirectly into the circulation, via a systemic route which is well suited for disseminated ailments. Diseases confined within a specific localized tissue, however, may be treated more effectively and at reduced cost by a delivery system which targets directly the affected area. To explore the advantages of the local administration of antibodies, we reviewed current alternative, non-systemic delivery approaches which are in clinical use, being trialed or developed. These less conventional approaches comprise: (a) local injections, (b) topical and (c) peroral administration routes. Local delivery includes intra-ocular injections into the vitreal humor (i.e. Ranibizumab for age-related macular degeneration), subconjunctival injections (e.g. Bevacizumab for corneal neovascularization), intra-articular joint injections (i.e. anti-TNF alpha antibody for persistent inflammatory monoarthritis) and intratumoral or peritumoral injections (e.g. Ipilimumab for cancer). A range of other strategies, such as the local use of antibacterial antibodies, are also presented. Local injections of antibodies utilize doses which range from 1/10th to 1/100th of the required systemic dose therefore reducing both side-effects and treatment costs. In addition, any therapeutic antibody escaping from the local site of disease into the systemic circulation is immediately diluted within the large blood volume, further lowering the potential for unwanted effects. Needle-free topical application routes become an option when the condition is restricted locally to an external surface. The topical route may potentially be utilized in the form of eye drops for infections or corneal neovascularization or be applied to diseased skin for psoriasis, dermatitis, pyoderma gangrenosum, antibiotic resistant bacterial infections or ulcerated wounds. Diseases confined to the gastrointestinal tract can be targeted directly by applying antibody via the injection-free peroral route. The gastrointestinal tract is unusual in that its natural immuno-tolerant nature ensures the long-term safety of repeatedly ingesting heterologous antiserum or antibody materials. Without the stringent regulatory, purity and clean room requirements of manufacturing parenteral (injectable) antibodies, production costs are minimal, with the potential for more direct low-cost targeting of gastrointestinal diseases, especially with those caused by problematic antibiotic resistant or toxigenic bacteria (e.g. Clostridium difficile, Helicobacter pylori), viruses (e.g. rotavirus, norovirus) or inflammatory bowel disease (e.g. ulcerative colitis, Crohn's disease). Use of the oral route has previously been hindered by excessive antibody digestion within the gastrointestinal tract; however, this limitation may be overcome by intelligently applying one or more strategies (i.e. decoy proteins, masking therapeutic antibody cleavage sites, pH modulation, enzyme inhibition or encapsulation). These aspects are additionally discussed in this review and novel insights also provided. With the development of new applications via local injections, topical and peroral routes, it is envisaged that an extended range of ailments will increasingly fall within the clinical scope of therapeutic antibodies further expanding this market.

Therapeutic strategies to combat antibiotic resistance

With multidrug resistant bacteria on the rise, new antibiotic approaches are required. Although a number of new small molecule antibiotics are currently in the development pipeline with many more in preclinical development, the clinical options and practices for infection control must be expanded. Biologics and non-antibiotic adjuvants offer this opportunity for expansion. Nevertheless, to avoid known mechanisms of resistance, intelligent combination approaches for multiple simultaneous and complimentary therapies must be designed. Combination approaches should extend beyond biologically active molecules to include smart controlled delivery strategies. Infection control must integrate antimicrobial stewardship, new antibiotic molecules, biologics, and delivery strategies into effective combination therapies designed to 1) fight the infection, 2) avoid resistance, and 3) protect the natural microbiome. This review explores these developing strategies in the context of circumventing current mechanisms of resistance.

A Single B-repeat of Staphylococcus epidermidis accumulation-associated protein induces protective immune responses in an experimental biomaterial-associated infection mouse model

Nosocomial infections are the fourth leading cause of morbidity and mortality in the United States, resulting in 2 million infections and ∼100,000 deaths each year. More than 60% of these infections are associated with some type of biomedical device. Staphylococcus epidermidis is a commensal bacterium of the human skin and is the most common nosocomial pathogen infecting implanted medical devices, especially those in the cardiovasculature. S. epidermidis antibiotic resistance and biofilm formation on inert surfaces make these infections hard to treat. Accumulation-associated protein (Aap), a cell wall-anchored protein of S. epidermidis, is considered one of the most important proteins involved in the formation of S. epidermidis biofilm. A small recombinant protein vaccine comprising a single B-repeat domain (Brpt1.0) of S. epidermidis RP62A Aap was developed, and the vaccine's efficacy was evaluated in vitro with a biofilm inhibition assay and in vivo in a murine model of biomaterial-associated infection. A high IgG antibody response against S. epidermidis RP62A was detected in the sera of the mice after two subcutaneous immunizations with Brpt1.0 coadministered with Freund's adjuvant. Sera from Brpt1.0-immunized mice inhibited in vitro S. epidermidis RP62A biofilm formation in a dose-dependent pattern. After receiving two immunizations, each mouse was surgically implanted with a porous scaffold disk containing 5 × 10(6) CFU of S. epidermidis RP62A. Weight changes, inflammatory markers, and histological assay results after challenge with S. epidermidis indicated that the mice immunized with Brpt1.0 exhibited significantly higher resistance to S. epidermidis RP62A implant infection than the control mice. Day 8 postchallenge, there was a significantly lower number of bacteria in scaffold sections and surrounding tissues and a lower residual inflammatory response to the infected scaffold disks for the Brpt1.0-immunized mice than for of the ovalbumin (Ova)-immunized mice.

Assessment of the efficacy of polyclonal intravenous immunoglobulin G (IVIG) against the infectivity of clinical isolates of methicillin-resistant Staphylococcus aureus (MRSA) in vitro and in vivo

The response to treatment of severe methicillin-resistant Staphylococcus aureus (MRSA) infections with the traditional antibiotics is sometimes unsatisfactory and multiple antibiotic resistance is common. Adjuvant therapy such as intravenous immunoglobulin G (IVIG) could possibly be helpful in the treatment of such infections. The effect of IVIG on the capacity of human neutrophils to phagocytose and kill MRSA was investigated in vitro using the MTT assay and measuring the production of reactive oxygen species (ROS) and nitric oxide (NO). The efficiency of IVIG in neutralizing α-hemolysin and coagulase of MRSA was also assessed. The capability of IVIG in the treatment and prevention of MRSA infections was also evaluated in a murine peritonitis model. IVIG significantly enhanced (p < 0.01) the killing of MRSA by neutrophils at all concentrations tested (0.1-5 mg/ml) by 30-80 % of control values. It significantly (p < 0.01) increased the level of NO production in a dose-dependent manner, giving up to 60 μM at 5 mg/ml. The ROS level significantly increased (p < 0.01) in the presence of IVIG. In addition, IVIG significantly reduced the hemolytic activity of MRSA 10-fold and its coagulation capabilities by 50 %. When tested in vivo, groups receiving IVIG via tail vein infusion showed no significant improvement in their survival. Only when delivered to the same site of infection did IVIG show an improvement in the survival of mice (n = 80). These results could pave the way for a better understanding of the mechanism of action of IVIG and suggest its clinical potential as an adjuvant preventive and therapeutic agent against life-threatening infections caused by MRSA and other bacteria.

Antibodies in infectious diseases: polyclonals, monoclonals and niche biotechnology

Antibody preparations have a long history of providing protection from infectious diseases. Although antibodies remain the only natural host-derived defense mechanism capable of completely preventing infection, as products, they compete against inexpensive therapeutics such as antibiotics, small molecule inhibitors and active vaccines. The continued discovery in the monoclonal antibody (mAb) field of leads with broadened cross neutralization of viruses and demonstrable synergy of antibody with antibiotics for bacterial diseases, clearly show that innovation remains. The commercial success of mAbs in chronic disease has not been paralleled in infectious diseases for several reasons. Infectious disease immunotherapeutics are limited in scope as endemic diseases necessitate active vaccine development. Also, the complexity of these small markets draws the interest of niche companies rather than big pharmaceutical corporations. Lastly, the cost of goods for mAb therapeutics is inherently high for infectious agents due to the need for antibody cocktails, which better mimic polyclonal immunoglobulin preparations and prevent antigenic escape. In cases where vaccine or convalescent populations are available, current polyclonal hyperimmune immunoglobulin preparations (pIgG), with modern and highly efficient purification technology and standardized assays for potency, can make economic sense. Recent innovations to broaden the potency of mAb therapies, while reducing cost of production, are discussed herein. On the basis of centuries of effective use of Ab treatments, and with growing immunocompromised populations, the question is not whether antibodies have a bright future for infectious agents, but rather what formats are cost effective and generate safe and efficacious treatments to satisfy regulatory approval.

Prevention of Postoperative Infections in Horses

The best defense against postoperative infection is to use multiple strategies to minimize wound contamination, maintain wound tissue health, and provide rational antimicrobial strategies that do not promote the development of resistant bacteria and superinfections.

Controlled-release and local delivery of therapeutic antibodies

Human and humanised antibodies are now poised to become a major new class of protein-based therapeutic agents. A significant fraction of new drugs in clinical testing (approximately 20% in 2002) are antibody classes. Monoclonal antibodies (mAbs) with high affinities against newly discovered disease targets, both cellularly and extracellularly, are now clinically proven to elicit high bioactivities against numerous diseases, including tumours, infections, asthma, inflammation, arthritis and osteoporosis. Clinical humanised antibody delivery is typically intravenous, with large multiple doses (grams) required for systemic volumes of distribution. Due to the relatively high costs of both this drug type, and its common mode of administration, alternatives are sought where doses might be reduced and the bioavailability and efficacy enhanced. Local, controlled-release methods that deliver antibodies locally to site of disease, offer new possibilities with these potential advantages. However, protein drugs frequently exhibit formulation challenges when packaged in delivery vehicles, and as globular proteins, antibodies are no exception. Several examples of mAb controlled-release and local delivery strategies against several disease targets are reviewed. Importantly, several antibody delivery methods work in tandem with existing clinically-accepted therapeutics, sometimes exhibiting potentiating or synergistic effects in animal models with small molecule, systemically administered drugs.

Delivery systems for small molecule drugs, proteins, and DNA: the neuroscience/biomaterial interface

Manipulation of cellular processes in vivo by the delivery of drugs, proteins or DNA is of paramount importance to neuroscience research. Methods for the presentation of these molecules vary widely, including direct injection (either systemic or stereotactic), osmotic pump-mediated chronic delivery, or even implantation of cells engineered to indefinitely secrete a factor of interest. Biomaterial-based delivery systems represent an alternative to more traditional approaches, with the possibility of increased efficacy. Drug-releasing biomaterials, either as injectable microspheres or as three-dimensional implants, can deliver a molecule of interest (including small molecule drugs, biologically active proteins, or DNA) over a more prolonged period of time than by standard bolus injection, avoiding the need for repeated administration. Furthermore, sustained-release systems can maintain therapeutic concentrations at a target site, thus reducing the chance for toxicity. This review summarizes applications of polymer-based delivery of small molecule drugs, proteins, and DNA specifically relevant to neuroscience research. We detail the fabrication procedures for the polymeric systems and their utility in various experimental models. The biomaterial field offers unique experimental tools with downstream clinical application for the study and treatment of neurologic disease.

Intravenous immunoglobulin for infectious diseases: back to the pre-antibiotic and passive prophylaxis era?

The dramatic increase in both the number of novel infectious agents and resistance to antimicrobial drugs has incited the need for adjunct therapies in the war against infectious diseases. Exciting recent studies have demonstrated the use of antibodies in the form of intravenous immunoglobulin (IVIg) against infections. By virtue of the diverse repertoire of immunoglobulins that possess a wide spectrum of antibacterial and antiviral specificities, IVIg provides antimicrobial efficacy independently of pathogen resistance and represents a promising alternative strategy for the treatment of diseases for which a specific therapy is not yet available.

Treatment of anthrax infection with combination of ciprofloxacin and antibodies to protective antigen of Bacillus anthracis

Currently there is no effective treatment for inhalational anthrax beyond administration of antibiotics shortly after exposure. There is need for new, safe and effective treatments to supplement traditional antibiotic therapy. Our study was based on the premise that simultaneous inhibition of lethal toxin action with antibodies and blocking of bacterial growth by antibiotics will be beneficial for the treatment of anthrax. In this study, we tested the effects of a combination treatment using purified rabbit or sheep anti-protective antigen (PA) antibodies and the antibiotic ciprofloxacin in a rodent anthrax model. In mice infected with a dose of Bacillus anthracis Sterne strain corresponding to 10 LD(50), antibiotic treatment with ciprofloxacin alone only cured 50% of infected animals. Administration of anti-PA IgG in combination with ciprofloxacin produced 90-100% survival. These data indicate that a combination of antibiotic/immunoglobulin therapy is more effective than antibiotic treatment alone in a rodent anthrax model.