Protein A Suppresses Immune Responses during Staphylococcus aureus Bloodstream Infection in Guinea Pigs

ABSTRACT Staphylococcus aureusinfection is not associated with the development of protective immunity, and disease relapses occur frequently. We hypothesize that protein A, a factor that binds immunoglobulin Fcγ and cross-links VH3 clan B cell receptors (IgM), is the staphylococcal determinant for host immune suppression. To test this, vertebrate IgM was examined for protein A cross-linking. High VH3 binding activity occurred with human and guinea immunoglobulin, whereas mouse and rabbit immunoglobulins displayed little and no binding, respectively. Establishing a guinea pig model of S. aureus bloodstream infection, we show that protein A functions as a virulence determinant and suppresses host B cell responses. Immunization with SpAKKAA, which cannot bind immunoglobulin, elicits neutralizing antibodies that enable guinea pigs to develop protective immunity.IMPORTANCE Staphylococcus aureusis the leading cause of soft tissue and bloodstream infections; however, a vaccine with clinical efficacy is not available. Using mice to model staphylococcal infection, earlier work identified protective antigens; however, corresponding human clinical trials did not reach their endpoints. We show that B cell receptor (IgM) cross-linking by protein A is an important immune evasion strategy of S. aureus that can be monitored in a guinea pig model of bloodstream infection. Further, immunization with nontoxigenic protein A enables infected guinea pigs to elicit antibody responses that are protective against S. aureus. Thus, the guinea pig model may support preclinical development of staphylococcal vaccines.

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Efficacy of the Investigational Echinocandin ASP9726 in a Guinea Pig Model of Invasive Pulmonary Aspergillosis

Antimicrobial Agents and Chemotherapy ◽

10.1128/aac.04857-14 ◽

2015 ◽

Vol 59 (5) ◽

pp. 2875-2881 ◽

Cited By ~ 9

Author(s):

Nathan P. Wiederhold ◽

Laura K. Najvar ◽

Satoru Matsumoto ◽

Rosie A. Bocanegra ◽

Monica L. Herrera ◽

...

Keyword(s):

Guinea Pig ◽

Quantitative Pcr ◽

Guinea Pigs ◽

Plasma Concentrations ◽

Invasive Pulmonary Aspergillosis ◽

Pig Model ◽

Pulmonary Aspergillosis ◽

Content Type ◽

Fungal Burden ◽

Guinea Pig Model

ABSTRACTASP9726 is an investigational echinocandin within vitroactivity againstAspergillusspecies. We evaluated the pharmacokinetics and efficacy of this agent in an established guinea pig model of invasive pulmonary aspergillosis. ASP9726 plasma concentrations were measured in guinea pigs administered either a single dose or multiple doses of this agent at 2.5, 5, and 10 mg/kg of body weight/day by subcutaneous injection. Immunosuppressed guinea pigs were inoculated withA. fumigatusAF293, and ASP9726 (2.5, 5, and 10 mg/kg/day), voriconazole (10 mg/kg by oral gavage twice daily), or caspofungin (3 mg/kg/day by intraperitoneal injection) was administered for 8 days. Changes in fungal burden were measured by enumerating CFU and by quantitative PCR of specimens from within the lungs, as well as by analysis of serum (1→3)-β-d-glucan and galactomannan. Lung histopathology was also evaluated. ASP9726 plasma concentrations increased in a dose-proportional manner, and the drug was well tolerated at each dose. Each dose of ASP9726, voriconazole, and caspofungin significantly reduced pulmonary fungal burden as measured by quantitative PCR and by determining (1→3)-β-d-glucan and galactomannan levels, but only voriconazole significantly reduced numbers of CFU. ASP9726 at 5 mg/kg also significantly improved survival. Histopathology demonstrated morphological changes in hyphae in animals exposed to ASP9726 and caspofungin, consistent with the activities of the echinocandins. These results suggest that ASP9726 may be efficacious for the treatment of invasive pulmonary aspergillosis.

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Rifapentine Is Not More Active than Rifampin against Chronic Tuberculosis in Guinea Pigs

Antimicrobial Agents and Chemotherapy ◽

10.1128/aac.00500-12 ◽

2012 ◽

Vol 56 (7) ◽

pp. 3726-3731 ◽

Cited By ~ 27

Author(s):

Noton K. Dutta ◽

Peter B. Illei ◽

Charles A. Peloquin ◽

Michael L. Pinn ◽

Khisimuzi E. Mdluli ◽

...

Keyword(s):

Guinea Pig ◽

Guinea Pigs ◽

Current Treatment ◽

Active Tuberculosis ◽

Pig Model ◽

Intracellular Accumulation ◽

Duration Of Treatment ◽

Content Type ◽

Guinea Pig Model ◽

Culture Positive

ABSTRACTRifamycins are key sterilizing drugs in the current treatment of active tuberculosis (TB). Daily dosing of rifapentine (P), a potent rifamycin with high intracellular accumulation, in place of rifampin (R) in the standard antitubercular regimen significantly shortens the duration of treatment needed to prevent relapse in a murine model of active TB. We undertook the current study to compare directly the activities of human-equivalent doses of P and R in a guinea pig model of chronic TB, in which bacilli are predominantly extracellular within human-like necrotic granulomas. Hartley strain guinea pigs were aerosol infected with ∼200 bacilli ofMycobacterium tuberculosisH37Rv, and treatment given 5 days/week was initiated 6 weeks later. R at 100 mg/kg of body weight and P at 100 mg/kg were given orally alone or in combination with isoniazid (H) at 60 mg/kg and pyrazinamide (Z) at 300 mg/kg. Culture-positive relapse was assessed in subgroups of guinea pigs after completion of 1 and 2 months of treatment. Human-equivalent doses of R and P showed equivalent bactericidal activity when used alone and in combination therapy. In guinea pigs treated with rifampin, isoniazid, and pyrazinamide (RHZ) or PHZ, microbiological relapse occurred in the lungs of 8/10 animals treated for 1 month and in 0/10 animals treated for 2 months. Substitution of P for R in the standard antitubercular regimen did not shorten the time to cure in this guinea pig model of chronic TB. Data from ongoing clinical trials comparing the activity of these two drugs are awaited to determine the relevance of the guinea pig TB model in preclinical drug screening.

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Listeriosis in the Pregnant Guinea Pig: a Model of Vertical Transmission

Infection and Immunity ◽

10.1128/iai.72.1.489-497.2004 ◽

2004 ◽

Vol 72 (1) ◽

pp. 489-497 ◽

Cited By ~ 95

Author(s):

Anna I. Bakardjiev ◽

Brian A. Stacy ◽

Susan J. Fisher ◽

Daniel A. Portnoy

Keyword(s):

Guinea Pig ◽

Vertical Transmission ◽

Guinea Pigs ◽

Effective Means ◽

Clinical Manifestations ◽

Pig Model ◽

Cellular Mechanisms ◽

Guinea Pig Model ◽

Internalin A

ABSTRACT Feto-placental infections represent a major cause of pregnancy complications, and yet the underlying molecular and cellular mechanisms of vertical transmission are poorly understood. Listeria monocytogenes, a facultative intracellular pathogen, is one of a group of pathogens that are known to cause feto-placental infections in humans and other mammals. The purpose of this study was to evaluate possible mechanisms of vertical transmission of L. monocytogenes. Humans and guinea pigs have a hemochorial placenta, where a single layer of fetally derived trophoblasts separates maternal from fetal circulation. We characterized L. monocytogenes infection of the feto-placental unit in a pregnant guinea pig model and in primary human trophoblasts and trophoblast-derived cell lines. The clinical manifestations of listeriosis in the pregnant guinea pigs and the tropism of L. monocytogenes to the guinea pig placenta resembled those in humans. Trophoblast cell culture systems were permissive for listerial growth and cell-to-cell spread and revealed that L. monocytogenes deficient in internalin A, a virulence factor that mediates invasion of nonphagocytic cells, was 100-fold defective in invasion. However, crossing of the feto-placental barrier in the guinea pig model was independent of internalin A, suggesting a negligible role for internalin-mediated direct invasion of trophoblasts in vivo. Further understanding of vertical transmission of L. monocytogenes will help in designing more effective means of treatment and disease prevention.

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Iron Does Not Cause Arrhythmias in the Guinea Pig Model of Transfusional Iron Overload.

Blood ◽

10.1182/blood.v108.11.3724.3724 ◽

2006 ◽

Vol 108 (11) ◽

pp. 3724-3724

Author(s):

Lana Kaiser ◽

John Davis ◽

Jon Patterson ◽

N. Bari Olivier ◽

George Bohart ◽

...

Keyword(s):

Guinea Pig ◽

Iron Overload ◽

Cardiac Arrhythmias ◽

Guinea Pigs ◽

Pig Model ◽

Cardiac Events ◽

Liver Iron ◽

Secondary Iron Overload ◽

Life Threatening ◽

Guinea Pig Model

Abstract Cardiac events, including heart failure and arrhythmias, are the major cause of death in patients with b-thalassemia. Although cardiac arrhythmias in humans are believed to result from iron overload, excluding confounding factors in the human population is difficult. The purpose of these studies was to evaluate the development of cardiac arrhythmias using the guinea pig model of secondary iron overload. Electrocardiograms were recorded via surgically implanted telemetry devices in guinea pigs loaded intraperitoneally with iron dextran and controls. Cardiac and liver iron concentrations were significantly elevated in the iron loaded animals when compared to control, and were in the range of those reported for humans with thalassemia. Arrhythmias were noted infrequently in both iron loaded and control guinea pigs. No life threatening arrhythmias were detected in either group. These data suggest that iron alone may be insufficient to cause cardiac arrhythmias, and that arrhythmias detected in individuals with iron overload may be the result of a complex interplay of factors.

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Staphylococcus aureus Protein A Promotes Immune Suppression

mBio ◽

10.1128/mbio.00764-13 ◽

2013 ◽

Vol 4 (5) ◽

Cited By ~ 34

Author(s):

Scott D. Kobayashi ◽

Frank R. DeLeo

Keyword(s):

Staphylococcus Aureus ◽

B Cell ◽

Immune Evasion ◽

Bacterial Infections ◽

Binding Capacity ◽

Protein A ◽

Strong Support ◽

The United States ◽

Content Type

ABSTRACTStaphylococcus aureusis a prominent cause of human infections worldwide and is notorious for its ability to acquire resistance to antibiotics. Methicillin-resistantS. aureus(MRSA), in particular, is endemic in hospitals and is the most frequent cause of community-associated bacterial infections in the United States. Inasmuch as treatment options for severe MRSA infections are limited, there is need for a vaccine that protects against such infections. However, recent efforts to generate a staphylococcal vaccine have met with little success in human clinical trials. These failures are somewhat puzzling, since the vaccine antigens tested promote opsonophagocytosisin vitroand confer protection in animal infection models. One possibility is that the pathogen inhibits (and/or fails to elicit) the development of protective immunity in humans. Indeed,S. aureusproduces numerous molecules that can potentially promote immune evasion, including protein A (SpA), an immunoglobulin (Ig)-binding protein present on the bacterial surface and freely secreted into the extracellular environment. SpA binds the Fc region of antibody and the Fab regions of the B-cell receptor, processes that are known to block opsonophagocytosis and cause B-cell deathin vitro. In a recent study, Falugi et al. [F. Falugi, H. K. Kim, D. M. Missiakas, and O. Schneewind, mBio 4(5):e00575-13, 2013] showed that vaccination withspamutantS. aureusstrains lacking antibody Fc- and/or Fab-binding capacity protects against subsequent challenge with the USA300 epidemic strain. The findings provide strong support for the idea that SpA promotesS. aureusimmune evasionin vivoand form the foundation for a new approach in our efforts to develop a vaccine that prevents severeS. aureusinfections.

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Protein A-Specific Monoclonal Antibodies and Prevention of Staphylococcus aureus Disease in Mice

Infection and Immunity ◽

10.1128/iai.00230-12 ◽

2012 ◽

Vol 80 (10) ◽

pp. 3460-3470 ◽

Cited By ~ 56

Author(s):

Hwan Keun Kim ◽

Carla Emolo ◽

Andrea C. DeDent ◽

Fabiana Falugi ◽

Dominique M. Missiakas ◽

...

Keyword(s):

Staphylococcus Aureus ◽

Monoclonal Antibodies ◽

Immune Responses ◽

B Cell ◽

Protein A ◽

Abscess Formation ◽

Staphylococcal Protein A ◽

Content Type ◽

Humoral Immune ◽

Binding Domains

ABSTRACTStaphylococcus aureusis a leading cause of human soft tissue infections and bacterial sepsis. The emergence of antibiotic-resistant strains (methicillin-resistantS. aureus[MRSA]) has prompted research into staphylococcal vaccines and preventive measures. The envelope ofS. aureusis decorated with staphylococcal protein A (SpA), which captures the Fcγ portion of immunoglobulins to prevent opsonophagocytosis and associates with the Fab portion of VH3-type B cell receptors to trigger B cell superantigen activity. Nontoxigenic protein A (SpAKKAA), when used as an immunogen in mice, stimulates humoral immune responses that neutralize the Fcγ and the VH3+Fab binding activities of SpA and provide protection from staphylococcal abscess formation in mice. Here, we isolated monoclonal antibodies (MAbs) against SpAKKAAthat, by binding to the triple-helical bundle fold of its immunoglobulin binding domains (IgBDs), neutralize the Fcγ and Fab binding activities of SpA. SpAKKAAMAbs promoted opsonophagocytic killing of MRSA in mouse and human blood, provided protection from abscess formation, and stimulated pathogen-specific immune responses in a mouse model of staphylococcal disease. Thus, SpAKKAAMAbs may be useful for the prevention and therapy of staphylococcal disease in humans.

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The ascorbate-deficient guinea pig model of shigellosis allows the study of the entire Shigella life cycle

10.1101/2020.08.28.270074 ◽

2020 ◽

Author(s):

Antonin C André ◽

Céline Mulet ◽

Mark C Anderson ◽

Louise Injarabian ◽

Achim Buch ◽

...

Keyword(s):

Animal Model ◽

Life Cycle ◽

Guinea Pig ◽

Guinea Pigs ◽

Colonic Mucosa ◽

Extended Period ◽

Pig Model ◽

Suitable Animal Model ◽

Guinea Pig Model

AbstractShigella spp. are the causative agents of bacillary dysentery or shigellosis, mainly in children living in developing countries. The study of Shigella entire life cycle in vivo and the evaluation of vaccine candidates’ protection efficacy have been hampered by the lack of a suitable animal model of infection (1). None of the ones evaluated so far (mouse, rabbit, guinea pig) allows to recapitulate shigellosis symptoms upon Shigella oral challenge. Historical reports suggest that dysentery and scurvy are both metabolic diseases associated with ascorbate-deficiency. Mammals which are susceptible to Shigella infection (humans, non-human primates and guinea pigs) are the lonely ones which are unable to synthesize ascorbate. We optimized a low-ascorbate diet to induce moderate ascorbate-deficiency but not scurvy in guinea pigs (Ascplasma conc.=1.6 μM vs 36 μM with optimal ascorbate supply). We demonstrated that moderate ascorbate-deficiency increases shigellosis severity during extended period of time (up to 48h) with all strains tested (Shigella flexneri 5a and 2a, Shigella sonnei). At late time-points, a massive influx of neutrophils was observed both within the disrupted colonic mucosa and in the luminal compartment, although Shigella remains able to disseminate deep into the organ to reach the sub-mucosal layer and the bloodstream. This new model of shigellosis opens new doors for the study both of Shigella infection strategy and innate and adaptive immune responses to Shigella infection. It may be also of a great interest to study the virulence of other pathogen for which no suitable animal model of infection is available (Vibrio cholerae, Yersinia pestis, Mycobacterium tuberculosis or Campylobacter jejuni, among others).SignificanceThe study of Shigella virulence cycle in vivo has been hampered by the lack of a suitable animal model, which would allow the colonic mucosa infection upon oral challenge. Based on historical reports and physiological aspects, it was suggested that ascorbate-deficiency may stand as a new dysentery risk-factor. To test this hypothesis, we set up a new ascorbate-deficient guinea pig model and demonstrated for the first time that the Shigella infectious process occurred for extended period of time (up to 48h) and demonstrated that shigellosis severity was higher in ascorbate-deficient animal. Ascorbate-deficient guinea pig model of infection may be used to assess the virulence of other pathogens for which no suitable animal model of infection is still lacking.

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The Novel TRPA1 Antagonist BI01305834 Inhibits Ovalbumin-Induced Bronchoconstriction in Guinea Pigs

10.21203/rs.3.rs-88800/v1 ◽

2020 ◽

Author(s):

Mariska van den Berg ◽

Susan Nijboer - Brinksma ◽

Sophie Bos ◽

Maarten van den Berge ◽

David Lamb ◽

...

Keyword(s):

Pilot Study ◽

Guinea Pig ◽

Guinea Pigs ◽

Ex Vivo ◽

Optimal Dose ◽

Pig Model ◽

The Novel ◽

Airway Narrowing ◽

Guinea Pig Model

Abstract Background: We hypothesized that TRPA1 channels contribute to airway hyperresponsiveness (AHR) and inflammation in asthma. We evaluated the efficacy of the novel TRPA1 antagonist BI01305834 in a guinea pig model of asthma. Methods: First a pilot study was performed in a guinea pig model of allergic asthma to find the optimal dose of BI01305834. Next, the effect of BI01305834 on AHR to inhaled histamine after the early and late asthmatic reaction (EAR and LAR), magnitude of EAR and LAR and airway inflammation was assessed. Precision-cut lung slices and trachea strips were used to investigate the bronchoprotective and bronchodilating effect of BI01305834. Statistical evaluation of differences of in vivo data was performed using a Mann-Whitney U test or One-way nonparametric Kruskal-Wallis ANOVA, for ex vivo data One- or Two-way ANOVA was used, all with Dunnett’s post-hoc test where appropriate.Results: A dose of 1 mg/kg BI01305834 was selected based on AHR and exposure data in blood samples from the pilot study. In the subsequent study 1 mg/kg BI01305834 inhibited AHR after the EAR, and the development of EAR and LAR elicited by ovalbumin in ovalbumin-sensitized guinea pigs. BI01305834 did not inhibit allergen-induced total and differential cells in the lavage fluid and interleukin-13 gene expression in lung homogenates. Furthermore, BI01305834 was able to inhibit allergen and histamine-induced airway narrowing in guinea pig lung slices, without affecting histamine release, and reverse allergen-induced bronchoconstriction in guinea pig trachea strips.Conclusions: TRPA1 inhibition protects against AHR and the EAR and LAR in vivo and allergen and histamine-induced airway narrowing ex vivo, and reverses allergen-induced bronchoconstriction, independently of inflammation. This effect was partially dependent upon histamine, suggesting a neuronal and possible non-neuronal role for TRPA1 in allergen-induced bronchoconstriction.

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A new candidate vaccine for human brucellosis based on influenza viral vectors: development of immunization schedule in guinea pig model

10.21203/rs.3.rs-56762/v3 ◽

2020 ◽

Author(s):

Dina Bugybayeva ◽

Zhailaubay Kydyrbayev ◽

Nadezhda Zinina ◽

Nurika Assanzhanova ◽

Bolat Yespembetov ◽

...

Keyword(s):

Guinea Pig ◽

Guinea Pigs ◽

Viral Vectors ◽

Virulent Strain ◽

Pig Model ◽

Effective Vaccine ◽

Human Brucellosis ◽

Sublingual Administration ◽

Vector Vaccine ◽

Guinea Pig Model

Abstract Background: A new candidate vector vaccine against human brucellosis based on recombinant influenza viral vectors (rIVV) subtypes H5N1 expressing Brucella Omp16, L7/L12, Omp19 or Cu-Zn SOD proteins has been developed. This paper presents the results of the study of protection of the vaccine with various options of administering, dosing and frequency of use on guinea pigs.Methods: General states of guinea pigs was assessed based on , behavior and dynamics of a guinea pig weight-gain test. The effectiveness of the new anti-brucellosis vector vaccine was determined by studying its protective effect after conjunctival, intranasal and sublingual administration in doses 105 EID50, 106 EID50 and 107 EID50 during prime and boost vaccinations of animals, followed by challenge with a virulent strain of B. mellitensis 16M infection. For sake of comparison, the commercial B. melitensis Rev.1 vaccine was used as a control. The protective properties of vaccines were assessed by quantitation of Brucella colonization in organs and tissues of infected animals and compared to the control groups.Results: It was observed a gradual increase in body weight of guinea pigs after prime and booster immunization with the vaccine using conjunctival, intranasal and sublingual routes of administration, as well as after using various doses of vaccine. . The most optimal way of using the vaccine has been established: double intranasal immunization of guinea pigs at a dose of 106 EID50, which provides 80% protection of guinea pigs from B. melitensis 16M infection (P < 0.05), which is comparable to the results of the effectiveness of the commercial B. melitensis Rev.1 vaccine.Conclusions: We developed effective vaccine candidate against brucellosis and developed its immunization protocol in guinea pig model. We believe that this study is a substantial step for using the vaccine for future pre-clinical and clinical trials in human.

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A new candidate vaccine for human brucellosis based on influenza viral vectors: development of immunization schedule in guinea pig model

10.21203/rs.3.rs-56762/v2 ◽

2020 ◽

Author(s):

Dina Bugybayeva ◽

Zhailaubay Kydyrbayev ◽

Nadezhda Zinina ◽

Nurika Assanzhanova ◽

Bolat Yespembetov ◽

...

Keyword(s):

Guinea Pig ◽

Guinea Pigs ◽

Viral Vectors ◽

Pig Model ◽

Effective Vaccine ◽

Human Brucellosis ◽

Sublingual Administration ◽

Protective Properties ◽

Vector Vaccine ◽

Guinea Pig Model

Abstract Background: A new candidate vector vaccine against human brucellosis based on recombinant influenza viral vectors (rIVV) subtypes H5N1 expressing Brucella Omp16, L7/L12, Omp19 or Cu-Zn SOD proteins has been developed. This paper presents the results of the study of the safety and protective properties of the vaccine with various options of administering, dosing and frequency of use on guinea pigs.Methods: The safety of the vaccine was assessed based on the general condition, behavior and dynamics of a guinea pig weight-gain test. The effectiveness of the new anti-brucellosis vector vaccine was determined by studying its protective effect after conjunctival, intranasal and sublingual administration in doses 105 EID50, 106 EID50 and 107 EID50 during prime and boost vaccinations of animals, followed by challenge with a virulent strain of B. mellitensis 16M infection. For sake of comparison, the commercial B. melitensis Rev.1 vaccine was used as a control. The protective properties of vaccines were assessed by quantitation of Brucella colonization in organs and tissues of infected animals and compared to the control groups.Results: It was found that the vaccine after prime and booster immunization using conjunctival, intranasal and sublingual routes of administration, as well as after using various doses of vaccine were safe for guinea pigs. The most optimal way of using the vaccine has been established: double intranasal immunization of guinea pigs at a dose of 106 EID50, which provides 80% protection of guinea pigs from B. melitensis 16M infection (P < 0.05), which is comparable to the results of the effectiveness of the commercial B. melitensis Rev.1 vaccine.Conclusions: We developed effective vaccine candidate against brucellosis and developed its immunization protocol in guinea pig model. We believe that this study is a substantial step for using the vaccine for future pre-clinical and clinical trials in human.

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