scholarly journals PneumococcalSurface Protein A Is Expressed In Vivo, and Antibodies to PspA AreEffective for Therapy in a Murine Model of PneumococcalSepsis

2003 ◽  
Vol 71 (12) ◽  
pp. 7149-7153 ◽  
Author(s):  
E. Swiatlo ◽  
J. King ◽  
G. S. Nabors ◽  
B. Mathews ◽  
D. E. Briles
Keyword(s):  
Northern Blot Analysis ◽  
Lethal Dose ◽  
Protein A ◽  
Surface Protein ◽  
Immune Serum ◽  
Invasive Infection ◽  
Pneumococcal Infections ◽  
Type 3

ABSTRACT Pneumococcal surface protein A (PspA) is an immunogenic protein expressed on the surface of all strains of Streptococcus pneumoniae (pneumococcus) and induces antibodies which protect against invasive infection in mice. Pneumococci used for infectious challenge in protection studies are typically collected from cultures grown in semisynthetic medium in vitro. The purpose of these studies is to confirm that PspA is expressed by pneumococci during growth in vivo at a level sufficient for antibodies to PspA to be protective. Mice were actively immunized with purified PspA or by passive transfer of monoclonal antibody (MAb) and challenged with a capsular type 3 strain in diluted whole blood from bacteremic mice. All were protected against challenge with 10 times the 50% lethal dose (LD50), and mice challenged with 1,000 times the LD50 had increased survival compared with controls. Additionally, nonimmune mice treated with MAbs to PspA or PspA immune serum at 6 and 12 h after infection with 10 times the LD50 also showed increased survival. Northern blot analysis of RNA from pneumococci grown either in vitro or in vivo showed similar levels of PspA mRNA. These results demonstrate that PspA is expressed in vivo in a mouse model and that immunization with PspA induces antibodies to an antigen which is expressed during the course of invasive infection. Immunotherapy with antibodies to PspA may have some utility in treating pneumococcal infections in humans.

scholarly journals A SPECIFIC POISON IN THE LIVER EXTRACTS OF RABBITS INOCULATED WITH TYPHOID AND PRODIGIOSUS BACILLI INTRAVENOUSLY

1918 ◽  
Vol 28 (5) ◽  
pp. 571-583
Author(s):  
Julia T. Parker
Keyword(s):  
Anaphylactic Shock ◽  
Liver Extract ◽  
Lethal Dose ◽  
Toxic Substance ◽  
Normal Liver ◽  
Immune Serum ◽  
Minimum Lethal Dose ◽  
Lethal Doses

1. The livers of rabbits inoculated with cultures of Bacillus typhosus or Bacillus prodigiosus under certain conditions contain a toxic substance extractable with salt solution. When the toxic extracts are injected intravenously into normal rabbits the latter animals develop symptoms resembling those of anaphylactic shock and succumb. The lethal doses of the toxic extracts are far smaller than those of normal liver extract. 2. The livers of rabbits injected with typhoid antigen also yield a toxic extract. 3. Boiling as well as filtration through a Berkefeld filter only partially detoxicates the extract. 4. Tolerance to one to two lethal doses of the poisonous extracts can be induced by cautious immunization. 5. Rabbits actively immunized to Bacillus typhosus or Bacillus prodigiosus usually resist one lethal dose of the homologous liver poison; and animals tolerant to the typhoid liver poison resist one minimum lethal dose at least of Bacillus typhosus. 6. Typhoid immune serum is not detoxicating either in vivo or in vitro for the typhoid liver poison. 7. The liver poisons are specific, since rabbits actively immunized to either Bacillus typhosus or Bacillus prodigiosus withstand at least one minimum lethal dose of the homologous but not of the heterologous-liver poisons.

scholarly journals Enzymatic Hydrolysis of Pneumococcal Capsular Polysaccharide Renders the Bacterium Vulnerable to Host Defense

2018 ◽  
Vol 86 (8) ◽  
Author(s):  
Dustin R. Middleton ◽  
Amy V. Paschall ◽  
Jeremy A. Duke ◽  
Fikri Y. Avci
Keyword(s):  
Enzymatic Hydrolysis ◽  
Capsular Polysaccharide ◽  
Protective Role ◽  
Pneumococcal Infections ◽  
Content Type ◽  
Drug Resistant Strains ◽  
Type 3 ◽  
Hydrolysis Of

ABSTRACTDespite a century of investigation,Streptococcus pneumoniaeremains a major human pathogen, causing a number of diseases, such as pneumonia, meningitis, and otitis media. Like many encapsulated pathogens, the capsular polysaccharide (CPS) ofS. pneumoniaeis a critical component for colonization and virulence in mammalian hosts. This study aimed to evaluate the protective role of a glycoside hydrolase, Pn3Pase, targeting the CPS of type 3S. pneumoniae, which is one of the most virulent serotypes. We have assessed the ability of Pn3Pase to degrade the capsule on a live type 3 strain. Throughin vitroassays, we observed that Pn3Pase treatment increases the bacterium's susceptibility to phagocytosis by macrophages and complement-mediated killing by neutrophils. We have demonstrated thatin vivoPn3Pase treatment reduces nasopharyngeal colonization and protects mice from sepsis caused by type 3S. pneumoniae. Due to the increasing shifts in serotype distribution, the rise in drug-resistant strains, and poor immune responses to vaccine-included serotypes, it is necessary to investigate approaches to combat pneumococcal infections. This study evaluates the interaction of pneumococcal CPS with the host at molecular, cellular, and systemic levels and offers an alternative therapeutic approach for diseases caused byS. pneumoniaethrough enzymatic hydrolysis of the CPS.

scholarly journals Some Fundamental Experiments on Immunity, Illustrated

1904 ◽  
Vol 4 (1) ◽  
pp. 31-72 ◽  
Author(s):  
E. F. Bashford
Keyword(s):  
Lethal Dose ◽  
Test Tube ◽  
Immune Serum ◽  
Normal Serum ◽  
Weight Of Evidence ◽  
Passive Immunity ◽  
Artificial Immunity ◽  
The Difference

By means of the graphic records given on Plates II–VI and VIII the following facts have been illustrated.Immunity to Erythrocytes.Normal rabbit's serum is relatively innocuous for bullock's erythrocytes. The serum of an immunised rabbit acquires the power to dissolve bullock's erythrocytes.Besides acquiring the power to dissolve bullock's erythrocytes, an immune serum may also acquire power to clump them, and it has been shown that the phenomena of haemolysis and of agglutination are independent.The powers acquired by the immune serum can be artificially modified. The serum may be deprived of its powers by heat. Serum cautiously so deprived of its haemolytic power can have it restored by the addition of normal serum. The haemolytic power of the un-heated serum is augmented if normal serum be superadded.It has been shown that an immune serum only differs from a normal serum by its containing antitoxic bodies which are endowed with powers of specific reaction with the bullock's erythrocytes.The mechanism by which erythrocytes are laked by an immune serum has been analysed, and it has been shown that the solution of the erythrocytes is effected through the intervention of an anti-erythrocytic body called forth by immunisation. The erythrocytes which have been subjected to the action of this product of immunity give indication of their reaction with it if they are subsequently or concomitantly placed under the influence of normal serum. The erythrocytes and normal serum together, therefore, form a combined indicator of the presence of the anti-eiythrocytic body. The part played by normal serum has nothing to do with the acquisition of immunity.The only conclusion drawn from the above observations is that in the production of immunity to erythrocytes the serum of the immunised animal acquires certain powers which are concomitant with, but are not necessarily the cause of the immunity. This special case of immunity to erythrocytes is therefore probably parallel to induced immunity to those bacterial toxines for which antitoxines are known to exist.The course and progressive augmentation of artificial immunity to erythrocytes has also been illustrated, and it has been shown that erythrocytes saturated with anti-erythrocytic body retain the power to augment the immunity of an already immune animal.The serum of an animal actively immunised has power to confer passive immunity upon other animals, and the course of this passive immunity differs in the two cases when it is induced in the same species and in a species alien to that providing the immune serum.The experiments with bullock's erythrocytes have been repeated in parallel observations with ricin in order to permit of the observations on haemolysis being utilised in drawing conclusions on the behaviour of bacterial toxines.By adjusting the conditions of experiment in such a way that the minimal lethal dose for an animal was also the minimal agglutinating dose in test-tube experiments, it has been possible to give graphic records showing the parallelism between the processes when erythrocytes or living animals are used as indicators of the presence of free ricin. In this way it has been possible to illustrate the determination of the minimal lethal and minimal agglutinating doses of ricin and that quantity of antitoxine (antiricin) which is necessary to abolish the corresponding actions in the animal and in the test-tube, and to show that the mixture of toxine and antitoxine which is physiologically neutral in vitro is also physiologically neutral in vivo within the limitations imposed by the preliminary determinations.The consequences of conferring passive immunity upon the guinea-pig by means of active immune serum of the rabbit have also been illustrated, and it has been shown that the alien antiricin serum leads to the production of agencies directed against itself.Ricin neutralised by antiricin retains its power to produce immunity when injected into the species of animal which has yielded the antiricin.In connection with the conference of immunity to erythrocytes and to ricin, the nature of the difference between normal and immune sera has been studied. Attention has been directed to the possession by normal sera of properties which simulate those possessed in more marked degree by the immune sera. In the case of haemolysis, it has not been possible to clearly demonstrate that the actions manifested by the normal and immune sera are distinct, although the weight of evidence is in favour of this view. In the case of ricin, however, it has been possible to demonstrate that the immune serum possesses properties which are quite distinct from those possessed by normal serum, and that the latter does not interfere with the action of ricin because of the natural presence of a trace of antiricin. In the case of immunity to ricin, the antitoxine is certainly something which has been super-added to the serum in consequence of the process of immunisation.The facts ascertained in regard to artificial immunity to erythrocytes and to ricin completely agree. Only in oue point is it impossible to be quite sure that the phenomena are identical, viz., in the simulation by normal serum of the powers characteristic of the immune serum; for the demonstration that the two are distinct has been possible for ricin, but open to doubt in the case of erythrocytes. My investigations have been extended to diphtheria and tetanus toxines and to cobra venom, kindly placed at my disposal by Sir Thomas R. Fraser. They have however been interrupted, but so far as they go they support fully the observations made on ricin and erythrocytes.

scholarly journals Rapid and Broad Immune Efficacy of a Recombinant Five-Antigen Vaccine against Staphylococcus aureus Infection in Animal Models

Vaccines ◽  
2020 ◽  
Vol 8 (1) ◽  
pp. 134 ◽  
Author(s):  
Hao Zeng ◽  
Feng Yang ◽  
Qiang Feng ◽  
Jinyong Zhang ◽  
Jiang Gu ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Severe Disease ◽  
Lethal Dose ◽  
Protein A ◽  
Surface Proteins ◽  
Staphylococcal Protein A ◽  
Humoral Immune ◽  
Aureus Infection

Staphylococcus aureus (S. aureus) is a leading cause of both healthcare-and community-associated infections globally, which result in severe disease and readily developing antibiotic resistance. Developing an efficacious vaccine against S. aureus is urgently required. In the present study, we selected five conserved antigens, including the secreted factors α-hemolysin (Hla), staphylococcal enterotoxin B (SEB) and the three surface proteins staphylococcal protein A (SpA), iron surface determinant B N2 domain (IsdB-N2) and manganese transport protein C (MntC). They were all well-characterized virulence factor of S. aureus and developed a recombinant five-antigen S. aureus vaccine (rFSAV), rFSAV provided consistent protection in S. aureus lethal sepsis and pneumonia mouse models, and it showed broad immune protection when challenged with a panel of epidemiologically relevant S. aureus strains. Meanwhile, rFSAV immunized mice were able to induce comprehensive cellular and humoral immune responses to reduce bacterial loads, inflammatory cytokine expression, inflammatory cell infiltration and decrease pathology after challenge with a sub-lethal dose of S. aureus. Moreover, the importance of specific antibodies in protection was demonstrated by antibody function tests in vitro and in vivo. Altogether, our data demonstrate that rFSAV is a potentially promising vaccine candidate for defensing against S. aureus infection.

scholarly journals Both Innate Immunity and Type 1 Humoral Immunity to Streptococcus pneumoniae Are Mediated by MyD88 but Differ in Their Relative Levels of Dependence on Toll-Like Receptor 2

2005 ◽  
Vol 73 (1) ◽  
pp. 298-307 ◽  
Author(s):  
Abdul Q. Khan ◽  
Quanyi Chen ◽  
Zheng-Qi Wu ◽  
James C. Paton ◽  
Clifford M. Snapper
Keyword(s):  
Streptococcus Pneumoniae ◽  
Humoral Immunity ◽  
Protein A ◽  
Surface Protein ◽  
Lethal Challenge ◽  
Humoral Immune ◽  
Extracellular Bacterium

ABSTRACT Little is known regarding the role of Toll-like receptors (TLRs) in regulating protein- and polysaccharide-specific immunoglobulin (Ig) isotype production in response to an in vivo challenge with an extracellular bacterium. In this report we demonstrate that MyD88−/−, but not TLR2−/−, mice are markedly defective in their induction of multiple splenic proinflammatory cytokine- and chemokine-specific mRNAs after intraperitoneal (i.p.) challenge with heat-killed Streptococcus pneumoniae capsular type 14 (S. pneumoniae type 14). This is correlated with analogous responses in splenic cytokine protein release in vitro following addition of S. pneumoniae type 14. Consistent with these data, naïve MyD88−/−, but not TLR2−/−, mice are more sensitive to killing following i.p. challenge with live S. pneumoniae type 14, relative to responses in wild-type mice. However, prior immunization of MyD88−/− mice with heat-killed S. pneumoniae type 14 protects against an otherwise-lethal challenge with live S. pneumoniae type 14. Surprisingly, both MyD88−/− and TLR2−/− mice exhibit striking and equivalent defects in elicitation of type 1 IgG isotypes (IgG3, IgG2b, and IgG2a), but not the type 2 IgG isotype, IgG1, specific for several protein and polysaccharide antigens, in response to i.p. challenge with heat-killed S. pneumoniae type 14. Of note, the type 1 IgG isotype titers specific for pneumococcal surface protein A are reduced in MyD88−/− mice but not TLR2−/− mice. These data suggest that distinct TLRs may differentially regulate innate versus adaptive humoral immunity to intact S. pneumoniae and are the first to implicate a role for TLR2 in shaping an in vivo type 1 IgG humoral immune response to a gram-positive extracellular bacterium.

scholarly journals Inactivation of the srtA Gene inStreptococcus gordonii Inhibits Cell Wall Anchoring of Surface Proteins and Decreases In Vitro and In Vivo Adhesion

2001 ◽  
Vol 69 (1) ◽  
pp. 75-80 ◽  
Author(s):  
Tové C. Bolken ◽  
Christine A. Franke ◽  
Kevin F. Jones ◽  
Gloria O. Zeller ◽  
C. Hal Jones ◽  
...  
Keyword(s):  
Cell Wall ◽  
Protein A ◽  
Surface Protein ◽  
Surface Proteins ◽  
Gram Positive ◽  
Gram Positive Bacteria ◽  
Human Fibronectin ◽  
Gram Positive Cocci

ABSTRACT The srtA gene product, SrtA, has been shown to be required for cell wall anchoring of protein A as well as virulence in the pathogenic bacterium Staphylococcus aureus. There are five major mechanisms for displaying proteins at the surface of gram-positive bacteria (P. Cossart and R. Jonquieres, Proc. Natl. Acad. Sci. USA 97:5013–5015, 2000). However, since many of the known surface proteins of gram-positive bacteria are believed to be exported and anchored via the sortase pathway, it was of interest to determine ifsrtA plays a similar role in other gram-positive bacteria. To that end, the srtA gene in the human oral commensal organism Streptococcus gordonii was insertionally inactivated. The srtA mutant S. gordoniiexhibited a marked reduction in quantity of a specific anchored surface protein. Furthermore, the srtA mutant had reduced binding to immobilized human fibronectin and had a decreased ability to colonize the oral mucosa of mice. Taken together, these results suggest that the activity of SrtA plays an important role in the biology of nonpathogenic as well as pathogenic gram-positive cocci.

scholarly journals Pneumococcal Surface Protein A Inhibits Complement Activation by Streptococcus pneumoniae

1999 ◽  
Vol 67 (9) ◽  
pp. 4720-4724 ◽  
Author(s):  
Anh-Hue T. Tu ◽  
Robert L. Fulgham ◽  
Mark A. McCrory ◽  
David E. Briles ◽  
Alexander J. Szalai
Keyword(s):  
Streptococcus Pneumoniae ◽  
Defense Mechanisms ◽  
Alternative Pathway ◽  
Protein A ◽  
Surface Protein ◽  
Serum Complement ◽  
Factor B ◽  
Pneumococcal Surface Protein A

ABSTRACT Pneumococcal surface protein A (PspA) is a surface-exposed protein virulence factor for Streptococcus pneumoniae. In this study, no significant depletion of serum complement was observed for the serum of mice infected with pneumococci that express PspA. In contrast, in mice infected with an isogenic strain of pneumococci lacking PspA, significant activation of serum complement was detected within 30 min after infection. Also, the PspA-deficient strain but not the PspA-expressing strain was cleared from the blood within 6 h. The contribution of PspA to pneumococcal virulence was further investigated by using mice deficient for C5, C3, or factor B. In mice deficient for C3 or factor B, PspA-negative pneumococci became fully virulent. In contrast, in C5-deficient mice as in wild-type mice, PspA-deficient pneumococci were avirulent. These in vivo data suggest that, in nonimmune mice infected with pneumococci, PspA interferes with complement-dependent host defense mechanisms mediated by factor B. Immunoblots of pneumococci opsonized in vitro suggested that more C3b was deposited on PspA-negative than on PspA-positive pneumococci. This was observed with and without anticapsular antibody. Furthermore, processing of the α chain of C3b was reduced in the presence of PspA. We propose that PspA exerts its virulence function by interfering with deposition of C3b onto pneumococci and/or by inhibiting formation of a fully functional alternative pathway C3 convertase. By blocking recruitment of the alternative pathway, PspA reduces the amount of C3b deposited onto pneumococci, thereby reducing the effectiveness of complement receptor-mediated pathways of clearance.

scholarly journals Pertussis Toxin Improves Immune Responses to a Combined Pneumococcal Antigen and Leads to Enhanced Protection against Streptococcus pneumoniae

2014 ◽  
Vol 21 (7) ◽  
pp. 972-981 ◽  
Author(s):  
Carolina Salcedo-Rivillas ◽  
Anne-Sophie Debrie ◽  
Eliane Namie Miyaji ◽  
Jorge M. C. Ferreira ◽  
Isaías Raw ◽  
...  
Keyword(s):  
Streptococcus Pneumoniae ◽  
Pertussis Toxin ◽  
Protein A ◽  
Passive Immunization ◽  
Surface Protein ◽  
Interleukin 17 ◽  
Adjuvant Activity ◽  
Content Type

ABSTRACTPneumococcal surface protein A (PspA) is a candidate antigen for the composition of protein-based vaccines againstStreptococcus pneumoniae. While searching for efficient adjuvants for PspA-based vaccines, our group has described the potential of combining PspA with the whole-cell pertussis vaccine (wP). When given to mice through the nasal route, a formulation composed of PspA from clade 5 (PspA5) and wP (PspA5-wP) induced high levels of antibodies and protection against challenges with different pneumococcal strains. PspA5-wP also induced the secretion of interleukin 17 (IL-17) by splenocytes and the infiltration of leukocytes in the lungs after challenge. Here, we show that protection against a pneumococcal invasive challenge was completely abrogated in μMT−/−mice, which are deficient in the maturation of B cells, illustrating the importance of antibodies in the survival elicited by the PspA5-wP vaccine. Moreover, passive immunization showed that IgG purified from the sera of mice immunized with PspA5-wP conferred significant protection to naive mice, whereas the respective F(ab′)2did not. Additionally,in vivodepletion of complement abolished protection against the pneumococcal challenge. The combination of PspA5 with wild-type or mutantBordetella pertussisstrains or with purified components showed that the pertussis toxin (PT)-containing formulations induced the highest levels of antibodies and protection. This suggests that the adjuvant activity of wP in the PspA5 model is mediated at least in part by PT. The sera from mice immunized with such formulations displayed high IgG binding and induction of complement deposition on the pneumococcal surfacein vitro, which is consistent with thein vivoresults.

Hepato- and Nephroprotective Effects of the Polyphenol Concentrate From Cabernet Sauvignon Grape Varieties Cultivated in Kazakhstan in the Experimental Model Of CCL4-Induced Toxicity

2017 ◽  
Vol 9 (03) ◽  
Author(s):  
Nurgozhin T. ◽  
Sergazy S. H. ◽  
Adilgozhina G. ◽  
Gulyayev A. ◽  
Shulgau Z. ◽  
...  
Keyword(s):  
Carbon Tetrachloride ◽  
Experimental Model ◽  
Lethal Dose ◽  
Radical Scavenging ◽  
Cabernet Sauvignon ◽  
Intragastric Administration ◽  
Liver And Kidney ◽  
Antioxidant Stress

Objective:This study investigates the hepatoprotective effect and the antioxidant role of polyphenol concentrate in the experimental model of carbon tetrachloride (CCl4) induced toxicity. Methods: Antioxidant activity of Cabernet Sauvignon grape polyphenol were evaluated by radical scavenging of 1,1-diphenyl-2-picryl hydrazyl radical (DPPH), 2,2’-azinobis(3-ethylbenzthiazoline-6-sulfonic acid) (ABTS.+). In addition, the effects of polyphenol concentrate on the survival of Wistar rats in the toxicity model, was also investigated. The polyphenol concentrate was administered for 5 five days prior to injection of carbon tetrachloride in a sub-lethal dose of 300 mg/kg of animal body weight in order to perform histological examinations of the liver and kidney, and detect the levels of AST, ALT and bilirubin. Results: Administration of polyphenol concentrate increased animal survival in the experimental model. Moreover, the intragastric administration of polyphenol concentrate prior to the initiation of the experimental model of toxicity, which was caused by a sub-lethal CCl4 dose, reduced morphological injuries in the liver and kidney, decreased the AST and ALT levels of the blood serum. Discussion and conclusion: Our data demonstrate that polyphenol concentrate possesses an antioxidant potential both in vitro and in vivo by reducing antioxidant stress that was caused by CCl4 administration into rats.

In Vitro and In Vivo Neutralizing Activity of Uvaria chamae Leaves Fractions on the Venom of Naja nigricollis in Albino Rat and Bovine Blood

2020 ◽  
Vol 14 (4) ◽  
pp. 295-311
Author(s):  
Ada Gabriel ◽  
Mamman Mohammed ◽  
Mohammed G. Magaji ◽  
Yusuf P. Ofemile ◽  
Ameh P. Matthew ◽  
...  
Keyword(s):  
Ethyl Acetate ◽  
Neglected Tropical Diseases ◽  
Lethal Dose ◽  
Positive Control ◽  
Haemolytic Activity ◽  
Cytotoxic Activities ◽  
Albino Rat ◽  
Aqueous Residue

Background: Snakebite envenomation is a global priority ranked top among other neglected tropical diseases. There is a folkloric claim that Uvaria chamae is beneficial for the management of snakebite and wounds in African ethnobotanical surveys. Besides, there are many registered patents asserting the health benefits of U. chamae. Objective: This study aimed to investigate U. chamae’s potentials and identify candidates for the development of tools for the treatment and management of N. nigricollis envenomation. Methods: Freshly collected U. chamae leaves were air-dried, powdered, and extracted in methanol. The median lethal dose of the extract was determined and further fractionated with n-hexane, n-butanol and ethyl acetate. Each fraction was tested for neutralizing effect against venom-induced haemolytic, fibrinolytic, hemorrhagic, and cytotoxic activities. Results: U. chamae fractions significantly (p<0.05) neutralized the haemolytic activity of N. nigricollis venom in n-butanol; 31.40%, n-hexane; 33%, aqueous residue; 39.60% and ethyl acetate; 40.70% at the concentration of 100mg/ml of each fraction against 10mg/ml of the snake venom when compared to the positive control. The fibrinolytic activity of N. nigricollis venom was significantly (p<0.05) neutralized in n-hexane at 73.88%, n-butanol; 72.22% and aqueous residue; 72.22% by the fractions of U. chamae. In addition, haemorrhagic activity of N. nigricollis venom was significantly (p<0.05) neutralized by U. chamae fractions at the concentrations of 100mg/ml, 200mg/ml and 400mg/ml except for n-butanol and aqueous residues at 400 mg/ml. Conclusion: U. chamae leaves fractions possess a high level of protection against N. nigricollis venoms-induced lethality and thus validate the pharmacological rationale for its usage in the management of N. nigricollis envenomation.

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