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Infection and Immunity May 1977The lipopolysaccharides and free lipid A from several strains of Rhodospirillaceae were assayed comparatively with those of Enterobacteriaceae in a number of biological...
The lipopolysaccharides and free lipid A from several strains of Rhodospirillaceae were assayed comparatively with those of Enterobacteriaceae in a number of biological tests. Free lipid A's from Rhodopseudomonas gelatinosa and Rhodospirillum tenue exhibited strong serological cross-reactions with each other and with free lipid A from Salmonella. Lipid A's from Rhodopseudomonas viridis and Rhodopseudomonas palustris, although cross-reacting with each other, did not do so with either the lipid A of R. gelatinosa or R. tenue or with that of Salmonella. The presence or absence of the above cross-reactions agreed with corresponding similarities or differences in the chemical structure of the lipid A preparations. The lipopolysaccharide of R. gelatinosa was highly toxic for adrenalectomized mice and pyrogenic for rabbits; however, it exhibited no anti-complementary activity. The activity of the R. tenue lipopolysaccharide was very low in both the lethality and pyrogenicity tests. Its corresponding free lipid A also exhibited low pyrogenic activity; however, its lethal toxicity for adrenalectomized mice was considerably higher than that of the intact parent lipopolysaccharide. Both intact lipopolysaccharide and, unexpectedly, the free lipid A exhibited no anti-complementary activity. The lipopolysaccharides of R. viridis and R. palustris were virtually nontoxic for mice and nonpyrogenic for rabbits. Both lipopolysaccharides were highly potent in their interaction with complement. They therefore represent the first example of nontoxic lipopolysaccharides exhibiting high anti-complementary activity.
Topics: Animals; Complement System Proteins; Cross Reactions; Hemagglutination Inhibition Tests; Immune Sera; Lethal Dose 50; Lipid A; Lipopolysaccharides; Pyrogens; Rabbits; Rhodospirillaceae; Salmonella
PubMed: 558961
DOI: 10.1128/iai.16.2.407-412.1977 -
The Yale Journal of Biology and Medicine 1982Concepts of fever from Hippocrates to the present are briefly outlined and compared with current ideas of the pathogenesis of fever. Evidence is presented that...
Concepts of fever from Hippocrates to the present are briefly outlined and compared with current ideas of the pathogenesis of fever. Evidence is presented that endogenous pyrogen, the hormone that elevates body temperature, is identical with lymphocyte-activating factor, a monokine that stimulates lymphocyte proliferation and function.It now appears that inflammation and fever are closely interrelated phenomena that are modulated by a single hormone and that have been selected by evolution to protect the host against infection.
Topics: Amines; Animals; Biological Evolution; Fever; History, 18th Century; History, 19th Century; History, 20th Century; History, Ancient; Humans; Inflammation; Interleukin-1; Monocytes; Prostaglandins; Pyrogens
PubMed: 6758374
DOI: No ID Found -
ALTEX 2016The rabbit pyrogen test was developed in the early 1900's to detect contaminating pyrogens in parenteral medicines. Since its conception alternative methods with...
The rabbit pyrogen test was developed in the early 1900's to detect contaminating pyrogens in parenteral medicines. Since its conception alternative methods with improved sensitivity, relevancy and which are ethically more acceptable have been developed. However, the test is a current Pharmacopeial method and is used to evaluate the pyrogen content of some vaccines. In this article the limitations and pitfalls of using the test to measure pyrogenicity of vaccines containing outer membrane vesicles are described. The method is unsuitable as a safety test for these products due to the high levels of endotoxin present in the vaccine which generate a pyrogenic response in rabbits when delivered intravenously without any dilution. Its use as a consistency test is also ambiguous as the test gives a qualitative rather than quantitative response and the rabbit models are highly variable. In addition there is evidence that measuring the temperature rise of the animals over three hours does not capture the maximum fever response. Finally the article considers the use of alternative methods and the validity of animal models when applying a consistency based approach for assessing the quality of licensed products.
Topics: Animal Testing Alternatives; Animals; Endotoxins; Meningococcal Vaccines; Models, Animal; Monocytes; Pyrogens; Rabbits
PubMed: 26626274
DOI: 10.14573/altex.1509291 -
British Medical Journal Feb 1973Plasma corticotrophin (ACTH) and corticosteroid levels in response to lysine vasopressin (LVP), insulin hypoglycaemia, and pyrogen have been compared in seven subjects...
Plasma corticotrophin (ACTH) and corticosteroid levels in response to lysine vasopressin (LVP), insulin hypoglycaemia, and pyrogen have been compared in seven subjects with normal pituitary adrenal function. Intramuscular vasopressin was a weak stimulus to corticotrophin release, peak values lying within the range 49 to 141 pg/ml. Insulin hypoglycaemia consistently caused a more noticeable increase, with peak levels between 114 and 364 pg/ml, while pyrogen was the most powerful, corticotrophin levels rising to between 209 and 1,725 pg/ml. Peak plasma corticosteroid levels showed less pronounced differences between the three tests, and correlated poorly with peak ACTH levels. Thus, relatively small acute changes in corticotrophin levels produce near-maximal adrenal stimulation. Under these conditions, plasma corticosteroid measurements do not accurately reflect circulating corticotrophin levels. These findings help to explain the physiological basis of several observations on the corticosteroid responses to these clinical test procedures.
Topics: 11-Hydroxycorticosteroids; Adolescent; Adrenal Cortex Hormones; Adrenal Glands; Adrenocorticotropic Hormone; Adult; Blood Glucose; Female; Humans; Insulin; Male; Middle Aged; Pituitary Gland; Pyrogens; Secretory Rate; Stimulation, Chemical; Time Factors; Vasopressins
PubMed: 4346579
DOI: 10.1136/bmj.1.5848.267 -
Biologicals : Journal of the... Nov 2023The rabbit pyrogen test (RPT) was the benchmark for pyrogenicity testing, but scientific advancements have provided innovative and humane methods, such as the in vitro...
The rabbit pyrogen test (RPT) was the benchmark for pyrogenicity testing, but scientific advancements have provided innovative and humane methods, such as the in vitro monocyte-activation test (MAT). However, transitioning from the RPT to the MAT has been challenging. The European Directorate for the Quality of Medicines & HealthCare, the Council of Europe, and the European Partnership for Alternative Approaches to Animal Testing jointly hosted an international conference entitled "The future of pyrogenicity testing: phasing out the rabbit pyrogen test". The conference aimed to show how the European Pharmacopoeia intends to remove the RPT from its texts by 2026, facilitate the use of MAT, and identify gaps in the suppression of RPT. The events contributed to a better understanding of the barriers to RPT replacement and acceptance of in vitro alternatives. Participants comprised stakeholders from Asia, Europe, and North America, including vaccine developers, contract laboratories, and regulators. Participants shared their replacement strategies and experiences with MAT implementation. They emphasised the need for continued cooperation between stakeholders and stressed the importance of international harmonisation of regulatory requirements to help accelerate MAT acceptance outside Europe. Despite the challenges, the willingness to eliminate the unnecessary use of RPT was common across all participants.
Topics: Animals; Rabbits; Humans; Pyrogens; Monocytes; Meningococcal Vaccines; Laboratories; Europe; Animal Testing Alternatives
PubMed: 37643507
DOI: 10.1016/j.biologicals.2023.101702 -
Microbes and Infection Nov 2000Increasing evidence indicates that apoptosis of the host cell may constitute a defense mechanism to confine the infection by bacterial pathogens. Certain pathogens have... (Review)
Review
Increasing evidence indicates that apoptosis of the host cell may constitute a defense mechanism to confine the infection by bacterial pathogens. Certain pathogens have developed elegant mechanisms to modulate the fate of the host cell, which include induction or blockage of apoptosis. These studies will promote our understanding of the pathogenesis of infectious diseases and aid the development of means for therapeutic intervention.
Topics: Animals; Apoptosis; Bacteria; Bacterial Proteins; Bacterial Toxins; Caspases; Exotoxins; Heat-Shock Proteins; Hemolysin Proteins; Humans; Membrane Proteins; Models, Biological; Pyrogens
PubMed: 11137044
DOI: 10.1016/s1286-4579(00)01326-5 -
Temperature (Austin, Tex.) 2015Concordance between lipopolysaccharide and platelet activating factor - mediated events have suggested that the latter likely mediates all effects induced by the former....
Concordance between lipopolysaccharide and platelet activating factor - mediated events have suggested that the latter likely mediates all effects induced by the former. In this issue of Temperature, Steiner and Romanovsky challenge this notion, showing that while platelet activating factor is a potent pyrogenic mediator, the thermoregulatory responses to lipopolysaccharide are instead induced by prostaglandins.
PubMed: 27227061
DOI: 10.1080/23328940.2015.1096439 -
ALTEX 2020Pyrogen content is a key quality feature that must be checked in all injectable products, including vaccines. Four tests are currently available in the European...
Pyrogen content is a key quality feature that must be checked in all injectable products, including vaccines. Four tests are currently available in the European Pharmacopoeia to monitor pyrogen/endotoxin presence: the rabbit pyrogen test (RPT), the bacterial endotoxin test, the recombinant factor C test, and the monocyte activation test (MAT). Here, we explored the possibility to replace the RPT with the MAT in the quality control of a vaccine against tick-borne encephalitis virus (TBEV). The testing was carried out using cryopreserved peripheral blood mononuclear cells as cell source. IL-6 release was selected as readout for the detection of both endotoxin and non-endotoxin contaminants. MAT applicability for pyrogen testing of the TBEV vaccine was assessed through preparatory tests and resulted in the establishment of a very sensitive assay (limit of detection (LOD) = 0.04 EU/mL; sensitivity = 0.1 EU/mL). Both quantitative Method A and semiquantitative Method B were used for data analysis. Our studies revealed that for a vaccine without intrinsic pyrogenicity, such as that against TBEV, sensitivity (the lowest endotoxin value of the standard curve) should be used instead of LOD to define a stable maximum valid dilution of the product. In conclusion, we describe the challenges of MAT implementation for anti-TBEV vaccine following the current Ph. Eur. chapter 2.6.30 and propose a re-evaluation of the validity criteria of Methods A and B in order to set a semi-quantitative or limit test suitable for those products for which a reference lot comparison analysis is not applicable or favorable.
Topics: Animal Testing Alternatives; Animals; Cells, Cultured; Cytokines; Encephalitis Viruses, Tick-Borne; Endotoxins; Humans; Leukocytes, Mononuclear; Monocytes; Pyrogens; Quality Control; Rabbits; Viral Vaccines
PubMed: 32488289
DOI: 10.14573/altex.2002252 -
The Journal of Physiology Aug 2000Interleukin (IL)-6 is an important mediator of the host response to disease and has been proposed, largely based upon circumstantial evidence, as the principal...
Interleukin (IL)-6 is an important mediator of the host response to disease and has been proposed, largely based upon circumstantial evidence, as the principal endogenous circulating pyrogen responsible for activating CNS mechanisms in fever during infection and inflammation. In the present investigation, we studied the role of peripheral IL-6 in fever and its relationship with IL-1, itself an important endogenous pyrogen and a potent stimulus of IL-6 production. Injection of lipopolysaccharide (LPS) into a sterile, subcutaneous air pouch (i.po.) in rats evoked an increase in body temperature which peaked at 3 h, and which was abolished in animals pretreated (intraperitoneally) with IL-6 antiserum. The increase in body temperature was accompanied by a significant elevation in concentrations of (immunoreactive) IL-1 and IL-6 at the site of inflammation (pouch), but only IL-6 in the circulation and cerebrospinal fluids. We propose that much of the circulating IL-6 originates at the site of inflammation, since injection of human recombinant (hr)IL-6 (i.po.) was detected (10 min after the injection) in the plasma using an ELISA specific for human IL-6. However, despite the relatively high concentration of IL-6 injected (25 microg kg-1, i.po.), this cytokine had no effect on body temperature when injected alone, but did induce fever when co-injected with a non-pyrogenic dose (when given alone) of IL-1beta, and exacerbated the fever to a pyrogenic dose of IL-1beta. The results from the present study demonstrate that IL-6 is a circulating endogenous pyrogen during LPS-induced fever, which acts in concert with IL-1beta at the local site of inflammation, before entering the circulation. Circulating IL-6 can then activate CNS mechanisms resulting in the development of the febrile response during disease.
Topics: Analysis of Variance; Animals; Body Temperature; Disease Models, Animal; Dose-Response Relationship, Drug; Drug Synergism; Fever; Immune Sera; Inflammation; Injections, Intraperitoneal; Injections, Subcutaneous; Interleukin-1; Interleukin-6; Lipopolysaccharides; Male; Rats; Rats, Sprague-Dawley; Recombinant Proteins; Skin
PubMed: 10922015
DOI: 10.1111/j.1469-7793.2000.00653.x -
ALTEX 2015The whole blood pyrogen test was first described in this journal exactly twenty years ago. It employs the cytokine response of blood monocytes for the detection of...
The whole blood pyrogen test was first described in this journal exactly twenty years ago. It employs the cytokine response of blood monocytes for the detection of microbiological contaminants with the potential to finally replace the still broadly used rabbit pyrogen test. The article reviews its development process, the current status of the test as well as the challenges and missed opportunities. The article highlights the enormous efforts of many people to get the test to where it is today. But it also shows the incredible missed opportunities for implementation and thus sparing about 400,000 rabbits still used for this purpose per year worldwide; in the EU, since the official acceptance of the test, the number of animals used for pyrogen testing did not fall but increased by about 10,000 to 170,000. The test is the first solution enabling adequate pyrogen testing of cell therapies, including blood transfusions, and medical devices, but has not been implemented for either application by authorities. As the test can quantitatively assess human-relevant airborne pyrogens, the contribution of pyrogens to chronic obstructive lung diseases and childhood asthma can for the first time be defined and home and workplace safety improved in the future.
Topics: Animal Testing Alternatives; Animals; Drug Contamination; History, 20th Century; History, 21st Century; Humans; Lipopolysaccharides; Monocytes; Pyrogens; Rabbits
PubMed: 25863033
DOI: 10.14573/altex.1503241