The First Live Attenuated Vaccines

Total Page:16

File Type:pdf, Size:1020Kb

The First Live Attenuated Vaccines MILESTONES MILESTONE 3 The first live attenuated vaccines Awareness of Edward Jenner’s pioneering COVID-19 treatment trials, 24 sheep, 1 Despite failing to culture the rabies-caus- studies of smallpox vaccination (MILESTONE 2) goat and 6 cows were inoculated twice with ing organism outside animal hosts or to view led Louis Pasteur (1822–1895) to propose Pasteur’s anthrax vaccine, on 5 and 17 May it under a microscope (because, unknown to that vaccines could be found for all virulent 1881. A control group of 24 sheep, 1 goat and Pasteur, rabies is caused by a virus rather than diseases. 4 cows remained unvaccinated. On 31 May a bacterium), Pasteur discovered that the Pasteur began to study chicken cholera all the animals were inoculated with freshly virulence of his rabies stocks, maintained by in 1877 and by the following year had suc- isolated anthrax bacilli, and the results were serial intracranial passage in dogs, decreased ceeded in culturing the causative organism, examined on 2 June. All vaccinated animals when the infected material was injected Pasteurella multocida. In 1879, Pasteur into different species. Starting with a highly discovered by chance that cultures of this virulent rabies strain serially passaged many bacterium gradually lost their virulence times in rabbits, Pasteur air-dried sections over time. Before leaving to go on a holiday, of infected rabbit spinal cord to weaken the Pasteur had instructed an assistant to inject virus through oxygen exposure, as explained the latest batch of chickens with fresh cultures in Pasteur’s 26 October 1885 report to the of P. multocida. The assistant forgot to do this, French Academy of Science. All 50 dogs however, and then himself went on holiday. vaccinated with this material by Pasteur were On his return, Pasteur’s assistant inoculated successfully protected from rabies infection, the chickens with the cultures, which by this although we now understand attenuation to time had been left in the laboratory for a result from viral passage through dissimilar month, stoppered only with a cotton-wool species, rather than air exposure. plug. The inoculated chickens developed mild Up to this point, however, Pasteur had symptoms but recovered fully. no proof that his vaccines, a term coined by Another scientist might have concluded Pasteur to honour Jenner’s work, would be that the cultures had (mostly) died, but effective in humans. Reluctantly — as Pasteur Pasteur was intrigued. He injected the recov- was not a licensed physician and could have ered chickens with freshly cultured cholera been prosecuted for doing so — on 6 July bacteria. When the birds remained healthy, 1885, Pasteur used his rabies vaccine, in the Pasteur reasoned that exposure to oxygen presence of two local doctors, to treat 9-year- had caused the loss of virulence. He found old Joseph Meister, who had been severely that sealed bacterial cultures maintained their bitten by a neighbour’s rabid dog. Joseph virulence, whereas those exposed to air for Meister received a total of 13 inoculations differing periods of time before inoculation over a period of 11 days, and survived in showed a predictable decline in virulence. good health. Pasteur’s reluctance might also He named this progressive loss of virulence be accounted for by posthumous analysis of ‘attenuation’, a term still in use today. Louis Pasteur holding rabbits, which were used to help his laboratory notebooks, which revealed that Pasteur, along with Charles Chamberland develop the vaccine for rabies. Credit: World History Archive / Pasteur had vaccinated two other individuals and Emile Roux, went on to develop a live Alamy Stock Photo before Meister; one remained well but might attenuated vaccine for anthrax. Unlike not actually have been exposed, and the other cultures of the chicken cholera bacterium, remained healthy. The unvaccinated sheep and developed rabies and died. Bacillus anthracis cultures exposed to air read- goats had all died by the end of the day, and all By the end of 1885, several more desperate ily formed spores that remained highly viru- the unvaccinated cows were showing anthrax rabies-exposed people had travelled to lent irrespective of culture duration; indeed, symptoms. Chamberland’s private laboratory Pasteur’s laboratory to be vaccinated. During Pasteur reported that anthrax spores isolated notebooks, however, showed that the anthrax 1886, Pasteur treated 350 people with his from soil where animals that died of anthrax vaccine used in these public experiments had rabies vaccine, of whom only one developed had been buried 12 years previously remained actually been attenuated by potassium dichro- rabies. The startling success of these vaccines as virulent as fresh cultures. However, Pasteur mate, using a process similar to that developed led directly to the founding of the first discovered that anthrax cultures would by Pasteur’s competitor, Jean Joseph Henri Pasteur Institute in 1888. grow readily at a temperature of 42–43 °C Toussaint. Caroline Barranco, but were then unable to form spores. These In 1881, Victor Galtier (who had already Nature Reviews Cross-Journal Team non-sporulating cultures could be maintained demonstrated transmission of rabies from at 42–43 °C for 4–6 weeks but exhibited a dogs to rabbits) reported that sheep injected ORIGINAL ARTICLES Pasteur, L. An address on vaccination in marked decline in virulence over this period with saliva from rabid dogs were protected relation to chicken cholera and splenic fever. Br. Med. J. 2, 283–284 (1881) | Pasteur. L. Méthode pour prévenir la rage when inoculated into animals. from subsequent inoculations. These surpris- après morsure. C. R. Séances Acad. Sci. (Séance du lundi 26 Accordingly, in public experiments at ing observations piqued Pasteur’s interest and octobre 1885) Pouilly-le-Fort, France, conducted under a he went on to develop the first live attenuated FURTHER READING Jackson, A. C. (ed.) Rabies: Scientific Basis of the Disease and Its Management (Academic Press, 2013) media spotlight reminiscent of that on today’s rabies vaccine. NATURE MILESTONES | VACCINES NOVEMBER 2020 | S7.
Recommended publications
  • Information and Communication Guide on Vaccines
    Module 2 EUROPEAN NURSE Information and Communication Guide ON VACCINES The European Specialist Nurses Organisation (ESNO) is a non-profit organisation with the goal to facilitate and provide an effective framework for communication and co-operation between the European Specialist Nurses Organisations and its constituent members. ESNO represents the mutual interests and benefits of these organisations to the wider European community in the interest of the public health. Members of ESNO consist of individual European specialist nurses member organizations and associates, both institutional and individual. The organisation focusses on enhancing the capacity and capability of specialists nurses to deliver hight quality healthcare by raising and harmonise specialist nursing education standards and actively contribute to health themes and threats, providing the best possible expertise, both national and in European cross border context. A publication from the European Specialist Nurses Organisation April 2021 - www.esno.org Copyright: ©2021 European Specialist Nurses Organisation. All rights reserved. No part of this publication may be reproduced, distributed, or transmitted in any form or by any means, including photocopying, recording, or other electronic or mechanical methods, without the prior written permission of the publisher, except in the case of brief quotations embodied in critical reviews and certain other noncommercial uses permitted by copyright law. CONTENTS Vaccination 1 Introduction 5 2 Principles of vaccination 6 2.1 Principle
    [Show full text]
  • The Spontaneous Generation Controversy (340 BCE–1870 CE)
    270 4. Abstraction and Unification ∗ ∗ ∗ “O`uen ˆetes-vous? Que faites-vous? Il faut travailler” (on his death-bed, to his devoted pupils, watching over him). The Spontaneous Generation Controversy (340 BCE–1870 CE) “Omne vivium ex Vivo.” (Latin proverb) Although the theory of spontaneous generation (abiogenesis) can be traced back at least to the Ionian school (600 B.C.), it was Aristotle (384-322 B.C.) who presented the most complete arguments for and the clearest statement of this theory. In his “On the Origin of Animals”, Aristotle states not only that animals originate from other similar animals, but also that living things do arise and always have arisen from lifeless matter. Aristotle’s theory of sponta- neous generation was adopted by the Romans and Neo-Platonic philosophers and, through them, by the early fathers of the Christian Church. With only minor modifications, these philosophers’ ideas on the origin of life, supported by the full force of Christian dogma, dominated the mind of mankind for more that 2000 years. According to this theory, a great variety of organisms could arise from lifeless matter. For example, worms, fireflies, and other insects arose from morning dew or from decaying slime and manure, and earthworms originated from soil, rainwater, and humus. Even higher forms of life could originate spontaneously according to Aristotle. Eels and other kinds of fish came from the wet ooze, sand, slime, and rotting seaweed; frogs and salamanders came from slime. 1846 CE 271 Rather than examining the claims of spontaneous generation more closely, Aristotle’s followers concerned themselves with the production of even more remarkable recipes.
    [Show full text]
  • Vaccines 101 the Very Last Day That I Was a Pediatric Resident. Um, Many
    Vaccines 101 The very last day that I was a pediatric resident. Um, many years ago, a toddler walked into the emergency room and uh, and progressively got sicker and sicker. That's Dr. Katherine Edwards, a world expert in pediatric infectious disease in vaccinology. She's also a professor of pediatrics at Vanderbilt university and she's been working on vaccines for 40 years. I did a spinal tap on her and realized that she had Haemophilus influenza, typ e B meningitis, Haemophilus influenza, type B or HIB is it bacteria normally found in our nose and throat that can lead to very serious life threatening infections and no matter what I did in that day and into the night in terms of prompt antibiotics and she'd just been sick a few hours and, and fluids and all the, you know, ventilators and all the best things that modern medicine, she died, the vaccine for hip was not available until the 1990s. And until it did become available, hip disease affected approximately 25,000 children each year with things like meningitis, pneumonia, and bloodstream infections. And at that time in the hospital that I was practicing at any one time, there were generally five or six patients that had Haemophilus meningitis or invasive disease or some complication of this particular infection. And we knew that from the basic science that if you had antibody to the capsule or to the coat of the organism, that you were protected from disease. But we really didn't know how to make little kids make antibody.
    [Show full text]
  • Bcch 2019-20 Flu Vaccine – Oncology Clinic
    BCCH 2019-20 FLU VACCINE – ONCOLOGY CLINIC We are providing influenza vaccines for patients who are on therapy and have platelets > 50,000 and ANC over 0.5 (and expected to stay above 0.5 for the next 48 hours, in order to minimize risk of admission in case of fever). Please do not schedule appointments for flu shots only. Please advise the family that immunization of all family members is recommended. The Oncology Outpatient Clinic is not providing immunizations for family members or for those patients who are OFF therapy. Flu shots can be given by family doctors to patients and their families, or they can get a flu shot at the BCCH drop-in Family Immunization clinic in the Ambulatory Care Building, across from the Ambulatory Care Pharmacy on week days in the fall months. Pediatric oncology patients can also get a flu shot at almost any community pharmacy at no cost as they are considered “at risk.” Age Dose** Doses required 6 months – 9 years 0.5 mL IM 1 or 2* > 9 years 0.5 mL IM 1 Less than 6 months Not recommended *Two doses administered at least 4 weeks apart are recommended for children under 9 years of age who are receiving influenza vaccine for the first time. **The recommended site of vaccination is the deltoid muscle for adults and older children. The preferred site for infants and young children is the anterolateral aspect of the thigh. Contraindications: • Febrile illness • Thimerosal sensitivity Special considerations: • Egg allergic individuals (including those who have experienced anaphylaxis following egg ingestion) can be immunized with inactivated influenza vaccine (such as Flulaval tetra) • Thimerosal allergic patients should be vaccinated using Agriflu which can be obtained from local public health units, (but not in the oncology clinic).
    [Show full text]
  • HIV Vaccine Development Dr. Patricia Fast 1
    HIV Vaccine Development Dr. Patricia Fast HIV Vaccine Development Dr. Patricia Fast (MD, PhD) Senior Technical Advisor, International AIDS Vaccine Initiative Adjunct Clinical Associate Professor, Infectious Disease, Pediatrics Stanford University School of Medicine How It Began 1984 • Human Immunodeficiency Virus (HIV-1) discovered as the cause of AIDS • Prediction: a vaccine will soon be developed! Non-Human Primate Models Focusing on this dominant model • Simian Immunodeficiency Virus (SIV) lead to a bias – SIV Mac 239 causes AIDS-like disease in Macaques almost impossible to neutralize • SHIV hybrid (with HIV Envelope) allows research into neutralizing antibodies in macaques • Chimpanzees can be infected by HIV, but seldom get AIDS False starts • Traditional vaccine approaches fail in NHP model . Killed SIV does not really protect against SIV o Initial positive result was an artifact . Live attenuated SIV protects, but is not safe o Attenuated vaccine was shown to regain virulence The screen versions of these slides have full details of copyright and acknowledgements 1 HIV Vaccine Development Dr. Patricia Fast How would an AIDS vaccine work? A note about virus biology • HIV has many mechanisms to escape immune recognition e.g. : . Rapid formation of variation . Structural aspects How would an AIDS vaccine work? Immune Mechanisms • T cells . Kill virus-infected cells . Slow down or stop replication of viruses within cells . Can directly kill virus infected cells . Secrete substances that block viral replication Can neutralize virus when they prevent entry; by binding viral envelope protein or the cellular receptors HIV is extremely variable Europe and North America East Africa Southern Africa, India and China Part of an HIV phylogenetic tree The screen versions of these slides have full details of copyright and acknowledgements 2 HIV Vaccine Development Dr.
    [Show full text]
  • Redalyc.Joseph Achille Le Bel. His Life and Works
    Revista CENIC. Ciencias Químicas ISSN: 1015-8553 [email protected] Centro Nacional de Investigaciones Científicas Cuba Wisniak, Jaime Joseph Achille Le Bel. His Life and Works Revista CENIC. Ciencias Químicas, vol. 33, núm. 1, enero-abril, 2002, pp. 35-43 Centro Nacional de Investigaciones Científicas La Habana, Cuba Available in: http://www.redalyc.org/articulo.oa?id=181625999008 How to cite Complete issue Scientific Information System More information about this article Network of Scientific Journals from Latin America, the Caribbean, Spain and Portugal Journal's homepage in redalyc.org Non-profit academic project, developed under the open access initiative Revista CENIC Ciencias Químicas, Vol. 33, No. 1, 2002. RESEÑA BIOGRAFICA Joseph Achille Le Bel. His Life and Works Jaime Wisniak Department of Chemical Engineering, Ben-Gurion University of the Negev, Beer-Sheva, Israel 84105. [email protected]. Recibido: 26 de abril del 2001. Aceptado: 22 de mayo del 2001. Palabras clave: Le Bel, Química, estereoquímica, actividad óptica, cosmogonia Key words: Le Bel, Chemistry, stereoquímica, optical activity, cosmogony. RESUMEN. Joseph Achille Le Bel es un ejemplo de científicos como Réaumur The same year his father passed que investigaron muchÍsimos temas, pero solo son recordados por uno. Le Bel away and his two sisters, Marie and es un nombre bien conocido por los estudiantes de Química en general, y Emma, took charge of the family in- estereoquímica en particular. El nos dejo los principios básicos que determinan dustry and in this way allowed Le las condiciones geométricas que un compuesto de carbón debe satisfacer para Bel to continue chemical studies.
    [Show full text]
  • Chemists and the School of Nature Bernadette Bensaude Vincent, Yves Bouligand, Hervé Arribart, Clément Sanchez
    Chemists and the School of nature Bernadette Bensaude Vincent, Yves Bouligand, Hervé Arribart, Clément Sanchez To cite this version: Bernadette Bensaude Vincent, Yves Bouligand, Hervé Arribart, Clément Sanchez. Chemists and the School of nature. Central European Journal of Chemistry, Springer Verlag, 2002, pp.1-5. hal- 00937207 HAL Id: hal-00937207 https://hal-paris1.archives-ouvertes.fr/hal-00937207 Submitted on 30 Jan 2014 HAL is a multi-disciplinary open access L’archive ouverte pluridisciplinaire HAL, est archive for the deposit and dissemination of sci- destinée au dépôt et à la diffusion de documents entific research documents, whether they are pub- scientifiques de niveau recherche, publiés ou non, lished or not. The documents may come from émanant des établissements d’enseignement et de teaching and research institutions in France or recherche français ou étrangers, des laboratoires abroad, or from public or private research centers. publics ou privés. Chemists and the school of nature B. Bensaude Vincent, Arribart, H., Bouligand, Y, Sanchez C.), New Journal of Chemistry, 26 (2002) 1-5. The term biomimicry first appeared in 1962 as a generic term including both cybernetics and bionics1. It referred to all sorts of imitation of one form of life by another one while the term "bionics" defined as "an attempt to understand sufficiently well the tricks that nature actually uses to solve her problems"2 is closer to the meaning of "biomimicry" as it has been used by material scientists since the 1980s. Biomimetism is an umbrella covering a variety of research fields ranging from the chemistry of natural products to nanocomposites, via biomaterials and supramolecular chemistry.
    [Show full text]
  • Producing, Controlling and Stabilizing Pasteur's Anthrax Vaccine
    Producing, Controlling and Stabilizing Pasteur’s Anthrax Vaccine: Creating a New Industry and a Health Market Maurice Cassier To cite this version: Maurice Cassier. Producing, Controlling and Stabilizing Pasteur’s Anthrax Vaccine: Creating a New Industry and a Health Market. Science in Context, Cambridge University Press (CUP), 2008. halshs- 01894157 HAL Id: halshs-01894157 https://halshs.archives-ouvertes.fr/halshs-01894157 Submitted on 23 Dec 2018 HAL is a multi-disciplinary open access L’archive ouverte pluridisciplinaire HAL, est archive for the deposit and dissemination of sci- destinée au dépôt et à la diffusion de documents entific research documents, whether they are pub- scientifiques de niveau recherche, publiés ou non, lished or not. The documents may come from émanant des établissements d’enseignement et de teaching and research institutions in France or recherche français ou étrangers, des laboratoires abroad, or from public or private research centers. publics ou privés. Vol. 21, No. 2 Producing, Controlling and Stabilizing Pasteur’s Anthrax Vaccine: Creating a New Industry and a Health Market Maurice Cassier CNRS Argument When Pasteur and Chamberland hastily set up their small biological industry to meet the agricultural demand for the anthrax vaccine, their methods for preparation and production had not yet been stabilized. The process of learning how to standardize biological products was accelerated in 1882 when vaccination accidents required the revision of production norms as the first hypotheses on fixity, inalterability, and transportability of vaccines were invalidated and replaced by procedures for continuous monitoring of the calibration of vaccines and the renewal of vaccine strains. Initially, the incompleteness and ongoing development of production standards justified Pasteur’s monopoly on the production of the anthrax vaccine under his immediate supervision.
    [Show full text]
  • Humanized Mice for Live-Attenuated Vaccine Research: from Unmet Potential to New Promises
    Review Humanized Mice for Live-Attenuated Vaccine Research: From Unmet Potential to New Promises Aoife K. O’Connell and Florian Douam * Department of Microbiology, National Emerging Infectious Diseases Laboratories, Boston University School of Medicine, Boston, MA 02118, USA; [email protected] * Correspondence: [email protected] Received: 21 December 2019; Accepted: 13 January 2020; Published: 21 January 2020 Abstract: Live-attenuated vaccines (LAV) represent one of the most important medical innovations in human history. In the past three centuries, LAV have saved hundreds of millions of lives, and will continue to do so for many decades to come. Interestingly, the most successful LAVs, such as the smallpox vaccine, the measles vaccine, and the yellow fever vaccine, have been isolated and/or developed in a purely empirical manner without any understanding of the immunological mechanisms they trigger. Today, the mechanisms governing potent LAV immunogenicity and long-term induced protective immunity continue to be elusive, and therefore hamper the rational design of innovative vaccine strategies. A serious roadblock to understanding LAV-induced immunity has been the lack of suitable and cost-effective animal models that can accurately mimic human immune responses. In the last two decades, human-immune system mice (HIS mice), i.e., mice engrafted with components of the human immune system, have been instrumental in investigating the life-cycle and immune responses to multiple human-tropic pathogens. However, their use in LAV research has remained limited. Here, we discuss the strong potential of LAVs as tools to enhance our understanding of human immunity and review the past, current and future contributions of HIS mice to this endeavor.
    [Show full text]
  • Influenza Whoinsert Generic Name As on 080710
    capacity. Healthcare providers need to assess the benefit and potential risks of administering the vaccine to pregnant women. It is not known whether Influenza Vaccine(Human,Live Attenuated) is excreted in human milk. Therefore, as some viruses are Influenza Vaccine excreted in human milk and additionally, because of the possibility of shedding of vaccine virus and the close proximity of a nursing infant and mother, caution should be exercised if Influenza Vaccine(Human,Live Attenuated) is administered to nursing Sii mothers. (Human, Live Attenuated) Effects on ability to drive and use machines The vaccine is unlikely to produce an effect on the ability to drive and use machines. Pandemic (H1N1) (Freeze-Dried) ADVERSE REACTIONS In clinical trials a few local and systemic reaction were observed. They were mild to moderate in severity and resolved without DESCRIPTION any sequelae. Influenza Vaccine(Human,Live Attenuated) Pandemic (H1N1), freeze dried is a live monovalent vaccine for administration by Local : Nasal discomfort, stuffy nose, sneezing, runny nose, loss of smell red eyes, lacrimation, facial swelling. intranasal spray. The influenza vaccine contains Influenza virus cultivated on embryonated eggs. Systemic : Headache, fatigue, myalgia, arthralgia, irritability, loss of appetite, sore throat, cough, diarrhoea. The incidence was similar in both the study groups. COMPOSITION There were a few unsolicited event reported in both the groups and none of them were causally related to study vaccines. [Propagated in Embryonated hen eggs (SPF)] Each single dose of 0.5 ml contains: 7 OVERDOSE A/17/California/2009/38 > 10 EID50 No case of overdose has been reported. Gelatin (Partially hydrolyzed) 2.5%, Sorbitol 5%, L-Alanine 0.1% L-Histidine 0.21%, Tricine 0.3%, L-Arginine hydrochloride 1.6% Lactalbumin hydrolysate 0.35%, Phosphate buffer saline Base PHARMACOLOGICAL PROPERTIES Reconstitute with Sterile Water for Inhalation USP.
    [Show full text]
  • Cell Theory the CELL THEORY GREW out of the WORK of MANY SCIENTISTS and IMPROVEMENTS in the MICROSCOPE
    Cell Theory THE CELL THEORY GREW OUT OF THE WORK OF MANY SCIENTISTS AND IMPROVEMENTS IN THE MICROSCOPE. Many scientists contributed to the cell theory. ROBERT HOOKE He was the first person to look at cells and named them. He looked at cork cells which are not living. It is the bark of a tree so they are dead plant cells. They are small squares and they reminded him of the small rooms in a monastery called cells ANTON VAN LEEUWENHOEK Credited with improving the microscope. (Zacharias Janssen is credited with discovering/creating microscope). Leeuwenhoek’s microscope could magnify 200x the human eye! Today’s microscopes can magnify up to 1500! MATTHIAS SCHLEIDEN was a German botanist (scientist who studies plants.) He found that the plant parts he examined were made of cells. He made the generalization that all plants were made of cells. THEODOR SCHWANN Studied animals. His microscopic investigations of animal parts led him to generalize that all animals are made of cells After looking at Schleiden’s work ,he further proposed that all organisms are made of cells. RUDOLF VIRCHOW- OMNIS CELLULA C CELLULA”: ALL CELLS FROM CELLS (1855) German doctor that said that new plant cells arise only from existing plant cells, and new animal cells arise only from existing animal cells. Building off the work of Redi (1668) who disproved the idea of spontaneous generation in his experiments about rotting meat. LOUIS PASTEUR-GERM THEORY 1856-Used the microscope to discover that tiny, one- celled (eukaryotic) yeast created alcoholic fermentation and that other one-celled, rod-shaped organisms (prokaryotic bacteria) caused beverages to spoil.
    [Show full text]
  • Pasteur Part II-022514
    What is Life? The Passionate Dedication of Louis Pasteur Part II by Denise Bouchard Ham and Roger Ham The Extraordinary Years of Discovery Louis Pasteur ~1880 Despite a near-fatal stroke in 1868 at the age of 45, which left his left side paralyzed, Pasteur’s greatest achievements lay before him. The power of his insights into the nature of germs and disease exploded. His laboratory was buzzing with activity, and the breakthroughs were only limited by the time and energy required to find a solution to each new disease tackled. Between 1877 and 1888, Pasteur discovered the existence of six different species of pathogenic microbes in humans and animals: septic Vibrio (septicemia), Staphylococcus , Streptococcus , bacillus of chicken cholera, swine fever, and Pneumococcus . “We must find out how to immunize against the diseases for which we have isolated the virus. Just as one can protect man from smallpox, why shouldn't we protect him from other epidemic diseases?” — L. Pasteur 1 THE IDEA OF VACCINATION The idea of using a small dose of something harmful to develop a resistance to it was known for centuries. The advent of the microscope and germ theory opened the door to new potentials in meeting the challenge: how to deliberately expose a person to a dangerous disease without killing them. Mithridates VI, the King of Pontus (the Black Sea area and present-day Turkey), lived from 134-63 B.C. and was known to drink various potions containing small doses of poisons to develop a tolerance. The word Mithridatism refers to this partial immunity.
    [Show full text]