Institute for Microbiology, Medical Faculty of Masaryk University  and St. Anna Faculty Hospital in Brno Miroslav Votava, ...
Ability to overcome the defence – A   <ul><li>A) Ability to overcome the  innate  immunity :  </li></ul><ul><li>To  resist...
Ability to resist complement <ul><li>Inhibition of complement activation  </li></ul><ul><li>capsule – shielding surface mo...
http://inst.bact.wisc.edu
Ability to resist phagocytosis – I   <ul><li>1.  N ot to allow being engulfed   </li></ul><ul><li>  inhibitors of   chemot...
http://www.coll-outao.qc.ca
Ability to resist phagocytosis – II  <ul><li>2.  To survive inside the phagocyte </li></ul><ul><li>blockade of phagolysoso...
Ability to overcome the defence  – B <ul><li>B)  Ability to overcome the  acquired  immunity: </li></ul><ul><li>Always an ...
Ability to deceive the immune system – I   <ul><li>To hide itself  in ganglions  (HSV, VZV)  on intracellular membranes  (...
 
Ability to deceive the immune system  – II  <ul><li>3.  To change antigens of one‘s own </li></ul><ul><li>antigenic mimicr...
Ability to deceive the immune system  – III  <ul><li>4.  To suppress immune reaction </li></ul><ul><li>invasion into the i...
Toxicity – I  <ul><li>Damage  by  direct effect of infectious agent  </li></ul><ul><li>Cellular death  lysis by toxins, vi...
Bacterial exotoxins <ul><li>Spreading factors  (hyase, DNase, elastase, collagenase) </li></ul><ul><li>Cytolysins  (lecith...
 
Toxicity – II  <ul><li>Damage  as a  result of  defence  reactions </li></ul><ul><li>a)  Injuries caused  by   inflammator...
 
 
Toxicity – III  <ul><li>Injury as a  result of defence reactions </li></ul><ul><li>b)  Injuries caused  by specific immune...
Recommended reading material   <ul><li>Paul de Kruif: Microbe Hunters </li></ul><ul><li>Paul de Kruif: Men against Death <...
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09 factors of_path_and_virulence_-_2_2_

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09 factors of_path_and_virulence_-_2_2_

  1. 1. Institute for Microbiology, Medical Faculty of Masaryk University and St. Anna Faculty Hospital in Brno Miroslav Votava, Vladana Woznicová FACTORS OF PATHOGENICITY AND VIRULENCE – II Lecture for 2nd-year students April 20 th , 200 9
  2. 2. Ability to overcome the defence – A <ul><li>A) Ability to overcome the innate immunity : </li></ul><ul><li>To resist complement to inhibit complement activation to protect one‘s own surface </li></ul><ul><li>To resist phagocytosis not to allow being engulfed to survive inside the phagocyte </li></ul><ul><li>To interfere with the cytokine function </li></ul>
  3. 3. Ability to resist complement <ul><li>Inhibition of complement activation </li></ul><ul><li>capsule – shielding surface molecules (meningococci, pneumococci) activation inhibitors (gonococci – addition of sialic acid to terminal saccharides , many viruses, E. coli and S. pyogenes – production of regulation factor H, S. pyogenes and P. aeruginosa – enzymes splitting C3b a C5a) </li></ul><ul><li>Protection of the surface (salmonellae and E. coli in S phase, flagella of motile bacteria) </li></ul><ul><li>Ability to resist complement -> s eroresistance </li></ul>
  4. 4. http://inst.bact.wisc.edu
  5. 5. Ability to resist phagocytosis – I <ul><li>1. N ot to allow being engulfed </li></ul><ul><li> inhibitors of chemotaxis (bordetellae, vaginal anaerobes, pseudomonads) </li></ul><ul><li> leucocidins and lecithinase (staphylococci, streptococci, pseudomonads, clostridia) </li></ul><ul><li> injecting Yop (yersiniae) </li></ul><ul><li> formation of capsule ( most importan t! ) </li></ul><ul><li>agents of meningitis and pneumonia ( N. meningitidis, H. influenzae, E. coli, S. pneumoniae, K. pneumoniae ) </li></ul>
  6. 6. http://www.coll-outao.qc.ca
  7. 7. Ability to resist phagocytosis – II <ul><li>2. To survive inside the phagocyte </li></ul><ul><li>blockade of phagolysosome formation ( C hlamydia, M ycobacteri um , L egionella, T oxoplasma ) </li></ul><ul><li>escape from phagosome ( R ickettsia, S higella, L isteria, L eishmania, T rypanosom a ) </li></ul><ul><li>production of antioxidants </li></ul><ul><li>(staphylococci, gonococci, meningococci) </li></ul><ul><li>marked tenacity </li></ul><ul><li>( C oxiell a , E hrlichia ) </li></ul>
  8. 8. Ability to overcome the defence – B <ul><li>B) Ability to overcome the acquired immunity: </li></ul><ul><li>Always an attempt to avoid antibodies or immune lymphocytes : </li></ul><ul><li>to reproduce quickly (respiratory viruses, diarrhoeal agents, malarial plasmodia) </li></ul><ul><li>attempt to deceive immune system </li></ul><ul><li>to hide itself </li></ul><ul><li>to change one‘s own antigens </li></ul><ul><li>to induce tolerance </li></ul><ul><li>attempt to suppress immune reaction </li></ul>
  9. 9. Ability to deceive the immune system – I <ul><li>To hide itself in ganglions (HSV, VZV) on intracellular membranes (HIV, adenov.) in infectious focuses ( M. tbc , echinococci) in privileged sites (agents of mucosal infections, T. gondii in eye, retroviruses in cellular genome) </li></ul><ul><li>2. To induce the immune tolerance </li></ul><ul><li>(CMV, rubella v., leishmaniae, cryptococci, maybe even HIV) </li></ul>
  10. 11. Ability to deceive the immune system – II <ul><li>3. To change antigens of one‘s own </li></ul><ul><li>antigenic mimicry ( S. pyogenes, T. pallidum, M. pneumoniae ) </li></ul><ul><li>antigenic camouflage (schistosomes – blood proteins, staphylococci – protein A, streptococci – protein G, CMV – βmG) </li></ul><ul><li>antigenic variability (trypanosomes, borreliae, gonococci, influenza virus) </li></ul>
  11. 12. Ability to deceive the immune system – III <ul><li>4. To suppress immune reaction </li></ul><ul><li>invasion into the immune system (HIV, m easles virus) interference in cytokine formation ( M. leprae , protozoa) production of superantigens (staphylococci, streptococci) production of proteases (meningococci, gonococci, haemophili, pneumococci) binding Fc fragment of IgG (staphylococci, streptococci, HSV) </li></ul><ul><li>? (influenza virus, HBV, EBV) </li></ul>
  12. 13. Toxicity – I <ul><li>Damage by direct effect of infectious agent </li></ul><ul><li>Cellular death lysis by toxins, viruses, immune lymphocytes apoptosis (HSV, shigellae) </li></ul><ul><li>Metabolic injury – influence of exotoxins </li></ul><ul><li>Mechanical causes (schistosomal eggs, P. jirovecii , pseudomembranes in diphtheria) </li></ul><ul><li>The most frequent cause of death -> septic shock triggered by endotoxins G – : lipopolysaccharide G + : teichoic acid + peptidoglycan </li></ul>
  13. 14. Bacterial exotoxins <ul><li>Spreading factors (hyase, DNase, elastase, collagenase) </li></ul><ul><li>Cytolysins (lecithinase, sfingomyelinase, hemolysins) </li></ul><ul><li>Inhibitors of proteosynthesis (diphtheria toxin) </li></ul><ul><li>Pharmacologically effective toxins (choleragen, E. coli thermolabile enterotoxin, pertussis toxin) </li></ul><ul><li>Neurotoxins (tetanotoxin, botulotoxin) </li></ul><ul><li>Superantigens (staphylococcal enterotoxin and exfoliatin, streptococcal pyrogenic toxin) </li></ul>
  14. 16. Toxicity – II <ul><li>Damage as a result of defence reactions </li></ul><ul><li>a) Injuries caused by inflammatory reaction: calor, rubor, tumor, dolor, functio laesa = typical markers of inflammation = symptoms of disease </li></ul><ul><li>edema : encephalitis, epiglottitis inflammatory infiltrate: pneumonia suppuration: blennorrhoea neonatorum formation of connective tissue: scarring </li></ul>
  15. 19. Toxicity – III <ul><li>Injury as a result of defence reactions </li></ul><ul><li>b) Injuries caused by specific immune reaction (immunopathological consequences of hypersensitivity ) </li></ul><ul><li>1st type: (IgE, anaphylaxis) helminthoses </li></ul><ul><li>2nd type: (cytotoxicity) hepatitis B, febris rheumat. </li></ul><ul><li>3rd type: (immunocomplexes) poststreptococcal nephritis, systemic reactions during sepsis </li></ul><ul><li>4th type: (late, cellular) tbc, lepra, syphilis, actinomycosis, rash in measles </li></ul>
  16. 20. Recommended reading material <ul><li>Paul de Kruif: Microbe Hunters </li></ul><ul><li>Paul de Kruif: Men against Death </li></ul><ul><li>Axel Munthe: The Story of San Michele </li></ul><ul><li>Sinclair Lewis: Arrowsmith </li></ul><ul><li>André Maurois: La vie de Sir Alexander Fleming </li></ul><ul><li>Hans Zinsser: Rats, Lice, and History </li></ul><ul><li>Michael Crichton: Andromeda Strain </li></ul><ul><li>Albert Camus: Peste </li></ul><ul><li>Victor Heisser: An American Doctor Odyssey </li></ul>

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