Branches of Microbiology

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• Branches of Microbiology
• Bacteriology
• Virology
• Mycology
• Parasitology
• Immunology
• Recombinant DNA technology

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• Vaccines Vaccination
• Vaccines are products produced from
  microorganisms
• when introduced into a host
• stimulate immune system
• defense against particular microbial disease

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Immunology

• Is a science dealing with immunity
• Immunity the bodys defense against particular
  pathogenic microorganism
• Or
• the ability to wardoff disease through body
  defenses
• Susceptibility lack of immunity

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Immunology

• Immune system is a set of mechanisms that
  protect an individual from infection , by
  recognizing, killing, eliminating foreign
  pathogens or particle
• Antigen(Ag) any substance that causes antibody
  formation (immunogen)
• Antibody(Ab) a protein produced by the body in
  response to an Ag capable of combining
  specifically with that Ag

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Immunology

• There are two types of immunity
• Innate immunity (non specific) an individual
  genetically predetermined resistance to certain
  disease
• Adaptive immunity (specific) immunity obtained
  during the life to produce specific response

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Innate immunity

• Defenses that are present at birth
• The are always present available to provide
  rapid responses to protect us against diseases
• First line
• Second line

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Innate immunity

• Two components
• First line of defense

skin mucous membrane
normal microbiota
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Innate immunity

• Second line of defense

phagocytosis
inflammation
fever
Antimicrobial substances
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Innate immunityfirst line of defenses

• Skin mucous membranes

Physical factors barriers to entry or
processes that remove microbes from the body
surface
Chemical factors substances made by the body
that inhibit microbial growth or destroy them
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The Bodys Surfaces(from a microbes persepctive)
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First line of defensesskin mucous membrane
/Physical factors

• The skin is the most difficult surface to
  penetrate.
• some microbes can penetrate mucous membranes
  but--------
• Saliva ----- washes microbes
• Respiratory tract ciliary action remove microbes
  ---coughing sneezing

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First line of defensesskin mucous membrane /
Chemical factors

• Oil glands of skin ---- inhibit the growth of
  microbes
• Perspiration --- washes microbes
• Lysozyme (tears, nasal secretions,
  perspiration)
• High acidity of gastric juice inhibit microbial
  growth in stomach

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First line of defenses Normal microbiota

• Change the environment prevent the growth of
  pathogens
• competing for essential nutrients
• production of inhibitory substances that
  suppress the growth of potential pathogen

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First-Line Defense
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Second line of defenses

• If a microbe penetrates the first line of defense

phagocytosis
inflammation
fever
Antimicrobial substances
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Second line of defenses

• Phagocytes a cell capable of engulfing
  digesting particles that are harmful to the body
• Phagocytosis the ingestion of microorganisms by
  a cell

phagocytosis
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Second line of defenses Phagocytosis

• Phagocytes WBC (granulocytes, lymphocytes,
  monocytes)
• granulocytes ( neutrophils, basophils,
  eosinophils)

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Leukocytes White Blood Cells
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Phagocytic Leukocytes
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The mechanism of phagocytosis
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Second line of defenses Phagocytosis

• The mechanism of phagocytosis
• 1 the phagocytes are attracted to microorganism
• 2then adheres to microorganism
• the adherence may be facilitated by
  Opsonization ( coating the microorganism with
  serum proteins opsonins

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Second line of defenses Phagocytosis

• 3 pseudopods of the phagocytes engulf the
  microorganism enclose it in a phagocytic
  vesicle
• 4 the microorganisms are killed by lysosomal
  enzyme oxidizing agent inside the phagocytes

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Second line of defensesinflammation

• a host response to tissue damage
  characterized by redness, pain, heat, swelling,
  some time loss of function

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Inflammation
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Inflammation
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Inflammation

• Inflammation gives rise to localized reddening,
  swelling, increased temperatures, and pain.
• The function of inflammation is to localize
  tissue damage, localize responses, and then to
  restore tissue function.
• The action of localized leukocytes is enhanced
  via the attraction of neutrophils and monocytes
  normally found in circulation.
• Microbial materials such as LPS, flagellin
  (making up bacterial flagella), and even
  bacterial DNA serve as indicators of infection
  which in turn activates the production of
  pro-inflammatory cytokines ( immune-system
  activating chemicals).
• In addition to the cell-to-cell interactions
  underlying inflammation, the inflammatory
  response involves localized increases in blood
  flow, leakage of blood vessels, and attraction of
  leukocytes from the blood.

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Second line of defensesfever

• is an abnormally high temperature produced in
  response to a bacterial or viral infection
• fever is considered a defense against disease

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Second line of defensesfever

• High body temp.
• intensifies the effect of antiviral interferon
  
• increases production of transferrins that
  decrease the iron available to microbes
• Also high temp.
• speeds up the body's reaction it may help body
  tissue repair them self's more quickly
• Ab. production have been shown to be enhanced
  at elevated temp.

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Second line of defensesantimicrobial substances

• the body produce certain antimicrobial
  substances that lyse microorganism
• the most important of these are the protein
  of the

Complement system
interferon
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Interferon An Antiviral
dsRNA normally is not present in cells.
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Complement system

• it is a group of steps which composes a large
  number of components
• serum proteins which activated each other in a
  sub sequential manner)
• to produce a specified action
  
• destroy invading microorganism

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complement
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Toll-Like Receptors
Including phagocyte-attracting cytokines.
Danger, Im infected! signal.
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Complement
2. Complement proteins are activated by various
mechanisms.
1. Inactive complement proteins are in constant
circulation.
3. These are the consequences...
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Adaptive immunity

• Obtained during the life of the individual to
  produce specific response
• particular pathogen antigen
• it takes time in days
• cell-mediated humoral components
• exposure leads to immunological memory
• lymphocytes, antigen-specific receptors
  antibodies

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Adaptive immunity

• Cell-mediated response (immunity)
• Is based on T-cells (type of lymphocytes)
• Humoral response (immunity)
• Is based on antibodies

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Adaptive immunity

• Antigen (Ag) immunogen
• Ags are the foreign particles which stimulate
  the immune system to secrete antibodies
• When Ag is introduced into the host, host cell
  induces the formation of specific antibody
  T-lymphocytes that are reactive against the Ag
  (bacteria, viruses, pollen grains, dust..)

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Adaptive immunity

• Immunogenicity
• Is the ability to induce a humoral cell
  mediated immune responses

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Adaptive immunity

• Antibody (Ab)
• Abs are proteins present on the surface of
  B-cells secreted by plasma cells
• circulate in the blood where they search kill
  the microbes
• Abs reside on the serum

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Adaptive immunity
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Adaptive immunity

• each Ab molecule consists of 4 peptides
  chains-----2 identical heavy chains
• -----2 identical light chains
• binds with disulphide bond
• The first a.a of both chains are highly variable
  from which it binds with the Ag

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Adaptive immunity

• Immunoglobulin classes
• 5 classes based on the structure of their heavy
  chain constant region
• IgG
• IgM
• IgA
• IgE
• IgD

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Adaptive immunity
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• IgG Is the most abundant class
• Has the ability to cross the placenta (
  provides a major line of defense against
  infection for the newborn)
• complement activator
• bind on phagocyte mediate
  opsonization
• neutralization of bacterial toxins

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• IgM the first immunoglobulin class produced in
  a primary infection or primary response
• is the first immunoglobulin to be synthesizes
  by the neonate

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• IgA it is the predominant immunoglobulin
  class in external secretion (saliva, tears,
  breast milk mucus of the bronchial,
  genitourinary digestive tract)
• it protect the external surfaces of the body
  from microbial attack ( prevent the adherence of
  microorganism to the surface of mucosal cells)

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• IgE bind to mast cells basophiles
• degranulation
• Histamine
• Hay fever asthma

immediate hypersensitivity
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hypersensitivity
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• IgD involved with the differentiation of
  B-cells where it seems to be interacting with Ag

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Adaptive immunity

• Active immunitydeveloped after Ag enter the body
  the immune system responds with Abs long
  lasting protection
• or
• Passive immunitydeveloped when Ab enter the body
  from an outside source short lived protection

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Passive immunity

• Naturally acquired passive immunity
  (immunoglobulin transferred from mother to baby
  to protect the fetus
• Or
• Artificially acquired passive immunity (direct
  artificial injection of Ab into the host)
• Hepatitis Ig, serum containing antitoxin (tetanus)

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Adaptive immunity

• Active immunity
• Naturally acquired active immunity (follows a
  short time illness)
• )
• Or
• Artificially acquired active immunity
  (vaccination)

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Active immunity
illness

• vaccination

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Active immunity

• memory cells in the lymphoid tissues are
  responsible for producing Ab ,the cells remain
  active for many years produce IgG immediately
  after Ag entry (secondary immune response

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Adaptive immunity

• Humoral immunity (response)
• Is based on antibodies
• Cell-mediated immunity(response)
• Is based on T-cells (type of lymphocytes)

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Humoral response

• Abs bind to the Ag facilitate their elimination
  
• forming clusters ingested by
  phagocytes
• binding of Ab to m.o. can activate complement
  system lyses of m.o.
• Ab bind to toxins or viruses
  prevent their binding to host cell
  (neutralization)

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Cell-mediated response

• Based on T-cells type of lymphocytes
• T-cells are of 2 types
• T-helper
• T-cytotoxic

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Cell-mediated response

• When T-h interact with Ag molecule it becomes
  activated begins to secrete cytokines
  activate B-cells Ab
• activate phagocytes
  kill
• activate T-c
  kill cells that display pathogen (virus)

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• Autoimmunity
• Results from a loss of self-tolerance
• The ability of a host to recognize not make
  Abs against self

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• Immune diseases damage to ones own organs due
  to action of the immune system
• Rheumatoid arthritis IgG, IgM complement
• deposited in joints severe
  pain
• Insulin dependent diabetes mellitus destruction
  of insulin-secreting cells of the
  pancreascell-mediated autoimmune reaction

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• Immunodeficiency the absence of an adequate
  immune response
• Congenital inherited
• Or
• Acquired drugs , cancers , infectious disease
• 
  AIDS

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• vaccination
• immunization
• the process of conferring immunity by
  administering a vaccine

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• Vaccines
• are preparations of killed , inactivated or
  attenuated m.o or toxoids to induce artificially
  acquired active immunity
• Are the safest most effective means of
  controlling infectious diseases

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The effects of vaccination

• The response of the body to the first contact
  with an Ag is called the primary response , it is
  characterized by the appearance of IgM followed
  by IgG
• Subsequent contact with the same Ag results in a
  very high Ab titer called the secondary or
  memory response , the Ab is primarily IgG

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• Attenuated ( living but weakened microbes)
• Long life immunity
• Humeral cell mediated response
• Reversion to virulence
• Inactivated (killed microbes)
• Short life immunity
• Antibody only
• Not reverse to virulance

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• Subunit (antigenic fragments of microbes)
• Subunit
• Recombinant vaccines
• a cellular vaccines disrupted bacterial
  cell

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Vaccination program
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6y. 18-24 m 12m 10m 120d 90d. 60d. 1m
BCG
DT DTP
OPV OPV OPV OPV OPV IPV IPV Polio.v
HiB
HBV
Measles
MMR
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Polio vaccines

• IPV inactivated polio vaccine (killed)
• injection
• OPV attenuated polio vaccine
• orally
• intestine

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• HiB Haemophilus influenzae B
• injection
• DTP combination vaccines
• diphtheria
• tetanus
• pertusis
• injection
• HiB DTP combination

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• HBV hepatitis virus type B HBV surface
  antigen biotechnology
• BCG tuberculosis
• Bacillus Calmett-Guerin
• MMR measles virus mumps virus rubella
  virus

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• Other vaccines
• Pox virus
• Cholera
• Chicken pox
• Influenza virus
• Endemic area
• Travelling to endemic area

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• vaccines should not given to pregnant women
• illness
• immunocompromized individuals

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• Booster to increase the power of
  effectiveness
• Booster dose active immunizing agent usually
  smaller than the initial dose given to maintain
  immunity

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Final Exam

• Good Luck