Disease And Aimmunity Flashcards
o Ability of microbial species to cause a disease
Pathogenicity
o Occurs as the result of interactions between the
pathogen and the host
Infectious disease
o Pathological condition due to the growth of
microorganisms in a host tissues
Infection
o A person or animal with asymptomatic infection
that can be transmitted to another susceptible
person or animal
Carrier
o Process by which bacteria stick to the surfaces of
host cells
o A major initial step in the infection process
Adherence (adhesion, attachment)
o Process whereby bacteria, animal parasites,
fungi, and viruses enter host cells or tissues and
spread in the body
Invasion
o Ability of a microorganism to produce a toxin that
contributes to the development of disease
Toxigenicity
o Quantitative ability of an agent to cause disease
o Involves adherence, invasion, and toxigenicity
Virulence
PORTAL OF ENTRY OF MICROORGANISMS
External and internal surfaces
Skin, conjunctiva
Mucous membrane of respiratory tract and urogenital tract
Intestines
FOR MICROORGANISMS TO CAUSE INFECTION
It must enter the host
Must metabolize and multiply on or in host tissues
Must be able to resist host defenses
Must damage the host
A localized infection with a collection of pus
surrounded by an inflamed area
Abscess
Short, but severe course
Acute
Presence of viable bacteria in the blood
Bacteriacemia
Persists over a long time
Chronic
Subclinical, no symptoms
Covert
Transmitted between hosts infected with
different organisms
Cross
Exist in circumscribed areas
Fecal
Infectious agent multiplies with great intensity
Fulminating
Caused as a result of healthcare
Iatrogenic
Persists in tissues for long periods, during
most of which there are no symptoms
Latent
Restricted to a limited region or to one or
more anatomical areas
Localized
More than one organism present
simultaneously
Mixed
Develops during a stay at the hospital or
other clinical care facility
Nosocomial
Due to an agent that does not harm a
healthy host, but takes advantage of an unhealthy one
Opportunistic
Symptomatic
Overt
Caused by plant pathogens
Phytogenic
First infection that often allows other
organisms to appear on the scene
Primary
Results in pus formation
Pyogenic
Caused by an organism, following an initial
or primary infection
Secondary
The condition resulting from the
presence of bacteria, or their toxins in
blood or tissues; The presence of
pathogens or their toxins in the blood
or other tissues
Sepsis
Blood poisoning associated with persistence
of pathogenic organisms or their toxins in
the blood
Septicemia
Sepsis with hypotension despite adequate fluid resuscitation, along with the presence of perfusion abnormalities that may include, but are not limited to, lactic acidosis, oliguria, or an acute alteration in mental status
Sepetic shock
Sepsis associated with organ dysfunction,
hypoperfusion or hypotension;
Hypoperfusion and perfusion abnormalities
may include, but are not limited to lactic
acidosis, oliguria, or an acute alteration in
mental status
Severe sepsis
Occurs only occasionally
Sporadic
No detectable symptoms or manifestations
Subclinical (inapparen or covert)
Spread throughout the body
Systemic
Condition arising from toxins in the blood
Toxemia
Caused by a parasitic organism that is
normally found in animals other than
humans
Zoonosis
o Attachment of pathogens to the surfaces of the
host (e.g. N. gonorrhoea)
o Some are introduced through vectors
Microbial adherence
Most commonly produced by Gram-positive bacteria
Secreted by living cells
EXOTOXINS
Types of Exo-toxin:
Neurotoxin
Enterotoxin
Cytotoxin
Leukocidin
Hemolysin
affect the nerve tissues
(C. tetani and C. botulinum)
Neurotoxin
Intestine
Cholera toxin caused by V. cholerae
Found in foods and seafoods
Enterotoxin
kills the cells
(Deptheria toxin) (Corynebacterium diptheriae)
Cytotoxin
alpha toxin of S. aureus
Leukocidin
lysis of rbc
(Streptolysin O) (S. pyogenes)
Hemolysin
Found in the cell wall of Gram-negative m.o.
Released upon cell lysis
Endotoxin
Change in body temperature due to the release of pyrogen
Pathogenecity
Mode of Transmission
Airborne (droplets, droplet nuclei, infectious dusts)
Food borne
Water borne
Blood Transfusion
Direct contact with infected individuals
Arthropod borne infection
Ability of the body to overcome and resist infection
A natural or acquired resistance to a specific disease
Immunity
Summation of all naturally occurring defense mechanism
Directed to almost all type of antibodies
NATURAL/ NONSPECIFIC/ INNATE IMMUNITY
Exposure to antigen or antigen is experienced prior to the
development of Antibody
Antibody produced is directed to specific Antigen.
ADAPTIVE/ ACQUIRED/ SPECIFIC IMMUNITY
CELLS OF IMMUNE SYSTEM
Lymphoid cells
Mononuclear cells
Granulocytes
Mast Cells
Dendritic Cells
Where immature lymphocytes mature and differentiate into
B and T lymphocytes
PRIMARY ORGANS AND TISSUES
Where lymphocytes may encounter and binds antigen
SECONDARY ORGANS AND TISSUES
Filtering microorganism and Antigen from tissues
Spleen
Trapping microorganisms and Antigen
from local tissue
Lymph node
Species immunity
Racial immunity
Individual immunity
Genetic
Skin
Mucosal cells
Body temperature
Oxygen tension
o Lungs is favorable for anaerobes
Age
Hormonal balance
o Steroids suppresses immune mechanism
Coughing, sneezing. Perspiring, etc.
Physical or Anatomic Barriers
Substances secreted by the body which protect from
invading pathogens
BIOCHEMICAL (HUMORAL FACTORS)
Present in various body fluids
Lyzozymes (Neuraminidase)
Fe storage protein, competes with
bacteria for Fe
Lactoferrin
Catalyzes the conversion of H2O2 to
water and oxygen
Lactoperoxidase (milk, saliva)
Released by platelets during clot
formation
Betalysine
Attract phagocytes
Chemotactic factors
Produced by the body, directed to all tpes of
microorganisms
SYSTEMIC FACTORS
This are produced by our body that could combat viruses,
even cancer cells and prevent other cells from getting
infected
Interferons
Produced by leukocytes, activates complement by
alternative pathway
Properdin
Chief humoral mediation of Ag-Ab rnx
Complement
Cellular factors
Phagocytotic cells
Mast Cells
Natural Killer Cells
most important phagocytic cells
PMN, monocytes and macrophage
are first to migrate in response to invasion of pathogens
PMNs
Process of phagocytosis
Initiation, Chemotaxis, Engulfment, Digestion, Exocytosis
Formation of cell-surface receptors (Adherence of pathogens)
Initiation Stage
Initiation receptors
FMLR
CR-3
Laminin receptors
Movement of phagocyte towards or away in response to
chemotaxin
Emigration of phagocytes from capillaries
Chemotaxis
Emigration of phagocytes from capillaries
Diapedesis
Attachment of organism to phagocyte (aided by opsonins, CRP, complement component or Ab)
Formation of phagosomes or phagocytic vacoule
Respiratory burst
Engulfment stage
Formation of phagolysosome
Digestion or Cryptopepsis
Generation of bactericidal metabolites resulting to the
killing of pathogens:
Reduction of NADPH
H2O2 production
Hypochlorite and Hydroxyl radicals
Excretion of undigested materials
Excretion or Exocytosis
Antibody-mediated Immunity
Involved the production antibodies from differentiated B lymphocytes
Acquired either in response to infection or through
Immunization/vaccination
Humoral-Mediated Immunity
Lymphocytes are unique bearer of Immunologic specificity
Mediated by the link between T-lymphocytes and
phagocytic cells
CELL-MEDIATED IMMUNITY
Interact with infected host cells through
receptors on T-cell surface
Cytotoxic T cells
Interact with macrophages and secrete cytokines (interleukins) that stimulate TC, TH, and B cell to proliferate
Helper T cells
Shorter latency period due to specific memory cells
developed during the primary I.R.
Secondary immune response
Host is exposed to the antigen for the first time
Primary immune response
Small proteins important in the regulation of growth and
activity of blood cells and cells of the Immune System
Soluble mediators of host defense responses both specific
and non-specific, which involved the elimination of foreign
antigen such as microorganism
Cytokines
Heat-labile component of human plasma that augment
opsonization of bacteria by antibodies
Helps other antibodies that kills bacteria
Mediate Inflammation, activates phagocytic cells
Complement
Draw bacteriolysis
Drawing
The over-all reaction of the body to injury (such as
pathogens and wounds) or invasion by infectious agent
Inflammation
Cardinal signs
Rubor, Tumor, Calor, Dolor,Funtio Laesa
Due to increase blood flow to the inflamed area
Redness (Rubor)
Leakage of plasma to surrounding tissues
Swelling (Tumor)
Due to Interleukin-1 secreted by phagocyte
Heat (Calor)
Due to anaerobic glycolysis occur in phagocytosis
Pain (Dolor)
Result of prolonged Inflammatory process
Lost of function (Functio Laesa)
Stages of Inflammatory Response
Vascular Response
Cellular Response
Cellular Proliferation
immune
responsiveness that may be desirable to the ff:
Hypersensitivity reaction
Auto-immune disease
Prevention of rejection of graft
Surgical manipulation
Physical
Chemical or biological can include
Immunosuppressive drugs
Prophylaxis
Immune response which results in exaggeration/
inappropriate reactions that are harmful to the host
HYPERSENSITIVITY REACTION
Immediate hypersensitivity (occurs within minutes after
contact with the allergen)
IgE (antibody involve)
Histamine is the primary mediator
Type I - Anaphylactic
Antibody dependent
Immunoglobulin is mainly IgG
Type II - Cytotoxic
IgG and IgM combines Ag forming complexes that activates
complement causing:
o Inflammation
o leberation of chemotactic factor,
o release of damaging lysosomal enzymes
TYPE III – IMMUNED TYPE HYPERSENSITIVITY RXN
Delayed Hypersensitivity reaction
No antibody involve
Common:
o Tissue transplantation
o Viral diseases
o Contact dermatitis
TYPE IV – CELL-MEDIATED HYPERSENSITIVITY RXN
ESSENTIAL CHARACTERISTIC OF ACTIVE IMMUNITY
Recognition, Specificity, Memory
Suspension of killed, living or attenuated m.o. used as antigen to produce immunity against infection by a particular microorganism
Vaccine
Made from exotoxins by destroying the poisonous portion with heat, UV light and chemical agents without altering their antigenic specificity
Toxoids
prepared using heat o chemical agents
Killed vaccine
frequent sub-culture on artificial media
Live attenuated
prepared from bacterial structure component
Bacterial material
Usually protein in nature and capable of eliciting the
production of antibody
Antigen
Incomplete antigens
Cannot elicit immune response but can react with specific Ab or block a specific Ag-Ab reaction
Hapten
Substances produced in response to the introduction of an
antigen
Antibody
PARTS OF ANTIBODY
Two heavy chain, to light chain, F Ab fragment, Fc frgament
Neutralizes toxins
Anti-toxins
Clumping of bacterial cells
Agglutins
Precipitation of bacterial cells
Precipitin
Cells lysis
Lysin
Makes the m.o susceptible to phagocytosis
Opsonin
No known antigenic stimulus
Naturally occuring
Produced after stimulation of the immune system
Immuned type