Immune Defense Against Bacterial Infections Lec Flashcards
are involved in
protecting the body against foreign materials, including
Bacteria.
Both innate and adaptive immunity
Innate immunity is also known as
Natural immunity
a nonspecific
immunity (naturally occurring) wherein it has a
standardized response to all antigens. It lacks
memory.
Innate immunity
Innate immunity Common examples are
exogenous and
endogenous materials
Defense mechanism against invading
microorganisms
Physical barriers
Physical barriers The portal of entry of the microorganisms are
the
Mucus membrane
serves as our physical barriers to that
particular invading microorganism
Skin
is the hydrochloric acid
within our stomach that serves as a prevention
of bacterial growth through the digestion
process
Endogenous material
Enzyme found in secretions such as tears and
saliva and is capable of destroying bacteria
Lysozymes
Other soluble innate components that protects
us from the pathogenic bacteria:
interleukines,
Prostaglandins, and Leukotrienes
Acute phase reactants such as
C-reactive protein,
haptoglobin, and ceruloplasmin
which either
coat bacteria or remove substances that might
promote bacterial growth
C reactive proteins, haptoglobin and ceruplasmin
are mainly involved in the
inflammation.
Acute phase reaction
is a polypeptide that acts to APRs.
They are mainly involved in the triggering
factors of the other activities of the cell.
Cytokines
process is
enhanced by the activation of the alternative
complement cascade
Phagocytosis
is the cell eating cell
Phagocytosis
It is triggered by the microbial cell walls or
other products of the microbial metabolism
Phagocytosis
are
cellular defense mechanisms that are mainly
involved in the process of Phagocytosis
Neutrophil, macrophages and monocytes
Adaptive immunity Also called
Specific immunity or acquired immunity
The secondary response is better than the primary
response because it has memory B cells.
Adaptive immunity
The mechanism of the adaptive immunity
memory of B cell
Defense mechanism against the extracellular bacteria
occurs
Adaptive immunity
Against exotoxins
and other secreted bacterial products
Antibody production
Activation of Classical pathway
Cell lysis
is the formation of membrane attack complex
and the end result is cell lysis
MAC
other branch of a specific
immune response and helpful in attacking intracellular
bacteria such as Mycobacterium tuberculosis,
Legionella pneumophila , Listeria monocytogenes and
Rickettsia species
Cell mediated immunity
Cell Mediated Immunity other branch of a specific
immune response and helpful in attacking intracellular
bacteria such as
Mycobacterium tuberculosis
Legionella pneumophila
Listeria monocytogenes
Rickettsia species
Production of _________ as by product can aid to enhance phagocytosis
opsonin’s
Three main mechanisms:
OPPOSING IMMUNE RESPONSE
- Avoiding antibody
- Blocking phagocytosis
- Inactivating the complement cascade
Bacteria that can perform this mutation.
Streptococcus agalactiae
Streptococcus pyogenes
is capable of graph rejection
Major histocompatibility complex
Different microorganisms that can cleave the IgA2:
a. Neisseria gonorrhoeae
b. Haemophilus influenza
c. Streptococcus sanguis
inhibition of several stages in phagocytosis
Blocking phagocytosis
is towards the stimulus
positive chemotaxis
is away from the stimulus
Negative chemotaxis
can inhibit the
release mechanism of chemotactic factors
Neisseria gonorrhea
M protein. A
group A streptococcus, inhibition of
adhesion
Streptococcus pyogenes
Encapsulated bacteria
Neisseria meningitides
Streptococcus pneumoniae
Yersinia pestis
Haemophilus influenzae
Klebsiella pneumoniae
inhibition of phagolysosome
formation
Mycobacterium tuberculosis
Mycobacterium leprae
Salmonella spp.
has Leukocidin that will block the
process of phagocytosis
Staphylococcus
Listeria monocytogenes has
Listeriolysin O
Streptococcus has
Streptolysin
do not bind the
complement component C3b
Encapsulated bacteria
important in
enhancing phagocytosis
C3b
takes part in the complex form of alternative
classical and elected pathway
C3b
are gram-positive spherical, ovoid, or
lancet-shaped organisms that are catalase negative and
are often seen in pairs or chains.
Streptococci
Streptococci are divided into groups or
serotypes/serogroup on the basis of certain cell wall
components.
Serotype/Serogroup
Group-Specific Carbohydrate
Serve as the virulence factor for the streptococci
through M and T protein
Serotype/serogroup
Outermost cell wall components contains two
major proteins known as the M and T protein.
Serotype/Serogroup
Interior to the protein layer is the group-specific
carbohydrate that divides streptococci into 20
defined groups, designated A through H and K
through V.
Group-Specific Carbohydrate
Group A
Streptococcus pyogenes
Group B
Streptococcus agalactiae
Group C
Equisimilis
Streptococcus equi
Streptococcus dysagalactiae
Streptococcus zooepidemicus
Group D
Streptococcus bovis
Enterococcus faecalis,
Enterococcus faecium,
Enterococcus durans
is one of the most
common and ubiquitous pathogenic bacteria and
causes a variety of infection.
Streptococcus pyogenes
is the major virulence factor of the
group.
M protein
responsible
for the rash seen in scarlet fever and also appear
to contribute to pathogenicity.
Pyrogenic exotoxins A, B, and C
Production of enzymes also add to its virulence factor.
These includes:
Exoenzymes
The most diagnostically important antibodies are the
following:
Anti-streptolysin O (ASO), anti-DNase B,
anti-NADase, and anti-hyaluroni dase.
Presence of these antibodies is an indication of Group
A streptococcus infection and is seen in many
conditions/ disease like
Scarlet fever
Acute glomerulonephritis
Acute Rheumatic fever
Necrotizing fasciitis
streptococcal toxic shock syndrome
Employs the principle of Passive agglutination.
ASO AGGLUTINATION TEST
is the indirect type of the
agglutination
Passive agglutination
is accompanied by a carrier particle
Antigen
Significant titer: Aso
adult: 240 Todd unit or 240 IU/mL
Children: 320 Todd units or 320 IU/mL
Anti-streptolysin O agglutination test Replaced by
Nephelometry
Antigen Reagent:
Streptolysin
Reacts with patients Anti-Streptolysin
Precipitation
indicative of Streptococcal
glomerulonephritis
Anti-DNAse