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C Reactive Protein by Mustafa
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1
C REACTIVE PROTEIN
BY: M S RAHMAN MODERATOR: DR. VARSHA A SINGH
2IntroductionCRP
An acute phase protein
In response to different inflammatory stimuli
Infection or tissue damage
Produced, mainly in the liver
Extra hepatic - neurons, atherosclerotic plaques, monocytes, and lymphocytes.(The mechanisms regulating synthesis - unknown)
Phylogenetically high- plasma protein
3Acute-phase protein
Plasma concentration- increases (positive ) - decreases (negative)
- least 25 percent - inflammatory disorders.
Positive APP: - CRP,mannose binding protein,
Complement factors,ferritin, Ceruloplasmin, serum
amyloid A etc.
Negative APP:- Albumin, transferrin, retinol-binding protein, antithrombin,
transcortin
4History First acute-phase protein
It was discovered by Tillett and Francis in 1930 in the plasma of patients during the acute phase of pneumococcal infection.
CRP, named for its capacity to precipitate the somatic C-polysaccharide of Streptococcus pneumoniae.
5STRUCTURE OF CRP
An annular (ring-shaped), pentameric protein .
composed of five identical nonglycosylated polypeptide subunits.
Half-life - 19 hours , constant , health and disease.
Molecular weight -25106 Da
6STRUCTURE OF CRP
Belongs to the pentraxin family of calcium dependent ligand-binding plasma proteins
7Production
This is the early and rapid host response to tissue injury.
Local expansion of pathogen number
Direct activation of compliment in tissues
Degranulation of mast cells
8 Release of inflammatory mediators
Systemically active mediators:
(IL-1, IL-6, TNF-α)
Initiate production of CRP in liver
Activation of C/EBP gene at transcription level
Release of CRP in circulation
9Binding of CRP with phosphocholine Receptors
Bacterial cellwall
Apoptotic Cell
Inflammated tissue
10
Phagocytosis of bacteria with the production of CRP
11
CRP PRODUCTION AND KILLING OF APOPTOTIC CELLS
12
CRP PRODUCTION AND KILLING OF
INFLAMMATED TISSUE
13
Hepatic synthesis –
Very rapid, single stimulus. Healthy young adult-
Median concentration 3.0 mg/l.
Serum concentrations rise - 6 hr (above 5 mg/l )
-peaks around 48 hours.
CLINICAL APPLICATION
14
RANGE OF CRP LEVELS
VIRAL INFECTIONS: <40mg/l
BACTERIAL INFECTIONS: 40-200 mg/l
SEVERE BACTERIAL INFECTIONS/ TRAUMA/ BURNS: >200 mg/l
Following an acute-phase stimulus-
-Increase up to 10000-fold
15
Acute Inflammation
ChronicInflammation
Tissue Injury
16
A. Acute inflammation:
Bacterial infection
Pneumococcal pneumonia
Acute rheumatic fever
Bacterial endocarditis
Staphylococcal osteomyelitis
17
B. Chronic inflammation:
Systemic lupus erythematosis Rheumatic arthritis Reiter’s syndrome, psoriatic
arthriopathy, arthritis following jejuno-ileal bypass
Polyarteritis nodosa, disseminated systemic vasculitis, coetaneous
vasculitis Polymyalgia rheumatica
18
Crohn’s disease Ulcerative colitis Dermomyositis Osteoarthritis Neoplastic diseases Smokers Obesity Diabetes
19
C. Tissue injury:
Tissue injury and surgery
Acute myocardial ischemia
20
CLINICAL USES OF CRP
1. Screening
Infection
Inflammation/ Tissue damage
Obesity/Hypertension- risk of CHD
DM type II
Atherosclerosis.
2.Diagnosis of Meningitis-
Bacterial/ viral
Monitoring of the response to treatment of inflammation and infection.
e.g. : acute pancreatitis
Diagnostic Prognostic
21
Lab Diagnosis
Quantitative
Semiquantitative rapid latex Agglutination
ELISAChemiluminescent
ImmunoassayLaser nephlometryBNA nephelometer Quantum dots and immunochromatogr
aphic testImmunoturbidimetr
y
Qualitative
Latex Agglutination
22
Latex agglutination test
Principle
CRP antigen + mono specific anti-human CRP
Agglutination
Detect greater then 6µ/ml CRP.
23
Semiquantitave Rapid latex slide test
24
Quantitative Method
ELISASandwich Assay
(Peroxidase)
25
Quantum dots and immunochromatographic test
Rabbit IgG
Human CRP
QD/anti-CRP conjugate
QD-labeled goat-anti-rabbit Ab
Quantum dots (QDs) are introduced as fluorescent probes and immunochromatographic strips to develop quantitative fluorescence point-of-care tests (QF-POCT) to analyze C-reactive protein (CRP) levels
sample pad Test line Control line Absorbent pad
Y CRP Ab2
26
Quantum dots and immunochromatographic test
Distance from sample pad
Flu
ore
scen
ce in
ten
sit
y
27Quantitative Method
Use Streptavidin-HRP as enzyme and enhanced ECL system as substrate reagent.
Relative luminosity values (RLU) is scanned by photon counter reader
Chemiluminescent Immunoassay Kits
28
Quantitative Method Laser Nephlometry
29
Principle
30
Light Source: polychromatic tungsten filament lamp
Monochromator : captures light of multiple
wavelength and changes to singlewavelength.
(
31
Sample: Ag-Ab Complex
scattered light produced
Photodetector
an electronic signal
converted to a turbidity value.
interaction of the incident light and the sample volume
32
Ab complex
Immunoturbidimetry-
33
Light Source: polychromatic tungsten filament lamp
Monochromator : captures light of multiple
wavelength and changes to singlewavelength.
(
34
Sample: Ag-Ab Complex
Absorbed light produced
Photodetector
an electronic signal
converted to a turbidity value.
interaction of the incident light and the sample volume
35
THANK YOU