Serology 101
Transcript of Serology 101
-
7/28/2019 Serology 101
1/51
SEROLOGY 101
Or How To Interpret Those Funny-Looking
Graphs
Dr. Victoria Bowes
Animal Health Centre
Abbotsford, BC
Presented June 4, 2003
-
7/28/2019 Serology 101
2/51
-
7/28/2019 Serology 101
3/51
Avian Immune System
NON-SPECIFIC IMMUNITY:
anatomicskin, mucus, cilia
body temperature
genetic factors
sneeze, cough, vomitage, nutrition
-
7/28/2019 Serology 101
4/51
Avian Immune System
SPECIFIC IMMUNITY:
Passive (provided in the yolk to chicks)
Acquired (must be produced by the bird)
(by infection or vaccination)
Cellslymphocytes, macrophages Antibodies -produced by B-lymphocytes
Memory
-
7/28/2019 Serology 101
5/51
-
7/28/2019 Serology 101
6/51
The Immune Response
Must recognizeforeign or potentially
harmful intruders
Produce and co-ordinate specific
(antibodies) and non-specific(lymphocytes)reactions to ATTACH, TRAP and
ELIMINATE
-
7/28/2019 Serology 101
7/51
The Immune Response
antibody: a protein produced in response to
the presence of a specificantigen
antigen: a molecule capable of eliciting animmune response, usually large, complex
and foreign
-
7/28/2019 Serology 101
8/51
-
7/28/2019 Serology 101
9/51
-
7/28/2019 Serology 101
10/51
The Immune Response
Example:
An IB virus that has its surface receptors
coated in antibodies cannot attach itself to
the cells lining the trachea, the first step in
infection.
-
7/28/2019 Serology 101
11/51
The Immune Response
PRIMARY: novel foreign antigen isprocessed, specific antibodies are slowly
produced (short-lived) and memory cellsbecome dormant
SECONDARY: memory cells encountertheir specific antigen and are activated,antibody production is rapid and potent
-
7/28/2019 Serology 101
12/51
-
7/28/2019 Serology 101
13/51
Vaccines
Vaccines = INSURANCE (something you
may never use but you be very glad to have
if ever needed)
Live : gives best immune response but
has side effects (weakened strains of virus)
Killed: less side effects but poorer
immune response (excluding adjuvants)
-
7/28/2019 Serology 101
14/51
Serology
The detection of antibodiesin serum
Test methods: plate agglutination
hemagglutination inhibition
ELISA
Interpreting results: negativevaccination
field challenge
-
7/28/2019 Serology 101
15/51
Blood
55% fluid: mostly water
45% solid: cells (500:1 red : white cells),
enzymes, proteins, nutrients
transports oxygen & nutrients while
removing waste
serum Vs plasma
-
7/28/2019 Serology 101
16/51
-
7/28/2019 Serology 101
17/51
The Animal Health Monitoring Lab
-
7/28/2019 Serology 101
18/51
-
7/28/2019 Serology 101
19/51
ELISA
E nzyme
L inked
I mmuno
S orbantA ssay
-
7/28/2019 Serology 101
20/51
ELISA
easily automated
sensitive & specific
antigen-coated test plates capturespecific
antibodies in diluted blood sample and
reagents turn shades of blue depending and
the amount of antibody present
generates computer graph histogram
-
7/28/2019 Serology 101
21/51
The Elisa Plate Reader
-
7/28/2019 Serology 101
22/51
ELISA plate
-
7/28/2019 Serology 101
23/51
-
7/28/2019 Serology 101
24/51
HI plate
-
7/28/2019 Serology 101
25/51
-
7/28/2019 Serology 101
26/51
Serological Strategies
DIAGNOSTIC: field challenge
paired samples
ASSESS VACCINATION RESPONSE:protective and maternal titres
-
7/28/2019 Serology 101
27/51
Serological Strategies
small sample size is used to infer the condition ofa larger population of birds
statistical techniques dictate sample size ofsignificance
variables: flock size 12-24 /air space?
testing type
pooling samples reduces test sensitivity(dilutional)
-
7/28/2019 Serology 101
28/51
Interpretation
Serology results must be interpreted inassociation with other sources of
information: vaccination historyproduction data
condemnation data
cl inical signsnecropsy f indings
-
7/28/2019 Serology 101
29/51
Limitations
seroconversion takes 4-20 days
tests only circulating antibody
static measure (rising, stable, falling)
cant differentiate field vs. vaccine strains
cross-reactions test error
-
7/28/2019 Serology 101
30/51
Titres or Titers
a unit of measurement of antibody
uses pre-determined reference numbers
historically measured by sample dilution
until a standard reaction was produced
dilution = titre
a titre of 32 the antibody of 64
2X the antibody of 16
-
7/28/2019 Serology 101
31/51
Doubling
DilutionsLog Titres
1 0
2 1
4 2
8 3
16 4
32 5
64 6
128 7
256 8
512 9
1024 10
2048 11
Field Challenge Prime Plus Killed
Interpretation
No immunity Maternal Immunity
Poor Immunity
Live Prime Vaccine
2nd Live Prime VaccineProtection Against Mortality
-
7/28/2019 Serology 101
32/51
-
7/28/2019 Serology 101
33/51
-
7/28/2019 Serology 101
34/51
Interpreting Results
123 A BB 18 X 345 IBD-XR 123flock #
A orB1st or 2nd bleeding BBbroiler breeder (or TU, BR)
18age in weeks
Xsubmitter code (hatchery, vet) 345owner code
IBD-XRtest name
-
7/28/2019 Serology 101
35/51
Interpreting Results
MEAN TITRES:
the averagetitrenumber (zero to >10,000)
each titre group (bottom line of graph)represents a different titre range depending
on the virus
-
7/28/2019 Serology 101
36/51
Titre
Group
Reovirus
MG/MS
IB, IBD
NDV
AE
0 0-537 0-395 0-444
1 538-1075 396-999 445-769
2 1076-1999 1000-1999 770-1215
3 2000-2999 2000-2999 1216-1661
4 3000-3999 3000-3999 1662-2107
5 4000-4999 4000-4999 2108-2553
6 5000-5999 5000-5999 2554-2999
7 6000-7999 6000-7999 3000-3444
-
7/28/2019 Serology 101
37/51
Interpreting Results
UNIFORMITY:
%CV (coefficient of variation)
< 30% excellent
30-50% good
51-80% fair> 81% poor or bimodal
-
7/28/2019 Serology 101
38/51
-
7/28/2019 Serology 101
39/51
Standards
Optimum Titres: minimum titre level toprovide long duration immunity for breeder
hens, also assuming protective. Assessed 4weeks post-killed vaccine.
ND 8/10 > 7 IBV 8/10 > 6IBD 8/10 > 8 Reo 8/10 >5
AE 8/10 >4
-
7/28/2019 Serology 101
40/51
-
7/28/2019 Serology 101
41/51
Interpretation
EXAMPLES
The following are typical histograms
-
7/28/2019 Serology 101
42/51
5 week unvaccinated broilers
negative titres
-
7/28/2019 Serology 101
43/51
5 week broilers
IBD vaccination or challenge?
-
7/28/2019 Serology 101
44/51
5 week vaccinated broilers
IBD challenge, poor vaccine?
-
7/28/2019 Serology 101
45/51
62 week layer bloods waning titres
-
7/28/2019 Serology 101
46/51
pre & post-killed IBD titres
-
7/28/2019 Serology 101
47/51
pre & post-killed reovirus titres
+ challenge?
-
7/28/2019 Serology 101
48/51
NDV titres
poor prime boosted by killed vaccine
-
7/28/2019 Serology 101
49/51
IBV
uneven prime, suboptimal titres
-
7/28/2019 Serology 101
50/51
-
7/28/2019 Serology 101
51/51