Immunological and Molecular Diagnostics

Question 1

function of serology

Answer 1

Evaluation of immune status / function
Exposure of animal to infection
Response to vaccination
Diagnosis of immune-mediated disease

Question 2

function of immunoassay

Answer 2

Using labelled antibodies as detection reagents
Presence of pathogen in a biological sample
Measurement of a biomarker
Immunophenotyping

Question 3

blood sample for serum

Answer 3

clotted sample

Question 4

blood sample for cells

Answer 4

citrate/heparin

Question 5

acute phase proteins

Answer 5

C-reactive protein, Serum amyloid A, fibrinogen,
haptoglobin
provide evidence of infl in horses

Question 6

Serological markers of adaptive immunity

Answer 6

antibodies

cytokines

Question 7

measuring total immunoglobulin can be useful in

Answer 7

Failure of passive transfer in foals
Specific Ig deficiency syndromes
Monoclonal / polyclonal gammopathy

Question 8

antigen-specific immunoglobulin useful for

Answer 8

Exposure to pathogen
Response to vaccination
diagnosis of antibody-mediated hypersensitivity - Allergy, Autoimmunity

Question 9

Diagnosis of FPT in foals

Answer 9

blood test 15 – 18 hours of age

Question 10

ELISA can be used to detect either ___ or ____

Answer 10

antigen or antibodies

Question 11

ELISA test early on in an infection vs later on

Answer 11

early test for antigen as antibodies in lag phase

later on test for antibodies as the body is responding to the disease

Question 12

immunofluorescence assay (IFA)

Answer 12

same principle as ELISA exept detection antibody marked with fluorescent marker not enzyme

Question 13

virus neutralization (VN) assay

Answer 13

cultured cells infected with the virus +/- serum from patient
if antibody absent - cells infected

Question 14

VN assay advantage over ELISA or IFA

Answer 14

indicates presence of biologically active antibody

presence of antibody in ELISA does not necessarily mean that it is protective

Question 15

virus neutralising titre

Answer 15

greatest dilation of serum that prevents cell from becoming infected

Question 16

Evaluation of T cell responses

Answer 16

CD4+ T cell

measure cytokine release following stimulation with specific antigen

Question 17

Bovine TB gamma-IFN test

Answer 17

Heparinised blood sample to AHVLA
Culture cells in vitro with mycobacterial antigens (PPD)
Measure IFN-gamma production by ELISA
More sensitive but less specific than tuberculin “skin test”

Question 18

Intradermal skin tesing

Answer 18

Used a lot for diagnosis of small animal allergic skin disease
Immediate-type (IgE-mediated) hypersensitivity

Question 19

Tuberculin test for TB in cattle

Answer 19

Clip hair
Measure skin thickness
Inject PPD (avian & bovine)
Measure skin thickness 72 hrs later

Question 20

Immunodiagnostics for Autoimmunity

Answer 20

coombs test for IMHA
ANA for SLE
measurement of specific autoantibodies

Question 21

detection of pathogen in a sample

Answer 21

sandwich ELISA
IFA
immunohistochemistry

Question 22

immunophenotyping

Answer 22

antibodies against cell-surface markers can tell which cell types are in a sample
can be done on cells in suspension by flow cytometry

Question 23

Identification of pathogen’s nucleic acid in a biological sample

Answer 23

Usually using PCR or qPCR (quantitative PCR)
Pathogen-specific primers / probes tell if sample is +/-ve
16S rRNA sequencing can also be used

Question 24

Genotyping pathogen

Answer 24

Influenza virus H + N genes

Virulence factors

Question 25

disease susceptibility genes

Answer 25

Monogenic vs complex genetic disorder 
Autosomal vs sex-linked 
Dominant vs recessive 
Complete vs incomplete penetrance
PCR based test

Question 26

use of DNA genotyping

Answer 26

parentage
Diagnosis of disease – SOD1 mutation in degenerative myelopathy of GSD, KIT mutations in mast cell tumours
Establishing potential risk of disease in later life
Screening for carrier animals in a breeding population

Question 27

Mast cells and KIT

Answer 27

Tissue mast cell viability is dependent upon the presence of stem cell factor (SCF)
SCF acts through the KIT (c-kit) receptor, which has tyrosine kinase activity.
KIT gene mutations are found in 30-50% of mast cell tumours
The presence of a KIT mutation seems to be associated with more aggressive disease.

Question 28

acute phase proteins serological markers of innate or adaptive immunity?

Answer 28

innate