Unit #5C – Clinical
Laboratory Testing –
Basic
Serology/Immunology
Cecile Sanders, M.Ed.,
MLS(ASCP)
Unit #5C – Clinical Laboratory
Testing - Basic
Serology/Immunology
 The
Immune System
– Complex system of tissues, cells, cell
products, & biologically active
chemicals
– Produces an Immune Response
– Defense mechanism against foreign
substances called “antigens” (ag)
Unit #5C – Clinical Laboratory
Testing - Basic
Serology/Immunology
 Natural
Resistance vs. Specific
Immunity
– Natural Resistance
 Includes
physical barriers (skin, mucous
membranes, etc.), white blood cells like
neutrophils, and proteins that cause
inflammation
 Non-specific
 Does not require exposure to an antigen
Unit #5C – Clinical Laboratory
Testing - Basic
Serology/Immunology
– Specific Immune Response
 Recognition
– recognizes foreign antigens and
distinguishes them from “self”
 Specificity – reacts with a specific antigen
without reacting with others
 Memory – “anamnestic response”
Unit #5C – Clinical Laboratory
Testing - Basic
Serology/Immunology
 Cells,
Tissues, and Organs of Immune
System
– Lymphocytes – B Cells and T Cells
– Primary Lymphoid Organs = Bone Marrow
and Thymus (glandular
tissue located
at the base of the
sternum)
Unit #5C – Clinical Laboratory
Testing - Basic
Serology/Immunology
– Secondary Lymphoid Tissue = Spleen, Lymph
Nodes, Appendix, and Tonsils

Humoral Immunity
– B Lymphocytes produce antibodies against specific
antigens
– Good protection against bacteria, toxins, and
circulating antigens

Cell-Mediated Immunity
– T Lymphocytes protect against viruses, fungi,
tumor cells, and intracellular organisms
Unit #5C – Clinical Laboratory
Testing - Basic
Serology/Immunology
 Immunoglobulins
(Ig)
– Also called “antibodies” (ab)
– Named by placing the prefix anti before
the name of the antigen with which the
antibody reacts

Unit #5C – Clinical Laboratory
Testing - Basic
Serology/Immunology
Primary vs. Secondary Antibody Response
– Primary occurs after first exposure to an antigen
– Secondary Response



Sometimes called “anamnestic response”
Lymphocytes remember the antigen
Immunizations or vaccinations (such as for measles, tetanus,
etc.) are effective because of the Secondary Response
– Seroconversion = when an antibody is detectable in
patient who has previously tested negative for the
antibody
Unit #5C – Clinical Laboratory
Testing - Basic
Serology/Immunology
First and Second Responses to Antigens
Unit #5C – Clinical Laboratory
Testing - Basic
Serology/Immunology
 Categories
of Conditions Associated
with Immune System Abnormalities
– Autoimmune Disease (RA, Lupus, Juvenile
Type I Diabetes, Myasthenia Gravis)
– Hypersensitivies (Hay fever, Asthma,
Dermatitis)
– Malignancies (Lymphomas, Leukemias,
Multiple Myeloma)
Unit #5C – Clinical Laboratory
Testing - Basic
Serology/Immunology
 Categories
of Conditions Associated
with Immune System Abnormalities
(cont’d)
– Acquired Immunodeficiencies (Infections,
Systemic Disease, Malignancies, Reactions
to Drugs, Irradiation)
– Congenital Immunodeficiencies (DiGeorge
Syndrome, Aggamaglobulinemia, SCID –
Severe Combined Immune Deficiency)
Unit #5C – Clinical Laboratory
Testing - Basic
Serology/Immunology
 Tests
of Immune Function
– Based on Antigen-Antibody Reactions
 May
be qualitative (positive or negative)
 May be quantitative (Titer = Reciprocal of the
highest dilution of patient’s serum showing a
positive reaction with antigen)
– Principles of Immunological Tests
 Agglutination
and Agglutination Inhibition –
visible clumping of cells or particles due to their
reaction with an antibody
Unit #5C – Clinical Laboratory
Testing - Basic
Serology/Immunology
Agglutination of Red Blood Cells with
Antibody
Unit #5C – Clinical Laboratory
Testing - Basic
Serology/Immunology
– Principles of
Immunological Tests
(cont’d)
 Precipitation
–
formation of an
insoluble complex
when a specific
antibody is reacted
with a soluble antigen
(usually in a gelatinlike substance)
Unit #5C – Clinical Laboratory
Testing - Basic
Serology/Immunology
– Principles of Immunological Tests (cont’d)
 Labeled
Antibody Techniques – Molecules
(labels) are attached to the antibodies,
producing a visible reaction. Labels may be
dyes, enzymes or radioisotopes.
Unit #5C – Clinical Laboratory
Testing - Basic
Serology/Immunology
Enzyme Linked Immunoassay (ELISA)
Unit #5C – Clinical Laboratory
Testing - Basic
Serology/Immunology
Visit this website for a virtual immunology
lab visit and experiment:
http://www.hhmi.org/biointeractive/vlabs
/immunology/index.html
Try to complete the lab by following
website directions! Very cool!
Unit #5C – Clinical Laboratory
Testing - Basic
Serology/Immunology
 Resources
– Basic Clinical Laboratory Techniques,
Estridge and Reynolds, Thomson/Delmar
Learning, Fifth Edition, 2008