Unit 1 Introductory Concepts Flashcards
What is the study of blood group antigens and antibodies called?
Immunohematology
Who discovered the ABO blood groups in 1901?
Karl Landsteiner
What improved preservative solution was introduced by Gibson?
Citrate-phosphate-dextrose (CPD)
What are RBC antibodies in individuals without previous exposure to RBC antigens through transfusion, injection, or pregnancy called?
Naturally occurring antibodies
What causes agglutination by adjusting zeta potential between RBCs?
Enhancement media
What is an antigen?
A foreign molecule that binds specifically to an antibody or a T-cell receptor
What is the immunodominant sugar of A antigen?
N-Acetyl-D-galactosamine
What is the second most immunogenic blood group antigen?
Rh D (+)
What is a hapten?
An incomplete antigen that reacts to antibodies but cannot induce antibody formation
What is the ideal pH for antigen-antibody reactions?
7.0 (physiologic is ideal)
What type of antibody is IgM?
Cold-reacting antibody
What is the predominant antibody produced in the secondary immune response?
IgG
Which IgG subclass best passes the placenta?
IgG1
What antibody is most commonly encountered in the ABO system?
IgM
What is the most common enhancement media used in laboratories?
Low Ionic Strength Solution (LISS)
What enzyme is isolated from fig plants and used in blood banking?
Ficin
What does anti-human globulin (AHG) reagent do?
Acts as a bridge between antibodies and determines if RBCs are coated with antibodies or complement
What is the function of citrate in anticoagulants?
Chelates calcium and prevents coagulation
What is the significance of the ABO blood group system?
It was the first blood group system discovered, essential for transfusions.
What antibody is involved in mucosal immunity?
IgA
What are naturally occurring antibodies also known as?
Non-RBC Stimulated Antibodies
What does the term ‘alloantibodies’ refer to?
Antibodies targeting antigens absent in a patient’s RBCs
What does the term ‘autoantibodies’ refer to?
Antibodies targeting antigens present in a patient’s RBCs
What is the main purpose of the mononuclear phagocyte system?
Clears antigen-antibody complexes from the body
What is the first successful animal-to-animal blood transfusion credited to?
Richard Lower
What is the lock and key mechanism in antigen-antibody reactions?
The reciprocal relationship (fit) between the antigen and its binding site on the antibody
What is the temperature range for IgM agglutination reactions?
22-24°C or 4-6°C
What is the function of polyethylene glycol (PEG) in blood banking?
Removes excess water to enhance antigen-antibody reactions
What are the properties that influence antigen immunogenicity?
Size, complexity, conformation, charge, accessibility, solubility, digestibility, chemical composition
What are the two stages of hemagglutination?
Sensitization and lattice formation
What factor influences the distance between RBCs during agglutination?
Zeta potential
What causes hemolysis during antibody reactions?
Activation of complement proteins
What is the primary significance of anti-D antibodies in Rh-negative mothers?
Prevent development of anti-D antibodies after delivering Rh-positive infants
What is an epitope?
The exact antigen site recognized by an antibody
What is a paratope?
The exact antibody site that binds to the antigen
What is the role of the J chain in antibodies?
Joins antibody monomers, seen in pentameric IgM
What is the effect of high avidity in antigen-antibody reactions?
Leads to low dissociation and stronger binding
What does the classical complement pathway result in?
Cell lysis via antigen-antibody reaction
What factors influence host immune responses?
Nutritional status, hormones, genetics, age, race, exercise level, disease, injury
What are the subclasses of IgG antibodies?
IgG1, IgG2, IgG3, IgG4
What does polyspecific AHG target?
Both IgG antibodies and complement proteins
What is the main characteristic of monoclonal antibodies?
They are homogeneous and derived from a single ancestral cell
What reaction occurs when antigen excess causes a false-negative result?
Post-zone reaction
What reaction occurs when antibody excess causes a false-negative result?
Pro-zone reaction
What is the incubation time for LISS in blood banking?
10-15 minutes
What does the term ‘chimera’ refer to in immunology?
Presence of different populations of cells in a single individual
What is the result of transfusing IgA into an IgA-deficient patient?
Severe anaphylaxis
Who first introduced sodium citrate as an anticoagulant?
Hustin
Who developed the acid-citrate-dextrose (ACD) formula?
Loutit and Mollison of England
