3. Immunology in Blood Banking Flashcards
Examples of foreign substances
- Viruses
- Bacteria
- Fungi
- Parasites
Humoral Immunity
- Mediated by fluids in IS (e.g. plasma, saliva, other secretions)
- Antibodies - immunoglobins (immune-globulin-y)
- Antibodies - bind to antigens (1:1 specificity)
- Ab-Ag: eventual destruction of Ag
Cellular Immunity
Mediated by various cells in IS
•Macrophages (engulf/phagocytize)
•T Cells – w/help from MHC molecules – recognize foreign antigens
•T Cells – elim. fungal/viral infections, intracellular parasites, tissue grafts, tumors
•Major Histocompatibility Complex molecules – determine human leukocyte antigens (HLA) present on leukocytes and other cells … GVHD
Innate Immunity: Primary Defense Mechanisms
(1) Physical: Skin, mucous membranes, cilia, cough reflex
(2) Biochemical: Secretions (sweat, tears, saliva, mucus)
(3) Low pH (vagina/stomach)
Innate Immunity: Secondary Defense Mechanisms
(1) Cellular: phagocytic cells, e.g. macrophage-dendritic cells, monocytes, PMNs, NK cells
(2) Humoral/Biochemical: complement alternate pathway, cytokines, acute inflammatory reaction
Third Line of Defense: Cellular vs. Humoral
Cellular
- Lymphocytes (T cells, TH, TC, T memory cells)
- B Cells (B memory cells, Plasma cells) Cytokines
Humoral
- Antibodies
- Complement-classic pathway
- Cytokines
Immunological Response
- T cells, B cells
- T helper cells
- Suppressor T cells
- Cytotoxic T cells
- Natural Killer cells
Humoral Response to Foreign Antigen: Intro
- Phagocytosis of Ag by macrophage
- Presented on surface of APC within MHC II molecule
- Activates B-cell (ab production: clonal selection & memory cells)
Humoral Response to Foreign Antigen: Initial Response
- Long “lag” phase
- Significant period of IgM antibody production prior to IgG antibody production
Humoral Response to Foreign Antigen: Anamnestic Response
- Short “lag” time
- Rapid antibody production
- Almost entirely IgG response
IgG: Functions
Can cross the placenta
IgM: Functions
- Can react at Immediate Spin phase
- Can mask clinically significant antibodies
Ab Structure: Fab vs. Fc regions
Fab: binds to ag
Fc: complement fixation
1st Stage: Sensitization
Physical attachment of Ab in plasma to Ag on RBC Reactivity (in vitro) is affected by: - [Ag] and [Ab] - pH - Temperature - Ionic strength - Incubation time
2nd Stage: Lattice Formation
(1) Physical attachment of multiple
(2) Ag-Ab complexes e.g. Size relationship
Lattice formation is affected by:
- Characteristics of Ab molecule
- Number of Ag sites
- Location of Ag sites
- Zeta potential
