Cross reactivity refers to the ability of an individual antibody combining site to react with more than one antigenic determinant.
Cross reactions may arise because the cross reacting antigen shares an epitope in common with the immunizing antigen.
Cross reactions may arise when an epitope is structurally very different to one on the immunizing antigen (multispecificity).
A and b
All of the above
T/F
The higher the affinity of the antibody for the antigen, the more unstable will be the interaction. F
The ratio between the antigen and antibody influences the detection of antigen-antibody complexes. T
If the antigen is particulate, the reaction of an antibody with the antigen cannot detected by agglutination of the antigen. F
Match
titre
prozone
The lack of agglutination at high concentrations of antibodies. B
The maximum dilution that gives visible agglutination. A
Match
Direct Coomb's Test
Agglutination
Radial Immunodiffusion
Immunoelectrophoresis
A complex mixture of antigens is placed in a well punched out of an agar gel and the antigens are electrophoresed so that the antigen are separated according to their charge. D
Mancini C
Detection of anti-rhesus factor (Rh) antibodies. B
Determination of blood types or antibodies to blood group antigens. A
Match
immunofluorescence
ELISA
Compliment Fixation
Measurement of an enzymatic reaction associated with immune complexes. B
Flow Cytometry A
Cells are lysed C
Multiple Choice
With regard to agglutination
All antibodies can theoretically agglutinate particulate antigens
Antibody is mixed with the particulate antigen and a positive test is indicated by the agglutination of the particulate antigen.
Antibody synthesis is balanced by antibody decay so that there in no net increase in antibody concentration. C
The rate of antibody degradation exceeds that of antibody synthesis and the level of antibody falls. D
The antigen is recognized as foreign and the cells begin to proliferate and differentiate in response to the antigen. A
The antibody concentration increases exponentially as the B cells that were stimulated by the antigen differentiate into plasma cells which secrete antibody. B
T/F
The log phase in a secondary response is more rapid and higher antibody levels are achieved compared to the primary response. T
The decline phase in a secondary response is not as rapid as in the primary response and antibody may persist for months, years or even a lifetime. T
In general secondary responses are only elicited by the same antigen used in the primary response. T
Match
Primary response
Secondary response
The major class of antibody produced is IgM. A
Affinity maturation is less pronounced after challenge with antigen. A
Fc region of the antibody interacts with Fc receptors on phagocytic cells rendering the pathogen more readily phagocytosed. B
Protein cascade by antibody can result in lysis of certain bacteria and viruses. C
Binding of antibody to the pathogen or foreign substance antibodies can block the association of the pathogen with their targets. A
Multiple Choice
Cytotoxic T lymphocytes
are a subset of T lymphocytes that express a unique antigen on their surface called CD4.
recognize antigens from the pathogen that are displayed in the cytoplasm of the infected cell.
kill by inducing apoptosis in the infected cell.
All of the above
None of the above
Th1 Helper T cells
are a subset of T cells that express a unique antigen on their surface called CD8.
are the primary defense against intracellular pathogens that live within vesicles.
can’t recognize antigen from the pathogen that are expressed on the surface of infected cells.
None of the above
T/F
All cells of the immune system originate from a hematopoietic stem cell in the bone marrow. T
Cells of the innate immune system include phagocytic cells (monocyte/macrophages and PMNs), NK cells, basophils, mast cells, eosinophiles and platelets. T
Antigen presenting cells (APCs) are a heterogenous population of red blood cells that play an important role in innate immunity. F
A characteristic feature of APCs is the expression of a cell surface molecule encoded by genes in the major histocompatibility complex, referred to as class I MHC molecules. F
Cells that make up the adaptive (specific) immune system include the B and T lymphocytes. T
Match
CD4
CD8
CD19
Cytotoxic T cells B
Helper T cells A
B cells C
Multiple Choice
The Clonal Selection Hypothesis states that
Each lymphocyte bears a single type of receptor with a unique specificity.
Lymphocytes bearing receptors for self molecules are deleted at an early stage in lymphoid cell development and are therefore absent from the repertoire of mature lymphocytes.
The differentiated effector cells derived from an activated lymphocyte will bear receptors of an identical specificity to those of the parental cell from which that lymphocyte was derived.
Th2 cells recognized the carrier determinants and B cells recognized haptenic determinants.
T cells can function both in antigen recognition and in antigen presentation.
A and b
None of the above
B cells are not the best antigen presenting cell in a primary antibody response. T
B cells express immunoglobulin and class II MHC molecules on their cell surface. T
Memory T cells have a high affinity immunoglobulin receptor (due to affinity maturation), which allows them to bind and present antigen at much lower concentrations than that required for macrophages or dendritic cells. F
Cytokines produced by activated Th2 cells not only stimulate proliferation and differentiation of B cells. T