CHT EXAM COMPLETE STUDY
GUIDE WITH CORRECT ANSWERS
2026
It is possible to convert the plasma
into serum by recalcifying the plasma and allowing coagulation to occur. gCalcium is added to the
plasma to form a complex with the citrate present in the anticoagulant. This restores a normal ionized
calcium level allowing clotting to occur.
Polyspecific antiserum can be______ with lymphocytes to determine if there is a single
antibody or multiple antibodies. gabsorbed
Another application of lymphocyte absorption is to use the patient's own cells to remove_____.
Absorption can be performed
at cold or warm temperatures depending on the type of antibody. gautoantibody
_________ are typically
cold reacting (4oC) and________are typically warm reacting (22-37oC). gAutoantibodies
,B cell antibodies
Patient serum may contain autoantibodies and/or IgM antibodies that may interfere the binding of anti-
HLA IgG antibodies to the antigen. In complement dependent assays (CDC), IgM antibodies
can activate complement; potentially leading to ___________. gfalse positive reactivity.
DTT gdithiothreitol, also known as Cleland's Reagent
DTT inactivates IgM molecules by cleaving the _________ in the pentamer
structure. gdisulphide bonds
Heat inactivation works by cleaving the disulphide bonds in the pentamer
structure, but is less specific than _____. gDTT.
ALA gtherapeutic antilymphocyte antibodies
Thymoglobulin gpurified, pasteurized, gamma immune globulin, obtained by immunization of
rabbits with human thymocytes
OKT3 ga murine IgG monoclonal antibody directed against CD3
If these therapeutic antilymphocyte antibodies are present in the patient serum, they
can cause_______ reactivity in T cell cytotoxic assays. gfalse positive
ALA removal is accomplished by absorption using _____coated with anti-rabbit or anti-mouse
immunoglobulin for Thymoblobulin or OKT3, respectively. gmagnetic beads
serum preparations g1. Recalcificiation of plasma
,2. Adsorption with lymphocytes 3.
Inactivation of IgM antibodies
a. DTT treatment
b. Heat Inactivation
4. Depletion of therapeutic anti-lymphocyte antibodies from serum
Why is calcium added to plasma to convert it to serum? gCalcium is added to the plasma to combine
with the citrate present in the anticoagulant.
This restores a normal ionized calcium level and allows clotting to occur.
At what temperature should serum absorption with lymphocytes be performed? gTypically, auto-
antibodies are cold reacting and should be absorbed at 4oC while alloantibodies are warm
reacting and should be absorbed at 37oC.
DTT treatment is more specific than heat treatment in
removing IgM antibodies. However, DTT can also affect the _______ in IgG antibodies. gdisulfide bonds
What happens if we don't remove OKT3 prior to cytotoxicity assays? gOKT3 is a monoclonal antibody
directed against the CD3 molecule. Therefore, the binding of OKT3 to any CD3+ cell will activate
complement and lyse the target cell. This results in falsely positive reactivity.
Lymphocytes have a density of_______ g~1.077 g/ml.
Cells with a higher density than FH gred cells and granulocytes
cells of a lower density than lymphocytes gplatelets
isolation of cells from lymph nodes or spleen is normally fast and simple and leads to greater
_____ and ______ gcell yield
, viability.
Obtaining lymphocytes from spleen will require an additional FH step along with purification steps due
to a large number of contaminating cells, such as _______ ,______ and _______. gmacrophages
erythrocytes
platelets.
intrinsic cell properties gcell size and granularity of the cell.
One method of lymphocyte isolation (HP) utilizes an intrinsic cell property, __________, by using a
density gradient medium. gcell density
extrinsic cell properties gcell surface marker, phagocytic capabilities and adherence capabilities.
Immunomagnetic bead separations use the extrinisic property of __________ as the
isolation target. gcell surface markers
Nylon wool isolation incorporates the extrinsic property of ___________ gadherence for B cells.
Nylon wool isolation procedure: gLymphocytes are obtained and added to a column packed with nylon
wool. B cells will adhere to the nylon wool at an optimal temperature of 37o C. The non-adherent T cells
can be collected by washing the column several times with warm media. The B cells can then be eluted
by plunging cold media through the column.
Dead cells in a flow cytometry assay can lead to
____________ of monoclonal antibodies and/or fluorochromes. gnonspecific binding
Various cell purification methods are gPercoll and Thrombin: remove granulocytes, platelets, and dead
cells
GUIDE WITH CORRECT ANSWERS
2026
It is possible to convert the plasma
into serum by recalcifying the plasma and allowing coagulation to occur. gCalcium is added to the
plasma to form a complex with the citrate present in the anticoagulant. This restores a normal ionized
calcium level allowing clotting to occur.
Polyspecific antiserum can be______ with lymphocytes to determine if there is a single
antibody or multiple antibodies. gabsorbed
Another application of lymphocyte absorption is to use the patient's own cells to remove_____.
Absorption can be performed
at cold or warm temperatures depending on the type of antibody. gautoantibody
_________ are typically
cold reacting (4oC) and________are typically warm reacting (22-37oC). gAutoantibodies
,B cell antibodies
Patient serum may contain autoantibodies and/or IgM antibodies that may interfere the binding of anti-
HLA IgG antibodies to the antigen. In complement dependent assays (CDC), IgM antibodies
can activate complement; potentially leading to ___________. gfalse positive reactivity.
DTT gdithiothreitol, also known as Cleland's Reagent
DTT inactivates IgM molecules by cleaving the _________ in the pentamer
structure. gdisulphide bonds
Heat inactivation works by cleaving the disulphide bonds in the pentamer
structure, but is less specific than _____. gDTT.
ALA gtherapeutic antilymphocyte antibodies
Thymoglobulin gpurified, pasteurized, gamma immune globulin, obtained by immunization of
rabbits with human thymocytes
OKT3 ga murine IgG monoclonal antibody directed against CD3
If these therapeutic antilymphocyte antibodies are present in the patient serum, they
can cause_______ reactivity in T cell cytotoxic assays. gfalse positive
ALA removal is accomplished by absorption using _____coated with anti-rabbit or anti-mouse
immunoglobulin for Thymoblobulin or OKT3, respectively. gmagnetic beads
serum preparations g1. Recalcificiation of plasma
,2. Adsorption with lymphocytes 3.
Inactivation of IgM antibodies
a. DTT treatment
b. Heat Inactivation
4. Depletion of therapeutic anti-lymphocyte antibodies from serum
Why is calcium added to plasma to convert it to serum? gCalcium is added to the plasma to combine
with the citrate present in the anticoagulant.
This restores a normal ionized calcium level and allows clotting to occur.
At what temperature should serum absorption with lymphocytes be performed? gTypically, auto-
antibodies are cold reacting and should be absorbed at 4oC while alloantibodies are warm
reacting and should be absorbed at 37oC.
DTT treatment is more specific than heat treatment in
removing IgM antibodies. However, DTT can also affect the _______ in IgG antibodies. gdisulfide bonds
What happens if we don't remove OKT3 prior to cytotoxicity assays? gOKT3 is a monoclonal antibody
directed against the CD3 molecule. Therefore, the binding of OKT3 to any CD3+ cell will activate
complement and lyse the target cell. This results in falsely positive reactivity.
Lymphocytes have a density of_______ g~1.077 g/ml.
Cells with a higher density than FH gred cells and granulocytes
cells of a lower density than lymphocytes gplatelets
isolation of cells from lymph nodes or spleen is normally fast and simple and leads to greater
_____ and ______ gcell yield
, viability.
Obtaining lymphocytes from spleen will require an additional FH step along with purification steps due
to a large number of contaminating cells, such as _______ ,______ and _______. gmacrophages
erythrocytes
platelets.
intrinsic cell properties gcell size and granularity of the cell.
One method of lymphocyte isolation (HP) utilizes an intrinsic cell property, __________, by using a
density gradient medium. gcell density
extrinsic cell properties gcell surface marker, phagocytic capabilities and adherence capabilities.
Immunomagnetic bead separations use the extrinisic property of __________ as the
isolation target. gcell surface markers
Nylon wool isolation incorporates the extrinsic property of ___________ gadherence for B cells.
Nylon wool isolation procedure: gLymphocytes are obtained and added to a column packed with nylon
wool. B cells will adhere to the nylon wool at an optimal temperature of 37o C. The non-adherent T cells
can be collected by washing the column several times with warm media. The B cells can then be eluted
by plunging cold media through the column.
Dead cells in a flow cytometry assay can lead to
____________ of monoclonal antibodies and/or fluorochromes. gnonspecific binding
Various cell purification methods are gPercoll and Thrombin: remove granulocytes, platelets, and dead
cells
