CHT Exam Questions and Answers
It is possible to convert the plasma
into serum by recalcifying the plasma and allowing coagulation to occur .Correct Answer Calcium is
added to the plasma to form a complex with the citrate present in the anti-coagulant. 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. Correct Answer absorbed
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. Correct Answer autoantibody
_________ are typically
cold reacting (4oC) and________are typically warm reacting (22-37oC).Correct Answer
Autoantibodies
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 ___________.Correct Answer false positive
reactivity.
DTT Correct Answer dithiothreitol, also known as Cleland's Reagent
DTT inactivates IgM molecules by cleaving the _________ in the
pentamer structure. Correct Answer disulphide bonds
Heat inactivation works by cleaving the disulphide bonds in the
pentamer structure, but is less specific than _____.Correct Answer DTT.
, CHT Exam Questions and Answers
ALA Correct Answer therapeutic antilymphocyte
antibodies
Thymoglobulin Correct Answer purified, pasteurized, gamma immune globulin,
obtained by immunization of rabbits with human thymocytes
OKT3Correct Answer a 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. Correct Answer false positive
ALA removal is accomplished by absorption using _____coated with anti-rabbit or anti-mouse
immunoglobulin for Thymoblobulin or OKT3, respectively. Correct Answer magnetic beads
serum preparations Correct Answer 1. 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? Correct Answer Calcium 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? Correct Answer
Typically, 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
, CHT Exam Questions and Answers
removing IgM antibodies. However, DTT can also affect the _______ in IgG antibodies .Correct
Answer disulfide bonds
What happens if we don't remove OKT3 prior to cytotoxicity assays? Correct Answer OKT3 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_______. Correct Answer ~1.077 g/ml.
Cells with a higher density than FH Correct Answer red cells and granulocytes
cells of a lower density than lymphocytes Correct Answer platelets
isolation of cells from lymph nodes or spleen is normally fast and simple and leads to greater _____
and ______Correct Answer cell 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 _______.Correct Answer macrophages
erythrocytes
platelets.
intrinsic cell properties Correct Answer cell size and
granularity of the cell.
One method of lymphocyte isolation (HP) utilizes an intrinsic cell property, __________, by using a
extrinsic cell properties. Correct Answer cell surface marker, phagocytic capabilities and
adherence capabilities.
, CHT Exam Questions and Answers
Immunomagnetic bead separations use the extrinisic property of __________ as the
isolation target. Correct Answer cell surface markers
Nylon wool isolation incorporates the extrinsic property of ___________Correct Answer adherence
for B cells.
Nylon wool isolation procedure: Correct Answer Lymphocytes 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. Correct Answer nonspecific binding
Various cell purification methods are Correct Answer Percoll and Thrombin: remove granulocytes,
platelets, and dead cells
Lympho-kwik: isolate specific populations (T &/or B lymphocytes, lymphocytes and monocytes)
centrifugation slow/short: remove platelets in the supernatant
carbonyl iron: Granulocytes ingest altering density (heavier)
Dnase: remove dead cells
Lymphocyte interface is
indistinctive or thin Correct Answer Hyperlipemic blood sample
Centrifugation force is too low and time too short
Adjust centrifugation to 2000 x g for 25 min
Presence of RBC in the
It is possible to convert the plasma
into serum by recalcifying the plasma and allowing coagulation to occur .Correct Answer Calcium is
added to the plasma to form a complex with the citrate present in the anti-coagulant. 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. Correct Answer absorbed
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. Correct Answer autoantibody
_________ are typically
cold reacting (4oC) and________are typically warm reacting (22-37oC).Correct Answer
Autoantibodies
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 ___________.Correct Answer false positive
reactivity.
DTT Correct Answer dithiothreitol, also known as Cleland's Reagent
DTT inactivates IgM molecules by cleaving the _________ in the
pentamer structure. Correct Answer disulphide bonds
Heat inactivation works by cleaving the disulphide bonds in the
pentamer structure, but is less specific than _____.Correct Answer DTT.
, CHT Exam Questions and Answers
ALA Correct Answer therapeutic antilymphocyte
antibodies
Thymoglobulin Correct Answer purified, pasteurized, gamma immune globulin,
obtained by immunization of rabbits with human thymocytes
OKT3Correct Answer a 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. Correct Answer false positive
ALA removal is accomplished by absorption using _____coated with anti-rabbit or anti-mouse
immunoglobulin for Thymoblobulin or OKT3, respectively. Correct Answer magnetic beads
serum preparations Correct Answer 1. 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? Correct Answer Calcium 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? Correct Answer
Typically, 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
, CHT Exam Questions and Answers
removing IgM antibodies. However, DTT can also affect the _______ in IgG antibodies .Correct
Answer disulfide bonds
What happens if we don't remove OKT3 prior to cytotoxicity assays? Correct Answer OKT3 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_______. Correct Answer ~1.077 g/ml.
Cells with a higher density than FH Correct Answer red cells and granulocytes
cells of a lower density than lymphocytes Correct Answer platelets
isolation of cells from lymph nodes or spleen is normally fast and simple and leads to greater _____
and ______Correct Answer cell 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 _______.Correct Answer macrophages
erythrocytes
platelets.
intrinsic cell properties Correct Answer cell size and
granularity of the cell.
One method of lymphocyte isolation (HP) utilizes an intrinsic cell property, __________, by using a
extrinsic cell properties. Correct Answer cell surface marker, phagocytic capabilities and
adherence capabilities.
, CHT Exam Questions and Answers
Immunomagnetic bead separations use the extrinisic property of __________ as the
isolation target. Correct Answer cell surface markers
Nylon wool isolation incorporates the extrinsic property of ___________Correct Answer adherence
for B cells.
Nylon wool isolation procedure: Correct Answer Lymphocytes 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. Correct Answer nonspecific binding
Various cell purification methods are Correct Answer Percoll and Thrombin: remove granulocytes,
platelets, and dead cells
Lympho-kwik: isolate specific populations (T &/or B lymphocytes, lymphocytes and monocytes)
centrifugation slow/short: remove platelets in the supernatant
carbonyl iron: Granulocytes ingest altering density (heavier)
Dnase: remove dead cells
Lymphocyte interface is
indistinctive or thin Correct Answer Hyperlipemic blood sample
Centrifugation force is too low and time too short
Adjust centrifugation to 2000 x g for 25 min
Presence of RBC in the
