73 The Structure of Lymphocytes and Plasma Cells

Question 1

3 major blood lymphocyte functional subsets

Answer 1

T lymphocytes, B lymphocytes, and natural killer (NK) cells

Question 2

Usual diameter of lymphoctes

Answer 2

6–15 μm

Small lymphocytes: 6–9 μm
Large lymphocytes: 9–15 μm

Question 3

Mean absolute number of circulating small lymphocytes in normal adults

Answer 3

2.5 × 109/L

Question 4

Children have higher lymphocyte counts that trend downward until they reach adult levels at about age_______years

Answer 4

8–10 years

Question 5

What is the cell being described:

Slightly larger than most lymphocytes, with an increased area of light blue or clear cytoplasm; contains several coarse pink granules, usually 5–15 per cell, and occasional clear vacuoles

Answer 5

Large granular lymphocytes

In a normal adult, approximately 5% but up to 10% to 15% of blood lymphocytes are LGLs

The LGLs in blood are composed of NK cells and a subset of CD8+ T lymphocytes, indistinguishable by their morphology.

Question 6

Infection with___________ causes an increase in blood lymphocytes with a particular activated morphology characterized by small size, scant cytoplasm, and cleaved nuclei with mature chromatin

Answer 6

B pertussis

Question 7

TRUE OR FALSE

Cytoplasmic spreading does not occur in lymphocytes.

Answer 7

TRUE

Cytoplasmic spreading does not occur in lymphocytes.

Question 8

Plasma cells derive from small _____ lymphocytes

Answer 8

B lymphocytes

Question 9

The characteristic feature of plasma cells

Answer 9

Abundant cytoplasmic and secretory Ig

Question 10

TRUE OR FALSE

A fully mature plasma cell has surface Ig expression.

Answer 10

FALSE

A fully mature plasma cell lacks surface Ig expression.

Question 11

Large electron-dense inclusions of plasma cells

Answer 11

Russell bodies

Question 12

What is the cell being described:

Cell with characteristic basophilic cytoplasm and an eccentric nucleus; large paranuclear zone

Answer 12

Plasma Cell

Question 13

The large paranuclear zone of plasma cells corresponds to

Answer 13

Golgi apparatus

Question 14

Antigens restricted to cells of the B lineage

Answer 14

CD20, CD22, and Pax 5

Question 15

A transcription factor that is a “master regulator” of B-cell development

Answer 15

Pax 5

Question 16

The target of rituximab, a monoclonal antibody commonly used for treatment of B-cell neoplasms

Answer 16

CD20

Question 17

The best-defined pan–B-cell surface antigen

Answer 17

CD19

Question 18

B cells have distinctive activation requirements and high levels of CD44 and interleukin-5 receptor α

Answer 18

B-1 B cell

Question 19

In addition to the CD antigens and Igs, B cells express the three major histocompatibility complex (MHC) class II antigens: ________________

Answer 19

DR, DP, and DQ

Question 20

TRUE OR FALSE

Many B-cell differentiation antigens are expressed by the mature plasma cell, including CD20, Pax-5, surface Ig, and human leukocyte antigen class II antigens

Answer 20

FALSE

Many B-cell differentiation antigens are NOT expressed by the mature plasma cell, including CD20, Pax-5, surface Ig, and human leukocyte antigen class II antigens

Question 21

Distinctive cell surface antigens of plasma cells

Answer 21

CD138 and CD38

Question 22

Clonal plasma cells usually aberrantly lack expression of _____________

Answer 22

CD19 and CD27

Question 23

TRUE OR FALSE

All lymphocyte progenitors originate in the marrow, but T lymphocytes have their own special organ for maturation—the secondary lymphoid tissue —whereas NK cells appear to differentiate in thymus

Answer 23

FALSE

All lymphocyte progenitors originate in the marrow, but T lymphocytes have their own special organ for maturation—the thymus—whereas NK cells appear to differentiate in secondary lymphoid tissue

Question 24

Both CD4 and CD8 contain:
CD2, CD3, CD4, CD5, CD7, and TCR α/β

Antigens specific to:
CD4:
CD8:

Answer 24

Antigens specific to:
CD4: CD10, CD25, CD57 and Foxp3100

CD8: CD16, CD56, CD57, cytolytic enzymes101

Question 25

NK cells are negative for

Answer 25

CD3, TCR (α/β or γ/δ)

Question 26

γ/δ T cells are negative for

Answer 26

CD4

Question 27

Three general stages of thymocyte maturation based on the surface CD4 and CD8 expression:

Answer 27

* Double negative- least-mature ( subcapsular area) * Double positive * Single positive- most-mature (medulla)

Question 28

Surface antigens present on T lymphocytes of all stages

Answer 28

CD2, CD5, and CD7

Question 29

“double-negative” thymocytes also express Aside from CD2, CD5 and CD7

Answer 29

CD1a, cytoplasmic CD3, and terminal deoxynucleotidyl transferase (TDT)

Question 30

Most common lymphocytes in blood

Answer 30

Mature helper T-cells

Question 31

TRUE OR FALSE Mature T cells express either CD4 or CD8, but not both

Answer 31

TRUE Mature T cells express either CD4 or CD8, but not both

Question 32

CD4 recognizes MHC ____ CD8 recognizes MHC ____

Answer 32

CD4 recognizes MHC class II CD8 recognizes MHC class I

Question 33

Coreceptors for HIV

Answer 33

CD4 CCR5 (CC chemokine receptor type 5) CXCR4 (CXC chemokine receptor type 4)

Question 34

Cells that induce immune tolerance, and follicular T-helper cells that promote B-cell maturation and differentiation in germinal centers

Answer 34

T-regulatory (Treg) cells

Question 35

Treg and follicular T-helper cells (TFH cells) express: ___________

Answer 35

CD10 and CD57

Question 36

Adult T-cell leukemia/ lymphoma expresses both _______and ______ and is associated with marked immunosuppression.

Answer 36

CD25 and Foxp3

Question 37

Has characteristic clonal T cells that express CD10 and CD57 just like TFH cells, and this lymphoma is associated with polyclonal hypergammaglobulinemia and the expansion and proliferation of both B cells and CD21+ follicular dendritic cells.

Answer 37

Angioimmunoblastic T-cell lymphoma

Question 38

Cells that exhibit critical roles in mucosal defense and in autoimmune disease pathogenesis.

Answer 38

T-helper-17 (TH17) cells

Question 39

TRUE OR FALSE The NK cell is defined as an effector cell that is MHC-restricted and has the capacity for spontaneous cytotoxicity toward various target cells

Answer 39

FALSE The NK cell is defined as an effector cell that is not MHC-restricted and has the capacity for spontaneous cytotoxicity toward various target cells

Question 40

TRUE OR FALSE Most NK cells have LGL morphology . However, not all NK cells have LGL morphology, and not all LGL cells are NK cells. Many are cytolytic T lymphocytes

Answer 40

TRUE Most NK cells have LGL morphology . However, not all NK cells have LGL morphology, and not all LGL cells are NK cells. Many are cytolytic T lymphocytes

Question 41

Human NK cells characteristically express _____ and ______but not TCRα/β or TCRγ/δ, CD3, or CD4.

Answer 41

CD16 (FcγRIII) and CD56

Question 42

Surface antigens of Treg cells

Answer 42

CD3, CD4, CD25, and cytoplasmic FoxP3

Question 43

Predominant phospholipid in the lymphocyte plasma membrane

Answer 43

Phosphatidylcholine

Question 44

A tyrosine kinase in B cells that plays a critical role in signal transduction via surface Ig receptors

Answer 44

Bruton tyrosine kinase

Question 45

Serve as scaffolding for the assembly of kinases and other signaling molecules after antigen-receptor ligation Have no intrinsic enzymatic activity

Answer 45

Adapter proteins EX: B-cell linker protein (BLNK), Linker for activation of T-cells

Question 46

TRUE OR FALSE Plasma cells have a high DNA-to-RNA ratio

Answer 46

FALSE Plasma cells have a high RNA-to-DNA ratio Reflecting the plasma cell’s high-level synthesis of Ig

Question 47

Pore-forming proteolytic enzyme

Answer 47

Perforin

Question 48

Serine proteinases with specific pro-apoptotic activity

Answer 48

Granzymes

Question 49

Cytotoxic lymphocytes possess serine-proteinase inhibitors, termed

Answer 49

Serpins