18 Questions
Which cell type is characterized by the presence of surface antigens CD19, CD45R, CD43, CD24, and c-Kit?
Pre-B cell
What additional immunoglobulin appears on the surface of Mature B cells besides IgM?
IgD
Which receptor allows NK cells to attach to and lyse cells coated with antibodies?
CD16
What is the function of LAK cells?
Lysing tumor cells with the help of IL-2
Which immunoglobulin is confined to the cell surface in its membrane-bound form?
IgM
What is a characteristic of the Immature B cell?
Light chain genes rearranged
Which cells express surface immunoglobulin receptors and lyse target cells by ADCC?
K cells
What is the main function of macrophages in relation to antigens?
Acting nonspecifically by ingesting and destroying bacteria or tumor cells
Which identifying marker is characteristic of Activated B cells?
CD25
Which antigen receptor mediates interactions between effector and target cells?
CD56
When B cells are activated and transform into blasts, what will they give rise to?
Plasma cells and memory cells
What is the role of CD16 on NK cells?
Attach to and lyse antibody-coated cells
Where do Peyer's patches, tonsils, and appendix belong in the classification of lymphoid tissues?
MALT
What do proteins on cell surfaces help differentiate between?
T cells and B cells
Which cell type is the main component of the secondary lymphoid organs?
Effector lymphocytes
Which stage of T cell differentiation involves thymocytes lacking CD4 and CD8 markers?
Double negative stage
Where do LAK cells and K cells primarily function?
Secondary lymphoid organs
What is the main function of macrophages in the lymphatic system?
Phagocytosis
Study Notes
B Cells
- Pro-B cells have distinct markers: CD19, CD45R, CD43, CD24, and c-Kit.
- Pre-B cells are characterized by immunoglobulin gene arrangement and the appearance of heavy chains in the cytoplasm.
- Immature B cells have light chain genes rearranged, and light chains appear in the cytoplasm, forming IgM when coupled with heavy chains.
- Mature B cells exhibit IgD on their surface, along with IgM.
- Activated B cells exhibit markers like CD25, which is a receptor for IL-2, and transform into blasts that give rise to plasma cells and memory cells.
Natural Killer Cells (NK Cells)
- CD16 is a receptor for the Fc portion of IgG, allowing NK cells to attach to and lyse cells coated with antibody.
- CD56 mediates interactions between effector and target cells.
LAK Cells and K Cells
- LAK cells are lymphokine-activated killer cells that use IL-2 to help lyse tumor cells.
- K cells express surface immunoglobulin receptors and lyse target cells by ADCC (Antibody-Dependent Cellular Cytotoxicity).
Macrophages
- Phagocytic cells that act nonspecifically, ingesting and destroying bacteria, damaged host cells, or tumor cells.
- Macrophages "process" antigen (as do T lymphocytes) before presentation to B lymphocytes.
- Destroy target cells by phagocytosis (in lymph nodes and spleen) and direct cytotoxic effects on antibody-coated cells.
Secondary Lymphoid Organs
- Main function: filtration, where lymph fluid flows slowly through spaces called sinuses, lined with macrophages, creating an ideal location for phagocytosis.
Other Lymphoid Organs
- MALT (Mucosal Associated Lymphoid Tissue) includes gastrointestinal, respiratory, and urogenital tracts.
- MALT is important for immunoglobulin A production and development of tolerance to ingested antigens.
- Peyer's patches are a specialized type of MALT located at the lower ileum of the intestinal tract.
Surface Markers on Lymphocytes
- Proteins that appear on cell surfaces can be used as markers to differentiate T cells and B cells.
- Proteins can also be used to distinguish the developmental stages of the two types of cells according to when they appear.
Cells of the Immune System
- T cells are the chief lymphocytes in blood and lymph, have a long life span, and are thymus-dependent.
- Double negative stage: early thymocytes lack CD4 and CD8 markers.
Learn about how CD16 plays a crucial role in bridging the innate and acquired immune responses to various pathogens and target cells, including tumor cells, embryonic cells, bone marrow cells, thymus cells, and microbial antigens.
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