Karteikarten
Lymphocytes
Karten in diesem Stapel (21)
- 1What are the central cells of adaptive immunity?Lymphocytes bearing antigen receptors, which are responsible for its characteristic properties of diversity, specificity, and memory.
- 2What proportion of circulating leukocytes do lymphocytes constitute? Contrastingly, what proportion of lymph cells do they constitute?Lymphocytes make up 20-40% of the body's leukocytes, and 99% of the cells in lymph.
- 3Roughly how many lymphocytes are there in the body?~10^12 (a trillion)
- 4What are the three broad subdivisions of lymphocytic cells?B lymphocytes, T lymphocytes, and natural killer cells.
- 5Which lymphocytes are involved in cell-mediated immunity?T lymphocytes
- 6Which lymphocytes are involved in humoral immunity?B lymphocytes
- 7Which two cell types can B cells mature into?Plasma and memory B cells.
- 8Which four cell types can naive T lymphocytes mature into?T regulatory, T cytotoxic, T helper, and memory T cells.
- 9What is the main function of plasma B cells?To secrete antibody.
- 10What is the main function of B memory cells?To react quickly and specifically to an antigen next time it is encountered by the memory B cells.
- 11When do naive B and T lymphocytes mature?When they are stimulated by interaction with antigen.
- 12Where are most lymphocytes activated?In the lymph nodes, where they proliferate and mature into effector cells.
- 13Describe an unprimed/naive T/B cell.Small (~6μm diameter), motile, nonphagocytic cells which cannot be differentiated from one another morphologically. Their cytoplasm forms a barely discernible ring around their nuclei, they have densely packed chromatin, few mitochondria, and a poorly developed endoplasmic reticulum and Golgi apparatus. The naive lymphocyte is generally thought to have a short life span.
- 14In their inactivated state, which cell cycle phase do B and T lymphocytes remain in?G0.
- 15What do naive T/B cells differentiate into initially, when first interacting with antigen?Lymphoblasts, 15μm diameter cells with a higher cytoplasm-to-nucleus ratio and more organellar complexity than small lymphocytes.
- 16Memory cells look like small lymphocytes. How can they be distinguished?By the presence or absence of certain molecules on their cell membranes.
- 17How can B and T cells be distinguished down an electron microscope?B cells look 'hairy' because of their IgD receptors, whereas T cells look much smoother.
- 18What is the main mechanism for differentiating B and T cells, as well as differentiating the many cells in the different lineages and maturational stages of lymphocytes?Recognition by monoclonal antibodies. All of the monoclonal antibodies (those specific for a single epitope of an antigen) that react wit a particular membrane molecule are grouped together as a cluster of differentiation (CD). Around 250 CD markers have been described for human lymphocytes.
- 19Which type of T lymphocyte is a CD4+ lymphocyte?A T-helper lymphocyte.
- 20Which type of T lymphocyte is a CD8+ lymphocyte?A T-cytotoxic lymphocyte. Variably, natural killer cells can possess CD8+ antigenic epitopes.
- 21Which type of lymphocyte possesses CD21 antigenic epitopes on its cell membrane?B lymphocytes
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- From the 27-09-13 Immunology and Disease lecture.
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