Lymphocytes Flashcards
Lymphocytes
cells responsible for adaptive immune responses
Types of Lymphocyte
- innate lymphoid cells that play a role in innate immunity
- T cells that regulate adaptive immunity and are responsible for cell-mediated immune responses
- B cells that are responsible for antibody production
Lymphocyte Structure
small round cells that each contain a single large round nucleus.
Can lymphocyte populations be differentiated?
no, lymphocyte populations cannot be differentiated by shape, size, or morphology.
What Lymphocyte can be differentiated?
Innate lymphoid cells are larger than T or B cells
Where are lymphocytes found?
in lymphoid organs, lymphatic fluid, blood, lymph nodes, spleen, bone marrow, and intestinal tract
Where are B cells Not found?
in tissue. They stay in lymph node, spleen, or bone marrow
Where are B and T cells produced?
in the bone marrow
Where do T cells mature?
thymus
Where do B cells mature?
bursa, Peyer’s patches, or bone marrow
Innate Lymphoid Cells
are present all the time, do not have adaptive antigen recognition receptors. They detect PAMPs and are stimulated by cytokines. They are functional and available before T cells can be generated
ILC3 Cells
produce IL-22 in response to IL-23. They also produce IL-17 and GM-CSF that initiate the inflammation process. Important in regulating inflammation under epithelial surfaces. Important in regulating responses to the microbiota
Where are B cells found?
- the cortex of lymph nodes
- in follicles with the Peyer’s patches and spleen
- in the marginal zone of the white pulp of the spleen
What percentage of blood lymphocytes are B cells?
10-40%
Lymphocyte Surface Molecules
given a cluster of differentiation (CD) designation
designation of helper T cells
CD4
designation of cytotoxic T cells
CD8
B Cell Antigen Receptor
subpopulations of B cells use gamma, mu, alpha, epsilon, and delta in their BCRs. Are shed from the B cell in large amounts into tissue fluid and the blood, where they are called antibodies.
What are antibodies
soluble BCRs
Fc Receptors
for immunoglobulins for feedback
Complement Receptors
for regulation
Cytokine Receptors
for co-stimulation and regulation
Where are T cells found?
- paracortex of lymph nodes
- periarteriolar lymphoid sheaths of the spleen
- interfollicular areas of the Peyer’s Patches
What percentage of blood lymphocytes are T cells?
60-80%
What are the two populations of T cells?
- paired alpha and beta peptide chains
2. paired gamma and delta chains
What is found on all T cells?
CD3
CD4
receptors for MHC class II molecules on antigen-presenting cells.
CD8
receptors for MHC class I
Complement and Cytokine TCRs
for co-stimulation and regulation
Complement Receptors
CR1 to CR4
CR1
expressed by B cells and activated T cells. CR1 binds C3b and C4b
CR2
expressed by B cells and activated T cells. It bind C3d and C3bi. Closely associated with the BCR and regulates B cell responses to antigen
What do NK cells express?
CR3 and CR4
Adherence Molecules
regulate signal network transmission between the cells of the immune system and control the movement of leukocytes in tissues.
What are the cell adhesion molecules found on lymphocytes?
integrins, selectins, and members of the immunoglobulin superfamily
Integrins
heterdimeric proteins formed by alpha and beta chains. Allow leukocytes to bind to blood vessel walls. Allow helper cells and other cell types to bind together and interact
Immunophenotyping
identify T and B lymphocytes based on CD molecules on surface.
Immunofluorescence
make specific antibodies to the cell surface protein of interest. Conjugate a fluorescent dye such as FITC to these antibody molecules. Mix them with the cells and then wash to remove unbound antibodies. Use flow cytometer.
Horse Lymphocytes
EqWC1- 70% of equine T cells, 30% of B cells, 50% of granulocytes
EqEC2- found on granulocytes and most T cells
Bovine Lymphocytes
BoWC1 through BoWC15
Pig Lymphocytes
SWC1 to SWC9
List adhesion molecules found on the surface of lymphocytes
integrins, selectins, and members of the immunoglobulin superfamily
