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Where are B Lymphocytes differentiated at ?
Where are T Lymphocytes differentiated at?
Thymus through antigen-independent lymphopoiesis
Name primary lymphoid tissues
Describe a lymphoblast
- 1 or more nucleoli
- Dark blue cytoplasm
- No cytoplasmic granules
Describe a prolymphocyte
- 0-1 nucleoli
- Basophilic cytoplasm
- No cytoplasmic granules
Describe a lymphocyte
- Scant to moderate amount of blue cytoplasm
- Few azurophilic granules
When do reactive lymphocytes become activated?
Activated as part of immune response
Describe reactive lymphocytes
- Larger cell
- Increased amount of dark blue cytoplasm (RNA)
- Irregular shaped nucleus
- Irregular shape to the cytoplasm, indented by RBCs
What are T Lymphocytes dependent on?
What are the membrane markers for T Lymphs?
What are the functions of T Lymphs?
- Cellular immunity
- Graft rejections
- Lysis of neoplastic cells
- Attack/destroy viral and fungal organisms
- Obtain info from monos
- Regulates humoral response by helping antigens activate B cells
- End products of activation are cytokines/lymphokines/interleukins
Name the 3 T cell subsets involved in immune response
- T helper/inducer cell (T4)
- T suppressor cell (T8)
- Cytotoxic T cell (T8)
What T cell is identified by CD4 membrane marker and promotes activation of B cells by antigens?
T helper/inducer cell (T4)
What T cell is identified by CD8 membrane marker and suppresses activation of B cells by antigens?
T suppressor (T8)
What T cell is identified by CD8 membrane marker and functions in viral infections and organ rejections?
Cytotoxic T cell (T8)
What is the normal T4:T8 ratio in the circulating blood?
What clinical condition monitors the T4:T8 ratio?
- HIV patients
- HIV destroys T helper (CD4) cells, which decreases the ratio as the infection spreads
What are B Lymphs dependent on?
Dependent on antigenic stimulation
What membrane markers identify B Lymphs?
What happens when foreign antigens stimulate B Lymphs?
- Stimulates B Lymphs to become reactive lymphs
- Reactive lymphs transform into immunoblasts, then into plasma cells that produce antibodies to provide humoral immunity
What cell is the end stage of B lymphs, dominant in lymph nodes, and not normally seen in circulation?
Describe plasma cells
- Abundant blue cytoplasm with prominent perinuclear (golgi) zone
- Eccentric nucleus with a very coarse, clumped chromatin pattern
What cells lack B cell or T cell membrane markers, are CD16 and CD56 positive, and responsible for surveillance of cells for surface alterations such as tumor cells or cells infected with viruses?
Natural Killer (NK) / Large Granular Lymphocytes (LGLs)
What are Natural Killer (NK) / Large Granular Lymphocytes (LGLs) activated by?
IL-2 to express nonspecific cytotoxic functions
How do Natural Killer (NK) / Large Granular Lymphocytes work?
Attack antigens with attached IgG - called antibody dependent cytotoxic cells
Lymphs >50%, with 20% reactive T Lymphs attacking the affected B lymphs
Heterophile antibody test POS
Agent infects B lymphs
Transmitted through nasopharyngeal secretions
90% of Lymphs can be reactive
Negative heterophile antibody test
Transmitted by Blood transfusion and Saliva exchange
After 12-21 day incubation period, symptoms appear and include vomiting, fever, rash, diarrhea, and possible CNS involvement
Lymphocytosis with no reactive lymphocytes
Associated with Adenovirus and Coxsackie A virus
Name some other conditions associated with viral lymphocytosis
Name some other conditions associated with nonviral lymphocytosis
- Bordetella pertussis (whooping cough)
Name what cells are indicated with the following CD markers: