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Molecular Diagnostics > Module 4 > Flashcards

Module 4 Flashcards

1
Q

what are the adaptive immune systems

A

humoral and cellular with two classes of specialized cells

t lymph and b lymph (becomes plasma cell) that form from a stem cell

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2
Q

what do lymphocytes do

A
  • recognize foreign antigens
    -directly destroy some cells
    -produce antibodies as plasma cells
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3
Q

what are the primary and secondary lymphoid tissues

A

primary: thymus , bone marrow -fetal liver

secondary - spleen, lymph nodes, peyers patches in the intestine

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4
Q

what is the function of the thymus

A
  • t cell development
    -in the lymphatic system
    -as you age the thymus changes
    reduction in thymus production of naive cells
    -intrinsic defects in mature T cell function
    -life span on naive T cells and memory T cells are altered-decline in T cell response in older people
    -increased susceptibility to infections, autoimmune disease and neoplasms
    -shrinks in size as you age
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5
Q

what is the role of the thymus in t lymph maturation

A

-lymphocytes travel from bone marrow to thymus to mature and become specialized
- the thymus is part of the endocrine system (production and release of hormones)
- regulates immune function secreting soluble hormones
- secretes thymosin- helps make specialized t cells (proliferation and differentiation)
-secretes thymocytes - immature t cells have acquired membrane antigens (from bone marrow and to the thymus to mature)

-the reticular structure of the thymus allows lymphocytes to pass through it and into the bloodstream -
-phagocytosis kill immature cells and any viable cells migrate to secondary tissues

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6
Q

what happens if there is an absence in thymus development

A

-causes t lymph deficiency
-presents as changes in immune system

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7
Q

if there is abnormal thymus development

A

there is a dysfunction of t and b lymph
-increases autoantibodies and monoclonal gammopathies

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8
Q

what is the function of the bone marrow

A

-contained in spongy bone
- source of progenitor cells
- can differentiate into lymph and other hematopoietic cells

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9
Q

what are the secondary lymphoid tissues

A
  • lymph nodes
    • have a lymphoid filter and replenish lymph fluid

spleen
-filters blood by removing cellular waste and old white blood cells

-gut associated lymphoid tissue (GALT)
- peyers patches (pre B lymph) in intestines and liver
-help with lymphocyte recirculation

-thoracic duct
- the thoracic duct lymph -rich source of mature T cell

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10
Q

secondary lymph tissue

A

bronchus associated lymphoid tissue - BALT
-secondary lymph tissue in lower respiratory tract -inhaled
antigen

-skin associated lymphoid tissue
- antigens introduced through the skin are presented by epidermal cells
- epidermal cells interact with lymphocytes in the skin and drain lymph nodes

blood
- mature lymph circulate there

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11
Q

where are t cells distributed

A

-perifollicular and paracortical regions of lymph nodes
-medullary cords of lymph nodes
-periarteriolar regions of the spleen
-thoracic duct of circulatory system

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12
Q

where are b cells distributed

A

b cells multiply and populate

follicular and medullary (germinal) centers of the lymph nodes
-primary follicles and red pulp of the spleen
-follicular regions of the GALT
-medullary cords of the lymph nodes

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13
Q

what is the function of the secondary lymphoid tissue

A
  • allow migration and interaction between antigen presenting cells (APCs) T and B lymphocytes, follicular dendritic cells (FDCs) and other stromal cells
    - generation of humoral immune responses
    • proliferation of B/T cells in 2ndary lymph tissues is dependent on antigenic stimulation

-tumor necrosis factor TNF and lymphotoxin
- both are cytokines produced by T and B lymph are essential to formation/maintenance of secondary organs

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14
Q

how do T cells mature

A
  • bone marrow progenitor cells mature in the thymus
    -differentiation of T lymph starts in the thymus as thymocyte (immature T cell) with early surface markers - CD44 and CD25 that commit them to a cell linage (these two are from t cells)
    -as thymocytes develop genes for antigen receptors are rearranged
    -
    -maturation takes 3 weeks when cells filter through thymus cortex to medulla and then enter through blood circulation
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15
Q

what do you find in the blood circulation

A
  • mature T lymphs which can survive for months or years but the average life of B lymp is a few days

-naive lymphs that have not met their antigen

-memory cells - older t cells or B cells that were stimulated by antigen

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16
Q

what are the types of T cells

A

naive t cells - not encountered their antigen

regulatory t cell - prevents autoimmune disease, modulates the immune system

memory t cell - heightened response after being REintroduced to a pathogen

T helper - with CD4 helps other lymphs to mature and activate

T killer - CD8 destroy virus infected cells and tumor cells

17
Q

what are CD markers

A

Cluster of differentiation

-surface markers that identifies a cell line

CD4 - MHC CLASS 2 HELPER FUNCTION
CD8 - MHC CLASS 1 CYTOTOXIC FUNCTION - KILLER T CELLS

18
Q

T CELL maturation cells

A

cd 44- increases activation of t cells

cd25 - t cell proliferation

early thymocytes dont have cd4 or cd8 and are called double negative thymocytes -outer cortex of thymus under interleukin 7 -growth and development

-rearrangement of gene for antigen receptor and beta chain create CD4 and CD8 thymocyte

19
Q

what are double negative thymocytes

A

-dont have t cell receptors- CD4/CD8

-interleukin 7 needed for growth and differentiation
-can develop beta, gamma, and delta chains depending on their genetic makeup. The presence of the chains classify thymocytes are negative or positive and help regulate immunity

-people with increased CD4 and CD8 NEGATIVE (double negative lymphs) are those with autoimmune diseases, graft vs host disease (LOTS OF IMMATURATION)

20
Q

what are double positive thymocytes

A

cells with both CD4 and CD8 POSITIVE

-increased double pos thymo indicative of inflammatory diseases , viral infections and cancer

21
Q

what are helper T cells

A

Th1 - cell mediated effector mechanisms
Th2- regulation of antibody production
Treg (regulatory T cells) immunoregulatory type of Th cell

22
Q

What are cytotoxic T lymph

A

capable of directly destroying virally infected target cells
-bind to infected cell antigen and use perforin or granzyme to make pores and cause cell death and apoptotic bodies

-suppressor T lymph - down regulate the action of other T and B cells

23
Q

what NK cells

A

-lyse virus infected cells by antibody dependent cellular toxicity
-respond to CD markers

-granzymes -serine proteases released by granules in the cytotoxic t cells and NK cells

how are they different than cytotoxic t cells
- how they recognize their target - NK attack cells even if there is no surface marker but cytotoxic t cell need a surface marker to recognize their target and bind

24
Q

what is the ration of help t to suppressor t

A

2:1

changes as you get older
-decrease in suppressor cells and increase in helper cells

-t cell subset type changes in the blood but the total number of t cells stays the same

issues with cell mediated immunity
impaired humoral response due to cytokine production impairment

igM decreases but igA IGG increases

25
Q

what are the functions of t lymph

A
  • t cells are helps by antigen presenting cells APCs
    -there are two pathways that APCs take up the antigen and present to lymphocytes
26
Q

what is the endogenous pathway

A

-endogenous antigens generated in the APCs and presented on the membrane with MHC class 1 modules

27
Q

what is the exogenous pathway

A

-exogenous pathway antigens are taken up by endocytosis and presented on surface with mhc class 2

-activates helper T cells which cytokines to stimulate b cells to be plasma cells to make AB

T cell receptor helps t cell interact with specific peptide

t cells recognize the protein antigen by peptide fragments on the cell surface by either mhc class 1 or 2

28
Q

t cell activation leads to

A

proliferation
differentiation
production of cytokines
development of effector function

29
Q

what is the function of B lymphs

A

-AB production
-antibody independant pathogenic role - presents antigens
-expand clonally - dominant APCs
-produce cytokines and chemokines - signal immune effector cells

subsets
B1 - CD 5 marker - self renewing set- responds to common microbial antigens - generate autoAB

B2 - most of B lymph , antigen receptors, responds to t dependent antigen

30
Q

Plasma cells in the humoral immune response

A

Ab forming cells

-terminally differentiated b cells
-help produce AB which is our primary defense against microorganisms
-help mediate rejection of transplants organ
-antigenic stimulation prompts B cell to multiply

31
Q

what do Plasma cells secrete

A

5 classes of immunoglobins
IGM, IGG, IGD, IGA, IGE

increased - viral disorders -rubella, allergic reactions , collagen disorders

plasma cell dyscrasias: increased plasma cells infiltrate the bone marrow completely -cancers, myeloma , Waldenstroms)

32
Q

what is a primary immunodeficinecy disorder

A

-dysfunction of innate and adaptive systems
-rare genetic disorders

33
Q

what is a secondary immunodeficiency disorder

A

immune deficiency as a result of other disease or condition - malnutrition, chemotherapy drugs

34
Q

what are disorders mediated through immune mechanisms

A

transfusion reactions autoimmune reactions

35
Q

EVALUATION OF IMMUNODEFICIENCY SYNDROMES

A

symptoms - recurrent upper and lower resp like resp tract infections, diarrhea , sepsis

testing - cbc, ptl count esr

screen - immunoglobin testing (PE) , complement testing

additional testing - metabolic testing panel , HIV , sweat chloride , antibody titers

if everything is normal - interleukin deficiency (IRAK), or toll like receptor function assay
- abnormal results = innate immune deficiency

Molecular Diagnostics (13 decks)

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