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- Cell Markers & Receptors
- OSF - 5
- Pages 63 - 65
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- Definition:
- Cell markers are molecules expressed on the surface of normal cells that
may act as receptors (attachment sites) for other molecules or be unique
markers that help identify a lineage of cells
- Receptors for antigens:
- eAll immune cells except natural killer cells (NK) have molecular
receptors for the recognition of specific antigens
- eExamples of these molecular receptors include:
- ˇT-cell receptors (TCR=s)
- ˇB-cell receptors (BCR=s)
- ¸all are surface immunoglobulins (sIgs)
- ˇCD3 proteins
- ¸work in conjunction with TCR=s
- ˇMajor Histocompatibility Complex molecules
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- Phenotypic markers:
- ethese markers serve to identify and differentiate lymphocytic cells
- eExamples include:
- ˇCD4+
- ˇCD8+
- on THelper or T4 cells
- on TCytotoxic or T8 cells
- antigen + MHC class II
- antigen + MHC class I
- Fc receptors:
- ethese receptors located on surface of some cells serve as attachment
sites for the Fc portion of immunoglobulins
- eExamples include:
- ˇFc(R I
- ˇFc(R II
- ˇFc(R III
- also called CD64
- also called CDW32
- also called CD16
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- Biological responses to Immunoglobulins binding to Fc receptors include:
- ephagocytosis
- eendocytosis
- erelease of inflammatory mediators
- eenhanced antigen presentation
- eremoval of stimulating antigen from immune system
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- Complement receptors:
- emolecules located on the surface of some cells act as attachment sites
for various components of the complement system
- eCategories of receptors:
- ˇfragments of C3
- ˇC3a and C5a
- ˇregulatory receptors
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Notes
