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Basophils and mast cells and their importance in immune responses. Mast cells. Mucosal mast cells - in the mucous membranes of respiratory and gastrointestinal tract, produce histamine, serotonin, heparin, tryptase, leukotriene C4 ..., participate in parasitosis and allergy
Mast cells can be stimulated to degranulate by:
to IgE on highaffinnity Fc receptor for IgE (FcRI)
*Is a summary of physiological responses to breach the integrity of the organism, leading to protection against infection of damaged sites, localization of damage and healing.
* The first signals to the development of inflammatory responses come from mast cells, phagocytes, and the substances released from damaged cells and extracellular components of matter.
Localinflammation-increased permeability ofbloodvessels (vasoactiveamines, complementcomponents C3a, C5a, leukotrienes ..., swellingatsiteofinflammation) - increasedexpressionofadhesionmolecules on endothelia- activationofcoagulation, fibrinolytic, kinin and complementsystem- influence oflocal nerve endings (prostaglandins, pain) - changes in temperature (IL-1, IL-6, TNF, prostaglandins)
- increased synthesis of protease inhibitors ( macroglobulin)
- leukocytosisSeptic shock - the massive penetration of microorganisms into the bloodstream(TNF) Anaphylactic shock- basophil degranulation and complement activation with allergen (histamine)
- elimination of damaged cells with phagocytes - activation of fibroplastic mechanisms - activation of angiogenesis - regeneration and tissue remodeling
T cell:TCR - antigen-specific receptor (signal 1)CD4 or CD8 - coreceptor (MHCgp binding)CD 28 - costimulatory receptor (signal 2, binds CD 80, CD 86)CTLA-4 - inhibitory receptor (binds CD 80, CD 86)CD-40LAPC:MHC gp I + antigenic peptideMHC gp II + antigenic peptideCD 80, CD 86 - costimulatory ligandsCD 40
The same antigen can induce an active immune response or an active state of tolerance, the result of response depends on many factors:
( Individual has 3 cell surfaceisotypesof HLA molecules (HLA-A,-B,-C) mostlyin 2 differentalelicforms )
1) Serotyping - Microlymfocytotoxic test
Allospecific (typing) serums (obtainedfrommultiplenatal to 6 weeksafterbirth, orcommerciallypreparedsetsoftypingserums (monoclonalantibodies))
- thepercentageofdeadcellsis a measureofserum toxicity (forces and antileukocyteantibody titre)
Positive reactionisconsidered more than 10% deadcells(serologicaltypingcanbe done also by flowcytometry)
2a) PCR-SSP= Polymerasechainreactionwithsequentialspecificprimers
The most accuratemethodof HLA typing.
Wegettheexactsequenceofnucleotides, whichcompareswith a database ofknownsequencesof HLA allels