Uses chemicals to alarm in case of infection. Causes redness, swelling, heat(fever), and pain.
- Mast cells in connective tissue send out histamine molecules. Causes vasodilation (creates redness and heat at site of injury). Heat increases the cells metabolic rate=faster repair.
- Other inflammatory chemical signaling molecules include fatty acid prostaglandins, kininogen, and other plasma proteins, complement blood proteins and cytokines (CD8).
- Histamine and other inflammatory chemicals also increase the permeability of blood vessels, causing nearby capillaries to release protein-rich fluids, that causes swelling. The leaked protein helps clot blood and form scabs, while lymphatic systems sucks up and filters that extra fluid, thus cleaning it before in enters back into the bloodstream.
Local phagocytes and lymphocytes escape leaking capillaries and help destroy pathogens and cleaning up dead-cell.
Best activating cell is dendritic cells, then comes macrophages, monocytes (that turn into macrophages) and the least effective activator is B cells, that only activate itself.
Gives increased glucose uptake, activation of the actin system and gene transcription, which leads to cell cycle.
Within the immune synapse formed between APCs and T cells, three signals are required for antigen-specific T cell activation. Signal 1 comprises the presentation of antigen peptide, in the context of MHC molecules, which is recognized by the antigen-specific TCR. Signal 2 involves the stabilization of the synapse through adhesion molecules and the generation of signals via costimulatory molecules present on the surface of APCs and T cells. CD80/CD86 on APCs interact with their receptor, CD28, on T cells to generate activatory signals, while interaction with cytotoxic T lymphocyte-associated protein 4 (CTLA4) generates inhibitory signals (not shown). Signal 3 is produced by the secretion of cytokines by APCs, which signal via cytokine receptors on T cells in order to polarize them toward an effector phenotype. Ag, antigen.
9th EditionCain, Jackson, Minorsky, Reece, Urry, Wasserman 5th EditionCharlotte W. Pratt, Donald Voet, Judith G. Voet