Cortisol inhibits the production of interleukin-2 and the proliferation of T lymphocytes.

TLS Online TPP Program

#Id: 1932

#Unit 4. Cell Communication and Cell Signaling

The Three Complement Pathways Converge at the Formation of the C5 Convertase. 

TLS Online TPP Program

#Id: 1933

#Unit 4. Cell Communication and Cell Signaling

C5 Initiates the Generation of the MAC

TLS Online TPP Program

#Id: 1934

#Unit 4. Cell Communication and Cell Signaling

C8 is made up of two peptide chains: C8β and C8αϒ. 

Binding of C8β to the C5b67 complex induces a conformational change in the C8 dimer such that the hydrophobic domain of C8αϒ can insert into the interior of the phospholipid membrane. 

TLS Online TPP Program

#Id: 1935

#Unit 4. Cell Communication and Cell Signaling

The C5b component is extremely labile, is not covalently bound to the membrane like C3b and C4b, and is rapidly inactivated unless it is stabilized by the binding of C6.

TLS Online TPP Program

#Id: 1936

#Unit 4. Cell Communication and Cell Signaling

The C5b678 complex can create a small pore, 10 Å in diameter, and formation of this pore can lead to lysis of red blood cells, but not of nucleated cells.

10 to 19 molecules of C9 can be bound and polymerized by a single C5b678 complex. The completed MAC, which has a tubular form and functional pore diameter of 70 Å to 100 Å. 

TLS Online TPP Program

#Id: 1937

#Unit 4. Cell Communication and Cell Signaling

The reaction occurs on an immune complex or other non cellular activating surface, then the hydrophobic binding sites cannot anchor the complex and it is released. Released C5b67 complexes can insert into the membrane of nearby cells and mediate “innocent bystander” lysis.