T2 cells also express BAFF-R, the receptor for the B-cell survival factor BAFF, whose expression is dependent on signals received through the BCR.

As B cells differentiate from the transitional T2 state to full maturity, they raise their levels of mIgD still further, while reducing the expression of mIgM. They also cease to express CD24 and CD93.

TLS Online TPP Program

#Id: 9915

#Unit 4. Cell Communication and Cell Signaling

Intracellular infections are the most difficult for the immune system to detect and eradicate; these can be divided into membrane-bound and cytosolic, with differing key immune response mediators

TLS Online TPP Program

#Id: 9916

#Unit 4. Cell Communication and Cell Signaling

Viral Infections

Virus enters a cell via a cell-surface receptor for which it has affinity and preempts cell biosynthetic machinery to replicate all components of itself, including its genome.

This genome replication step is often error prone, generating numerous mutations.

TLS Online TPP Program

#Id: 9917

#Unit 4. Cell Communication and Cell Signaling

Influenza virus binds to sialic acid residues

Rhinovirus binds to intercellular adhesion molecules (ICAMs)

Epstein Barr virus (EBV) binds to type 2 complement receptors on B cells

TLS Online TPP Program

#Id: 9918

#Unit 4. Cell Communication and Cell Signaling

Innate response elements commonly engaged by encounter with viral PAMPs, such as secretion of type I interferons, inflammasome and NK-cell activation, as well as IL-12 production.

TLS Online TPP Program

#Id: 9919

#Unit 4. Cell Communication and Cell Signaling

Mechanisms of humoral and cell-mediated immune responses

TLS Online TPP Program

#Id: 9920

#Unit 4. Cell Communication and Cell Signaling

Many Viruses Are Neutralized by Antibodies

Antibodies are particularly effective if they are localized at the site of viral entry into the body.