GA levels in plants are correlated with stem length, internode elongation and seed germination

TLS Online TPP Program

#Id: 1765

#Unit 4. Cell Communication and Cell Signaling

The possibility of damage from self-reactive lymphocytes is further limited by the life span of activated lymphocytes, which is regulated by programs that induce cell death (apoptosis).

TLS Online TPP Program

#Id: 1766

#Unit 4. Cell Communication and Cell Signaling

Activated T cells express increased levels of Fas and FasL. In both B and T cells, engagement of Fas by FasL induces a rapid apoptotic death known as activation-induced cell death (AICD).

TLS Online TPP Program

#Id: 1767

#Unit 4. Cell Communication and Cell Signaling

Tolerogens- Antigens that induce tolerance

TLS Online TPP Program

#Id: 1768

#Unit 4. Cell Communication and Cell Signaling

Factors that promote tolerance rather than stimulation

a. High doses of antigen

b. Long-term persistence of antigen in the host

c. Intravenous or oral introduction

TLS Online TPP Program

#Id: 1769

#Unit 4. Cell Communication and Cell Signaling

Absence of adjuvants

a. Low levels of costimulation

b. Presentation of antigen by immature

TLS Online TPP Program

#Id: 1770

#Unit 4. Cell Communication and Cell Signaling

CD28 on the T cell and CD80/86 (B7) on the APC provided the costimulatory signal required for T-cell activation.