Touchdown  PCR is initiated at very high annealing temperatures, which allow only perfectly matched primer-template DNA hybrids to form and support amplification. The annealing temperature is dropped in a stepwise fashion with each cycle of PCR. 

TLS Online TPP Program

#Id: 7243

#Unit 5. Developmental Biology

TLS Online TPP Program

#Id: 7244

#Unit 5. Developmental Biology

B-Cell Development

TLS Online TPP Program

#Id: 7245

#Unit 5. Developmental Biology

B- cell maturation

TLS Online TPP Program

#Id: 7246

#Unit 5. Developmental Biology

T1 and T2 Transitional B Cells

TLS Online TPP Program

#Id: 7247

#Unit 5. Developmental Biology

T1 cells are mIgMhi, mIgD -/lo, CD21-, CD23-, CD24+, and CD93+. 

T2 cells differ from T1 cells in having higher levels of mIgD and in expressing CD21 and CD23. 

TLS Online TPP Program

#Id: 7248

#Unit 5. Developmental Biology

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.