while we could thus detect , in naive mice , neither positive nor negative selection of the cells from the time of their generation in the bone marrow until their arrival in the periphery , negative selection is in principle possible : the presence of microgram amounts of anti-idiotope antibodies during maturation from pre-b to b cells specifically blocks the appearance of idiotope-bearing lps-reactive cells in vitro .
C1292769
pre-b
C0004561
b cells