Table II.

pA.1Δ and pE.1Δ CSR in LPS B cells and B cell linesa

CellStimulationPlasmidnbTotalcS/S RecombinantSwitch Frequency (×10−4)dp Valuee
Splenic B cellsLPSpA.1Δ29,0001314.4
pE.1Δ459,800233.8
1.B4.B6pA.1Δ383,100202.4
pE.1Δ6101,950202.0
I.29 μpA.1Δ732,050144.4
pE.1Δ531,45092.9
M12fpA.1Δ872,20020.3g
CD40L734,800195.5<0.001
LPS+ CD40L+ IL4849,65010.2NS
pE.1Δ887,25010.1h
CD40L558,60010.2NS
LPS+ CD40L + IL4866,744152.3<0.001
A20pA.1Δ445,03830.7g
CD40L470,10000NS
TGFβ+ CD40L428,100196.8<0.001
IL4+ CD40L419,200168.3<0.001
pE.1Δ379,90020.3h
TGFβ+ CD40L560,70050.8<0.005
IL4+ CD40L749,80030.6NS
  • a Plasmids were transfected into the indicated cells. DNA recovered from nuclei of the transfected cells was either left untreated or digested with EcoRI and then transformed into bacteria. Miniprep DNA was prepared from the EcoRI-resistant colonies and analyzed by restriction mapping to identify S/S recombinant plasmids.

  • b Number of individual experiments.

  • c The total number of transformants obtained by transforming the bacteria with untreated DNA.

  • d Switch frequency was obtained by dividing the number of S/S transformants by the total number of transformants and multiplying by 104.

  • e The p value indicates the confidence level that the plasmid switch frequency in the stimulated cells was significantly different from that obtained in unstimulated cells. Values of p were derived by χ2 analysis.

  • f Unstimulated cells.

  • g Reference switch frequency for χ2 analysis of pA.1Δ.

  • h Reference switch frequency for χ2 analysis of pE.1Δ.