% Cytotoxicity or Relative Cell Damage less than zero - What does it imply? (Sep/08/2008 )

I had spontaneous wells with cells in medium and maximum with cells in NP40. The test samples were cells incubated with serum of different dilutions and complement. At higher concentration of the serum the cytotoxicity looked OK but at extreme dilution, the % Cytotoxicity calculated as percentage of maximum after deducting the spontaneous well value was negative and much below zero.

Does that mean the cells proliferate in such condition?

I had spontaneous wells with cells in medium and maximum with cells in NP40. The test samples were cells incubated with serum of different dilutions and complement. At higher concentration of the serum the cytotoxicity looked OK but at extreme dilution, the % Cytotoxicity calculated as percentage of maximum after deducting the spontaneous well value was negative and much below zero.

Does that mean the cells proliferate in such condition?

Thank U The Bearer.

I do not need to do the proliferation assay for my experiment but was wondering what does that mean.

I did CDC cytotoxic assay in serial dilution of serum but at very low dilution (>1024 X) the % cytotoxicity is negative which means that cytotoxicity in my sample was less than that for 'spontaneous'. So it should mean that the cells died less than it would otherwise die if the serum at that dilution was not there. Am I correct?

Thank U, The Bearer.

I will not be doing those (or in other words - won't be allowed to do as my research does not need to know that). I put the question just out of curiosity and do not expect the find any thing significant there as though the cytotoxicity is below zero, statistically they are not significant. But, I now understand that there can be pro-survival effects. Not sure - what kind though.