23 March 1972
Dear Paul,
I am sorry I did not reply to your letter before but I was in fact in the USA when it arrived, and have only now got round to action. However, I did hear from Bill Folk the gist of the results, and in fact mentioned them once or twice in the States. I hope you do not mind.
The results are certainly interesting, particularly in view of the Smith results. I am a little worried that the stable transformant ST-1 had no detectable genome, though this might be the most interesting result of the lot if it turned out in the end that a cell could loose the virus but maintain the transformed phenotype, the only combination which has not yet turned up. Anyway, I agree that more clones should be tested, both of abortives to compare with the Smith results and of stables for reasons above. What we will do immediately is this: Maureen and I have found that we have the following abortive clones in the freezer which are not mentioned in your letter, MA-1, 3, 7 and 10, SA-7 and 11. If these are viable Maureen will grow them up to 5 G quantities and we will send them to you for DNA isolation.  Presumably they should be sent frozen on dry ice. How would you like the cells harvested and suspended before they are frozen?
We will also grow up ST-1 again and send you 5 G for retesting. We will not isolate more clones from methocel cultures until you have the results on these, unless we find that the stocks in the freezer are dead. Later, however, we can set up some more, and if you can come yourself in September we would all be delighted.
One other thing; Jonathan Warner (from Einstein) is collecting abortive SV 3T3 clones and is attempting to rescue by cell fusion with permissive cells. It seems to be going quite well and he has collected quite a large number of clones. The first few have been fused and will be assayed for virus in a few weeks. Once he has some data on the fusion results he would be happy to let you have these clones to test. Could you do this? Have you got the SV 40 system set up as well?
Once again many thanks for all the news, and I do hope that you will come on another visit. Art Pardee will be here also next autumn.
All the best,
Yours sincerely,
Michael