June 11, 1974

Dr. David Boettiger
Imperial Cancer Research Fund
  Laboratories

P.O. BOX 123,468
Lincoln' 8 Inn Fields
London, WC2A 3PX
ENGLAND

Dear David:

It was good to see you last week and to get a chance to compare notes.
read your manuscript and think it is very good;  I have not been asked to review
it, but I cannot imagine it will emcounter any difficulties.
minor suggestions: on page 1, your account of our experiments might be clearer
if you indicated (1.21) that infections were done with B77 rescued from mammalian
cells; on page 2, there is a rnieprint in the third line (Et+), and it would be
better to refer to "nucleic acid hybridization atudies" in the 6th line from
bottom;  in Table 5 is there some reason for the 2 log differences in titres?
Would it be useful to list the VSV pseudotype data for these strains? (do you
have such data for viruees rescued from the R'T- cells?)  I (pm not completely
content about calling your clones RY, since I would not be surprised to find
that there are infected cells, hearing some or all of the RSV genome,  from which
virus cannot be rescued.
of infected, non-transformed cello (which is what I call the general class):
RV, R-T, and R-T with only a partial genome.  Irb there some reason why you
do not cite Kotler's work?  I am smre we agree it is not very satisfying, but
it doesn't cost much to avoid his ire.  Do you think it would be presumptuous
of me to ask whether you would mention in as a personal communication in your
discussion or as a postscript the fact that Peter and I have isolated clones of
3T3 cells similar to your NRK clones.

I have

I do have a few

We would then have two sub-classes (or perhaps three)

We now have three clones in which about 1 copy of RSV DNA has been shown to be
integrated by the network test; in one 6f these (3T3-BS) the Crt1/2 is about
2-3 x lo', three fold higher than in the transformed B77/3T3, i.e., there is
3 fold lese viral RNA.
been carried to sufficient Crt  values to obtain much hybridization, but the
Crt1/2 is certainly greater than 5 x 104.  We have now rescued virus from B5
and B8
rescue is less efficient than with the transformed cell. Interestingly, B4,
from which virus has not been rescued, appears to have less than a full copy
of DNA, thus raising in my mind the possibility alluded to earlier; this aspect
is very preliminary, and requires further examination of subclones, repeat
hybridization and rescue, etc. We have looked at a few subclones, and they breed
true. In addition, we have six additional clones that have RSV DNA, but they have
not been further examined.

In the other two (B4 and B8), the analysis has not yet

using a semi-quantitative adaptation of your procedure; in both cases,

Dr, David Boettiger
June, 11, 1974

Page 2

Let's exchange CSH manuscripts when they are ready.
forgotten about sending ma pur wmmtltropfc RSV.
here for a while In the fall.

I trust you have not
And thfnk about coming

Regards to you and Robin and Steve,  etc,

Yours,

Harold E, V81"a~ts. M.D.
Assistent Prof QssOX
Department of Mlcrobiology

REV: bb