September 22, 1952

Dear Dr. Kauffmann:

I have recently seen your note with Schmid (Acta path. 1952)
on the isolation of a unique strain of Salmonella paratyphi A
with the XII, antigen. If it is not too mech trouble to you, I

a
would appreciate the favor of a subculture of this strain. The
possession @f the XII, component should bring it into our system
of cultures within which our genetic techniques are applicable.
It would appear that these procedures (outlined in an abstract
I recently sent to you, and about to appear in an article in
J. Bact.) should permit the exchange of flagellar factors from
any strain to any other in the XII,-carrying groups. We are currently
working to apply this not4on on a farger scale. £ I wonder if there
are any antigen combinations, corresponding to existing serotypes or
not: that would be of special interest to you. If seg, we will be
glad to attempt it. We are also iotkimtmpdcqmerdmentex starting
experiments to determine whether other Salmonella groups can be
manipulated in the same way. These operations are perhaps laboratory
curiosities, but they perhaps justify the suspicion that recombination
between strains may play some role in the natural generation of types.

If I may make an additional request, I would be most grateful
to be the beneficiary of reprints of your current and continuing
publications on serology of E. coli and Salmonella. Your recent
book has been most Helpful, but it 1s a difficult task to keep abreast
of current developments. Il wa sans dire, I will be most happy to
exchange.

I might mention in passing that our myamx "synthetic" IX XII; i—
strain appears to be strictly monophasic, and should be an ideal antigen
for the production of anti-i sera. We have used it ourselves, and have
sent the strain to Chamblee,Georgia. If it would be of any use to yourself,
I will be glad to forward it.

Yours sincerely

Joshua Lederberg