November 19, 1952

-' Dear Dr. Edwards:

Iam writing again without having given you a ehance to reply to ay
previous letter because of the occurrence of some very anomalous resulte
in a recent trensducticn axperiment, on whieh 7 need your helo.

I have been studying the genetia behavior of your $157, "S. paratyphi B",
monophasic, phaee 2, In ay hands this appears to be atrictly monophasic, al~
though we have not done very intensive selections as yet, The theory that
hae been developed from our previous studies igathat tha detarninantes for
phase 1 and phase 2 ratyakated to two dintinct lot, A and Ans Thus, the
genetic actuation for typhiauriua would be: a” An. This does not say
very much excert that in transduction expsrimants, ohnee~-l factors are autually
axclisive and phase-2 factors likewiss. It 42 of sourse contistent with the
aistribution of group and specific antigens in the diagnostic scheme. #157
appeared to be anomalous, however, in that ites 1,2 phase was tranaducible
to monophasic~l types such 25 8. typhi an? scnophasic 9. varatyphi B PKA 248,
thevrosult being what sppeared to be a replacement of ¢ or b, resp., with
~~1,2, Other 1,2 phases, of diphasic types, do not behave this way.

In 2 further study ef this situstion, PA (shony em: chase) was transduced
to #157, 1.6., brenx --K ~:1,2 . I should not have been surprised to have

replaced the 1,2 by enx, that is to nave substituted Ag 2 but

the resulting stock appears to be rather the anomalons snarl, 2 1 This would
bs dn Line wlth the notion that #157 Instesd of being 4,7 A 2 4@ actually
ia

AS As ; 1.e., that from a genetiw point of view, its 1,2 complex is related

tc the sppeific phases of other organisaa. Hcw such a thing can have come about,
fT sannot imagine, I cannot go much further with this until Lhe serology of the
enx:1,2 is verified. I am enclosing cultures of the two phasas, one cbtained
from the other by serum selection as 33~926 (she) and sw-92% (1,2). In fact,

the enx phase seems also to show a strong reaction with 1,2 despite the fact
that it can be passed through 1,2 serum agar. The dealgratiois 1,2 and enx

are based of reactions with the comlex, unadsoried sera and ins igference as
to their origin. It is obviously off sone importame to verify whether "enx"
means €, ©, ami x or whether its expression has been modified during the trans-
duction from abony to 157. 2

Details on the origin of this strain 157 thus become more urgent. In addition,
for a manuacript on O-H variation, I would appreciate whatever information you
can provide on the history of 4937/50 —4.e., was it first isolated as an O form,
or did 1t appear in the laboratory from a cultures already typed as typhimriun?

Has SW-664 been typed yet, as eh or ene? s?

on a
sor As

Sincerelg,
\ Joshua Lederberg