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WROCEAW UNIVERSITY
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$1- _ Wroctaw

an "209786 DECA3 Sey

 

Professcr cr Ceshva Lecerbere
President of the Rockefelter University
Kew Yerk, NY. 16021

Deer Professsor Lecerte

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Meany thanks to you fcr your kind letter of 26 uly that errivecd
after my return frem my helicays trips ta Conferences in Perugia
enc Kelsinki.

From tne infermation you kirncly provided me I supscse that the
strains 679-6£0 had to cerry F plasmic at the begining, end curins
the mutagenisetion. carried out to obtain Thr Leu” auxctrophy,
the strain hes been cured of it.

What concerns my works on Shigella the loss cf type snticen I
with simultenscus acquissiticn of type’anticen III could be concerned
with lisogenic conversion but in this sense thet a phese when
integratec in chrenctcme, ig cocing. for UDP-clucose transferrese.
This enzyme is reenonsible for oresence see ty tats ec sluccee in
secencery sice-cnein in C-snecific nolisaccharic

- AcGlc
E
2
The site of the phage integration have to be near region homologous
to lactose operon of E.coli as Lac* recombinants from crosses
E.coli HfrH x S.flexneri lb are deprived of agglutinability in
type antigen I-specific serum:but are agglutinated by type
antigen III specific serum (Luria and Surrous J. Bact. 74:461 (1957),
Lechowicz, Mulczyk, Malesz:Arch.Immunol. Ther. Expl. 14:405 , (1966).

The of integration or. State of the prophage has to change sponta-
neusly resulting in apparition in 1b serotype cells population,
of mutant with type antigen III ‘which 0 specific polissacharide
hag no longer acetylated glucose in secondary side chain:

r
“Glo NAC 4 Rha —y Rha

The same situation is in Lac” recombinants.

This antigenic mutants arrise spontaneously with the mutation. rate
of 10° erder and,as I mentioned: previously, could be selected:
_Girectly or. indirectly ‘by you replica plate technique using- another.
phage (called F2) virulent for cells with type antigen IT but
unvirulent to those with type antigen TIl. (Lachowicz TM.
Mulezyk.M.: Arch. Immunol., Terapii Dosw. 8: 437 (1960),

Se,the question is what is the state of this phage ‘in the mutant
with antigen formula IIIT; 3, 4,6- arrising in pepulation of. the.
serotype 1b with antigenic formula I; 3,4,6?
‘The antigenic mutant liberate spontaneously. the phage X and this”
phage kils the cells of original lb form. I am sending you by the-
same mail some reprints in which this phenomenon has been described,
The plasmid hypothesis advanced in one of it must be a little
modified in the light of further experiments.
As to the problem of selection cf this antigenic mutant in mice
we actually obteined the results pointing to the serun complement
as the selective factor.
The complement kils selectively cells with type antigen I -+hus
permmiting to master the environement by mutant with type antigen III.
The papar on this subject is actually in preparation to publication.
‘With professor Kunicki-Golcfinger I am in friencly relation.
Ihave the honor to be his stucent. He has been promotor of my
coctor work ., reviaver of my habilitation thesis and proposal
of nominetion on professor post :
Actually he is on pension but still very active in phylosophy of
nature. ;
By the way I'am sending you professor my best season
greeting of Happy New Year .

Yours sincerely

T.M.Lachowicz,