ARMY MEDICAL SERVICE GRADUATE SCHOOL WALTER REED ARMY MEDICAL CENTER WASHINGTON 12, D.C. INREPLY REFERTO MEDEC=ZIBP 27 March 1953 Professor Joshua Lederberg Department of senetics Colleze of Agriculture University of Wisconsin Madison 6, Wisconsin Dear Dr. Lederberg: Your letter to Larry Weed was forwarded to this Division (Immunology) and the cultures you requested are being sent by sir. Abrams who has charge of our culture collection. At present, the Department of Bacterial Physiolozy of this Division is engaged in a project dealing with some phases of the problem of immunity to typhoid fever. Prior to my arrival here, I spent a short time at Cold Spring Harbor while receiving my degree with Professor Sol Spiegelman at Illinois, and as a result have been devoting the majority of time recently to studies of a psenetic nature with various strains of typhoid, Iwas fortunate enough to spend some time with Dr. Zinder durins the last SAB, meeting discussing your recent paper as well as a few of the problems we were then starting to investirate. Since then we have made some slirsht progress, and after your letter arrived I discussed the situation with Dr. ‘eed and he sugsested that I write, outlining the few results we have obtained. I ain therefore enclosing a synopsis of our general asproach and would very much apvreciete hearing your opinion of our preliminary attempts. If at) all possible in the near future, I would more than welcome an opportunity to visit you at your laboratory for a few days, providing, of course, it could be arranged at your convenience, It is likely that any preparations necessary for my making a trip from here would probably require twc weeks notice on my part. Aside from this detail, I will he very happy to make any arranvements suitable to your wishes, In the meanwhile, if there are any cultures or other material with which we can furnish you, we shall be more than happ:, to do so. Sincerely yours, Kouwe J Marr Louis 5. Baron, Ph.eD. Department of Bacter’al Fhisiole cs Immunolosy Division “2 §. As an afterthought, I might mention that I was a student at Sturvesant High School from 1937-1940, AN ATTEMPT AT THE USE OF PHAGE LYSATES IN GBXETIC TRANSFER Our major interest lies in the fact that although all typhoid strains which contain the Vi antigen are not necessarily virulent for mice, no strain which lacks this factor is virulent for mice. In addition, all strains isolated from huaan oases of typhoid contain this antigen on isolation. With this situation in mind, we have been attempting to uncover a system which would cause transfer of this antigenic component as well as other more observable factors, namely carbohydrate fermentation and drug resistant, eto., between both Vi and nome-Vi strains of typhoid and related organiams,. Binoe we have been actively engaged in thie problem for only a few months, being primarily oceoupled in setting up basio techniques in an attempt to overcome a number of difficulties which we have enesountered, our findings from the point of view of our original objective are as yet somewhat meager. However, I should like to mention some of the encouraging results obteined. Our basic procedure has been as follows: Donor Strain, Salmonella typhosea strain Ty2 possessing the antigenic composition Vi, IX, XIls, d xylose positive, streptomyoin resistant, can be lysed by its speoific Vi phage known as phage Ey. (This strain oan be lysed by same of the Vi group phages which alae lyse other Vi strains, however, phaze B fails to lyse any receptor strains, Reesptor Culture. Salwonella typhosa strain 645 possesses the identical antigenic structure as strain Ty2 but is streptomycin sensitive and xylose negative; this strain is lysed by the Vi group phages but not by Vi phage Eye A lysate of the donor culture is prepared in mitrient broth, phage By on strain Ty2, X°, 8° and filtered through a UF sintered glass filter. The filtrate is ahecked for sterility and assayed for phage count (usually about 4 x 10° phage partioles/al). The receptor oulture, strain 643 X°, 8° is then incubated with the phage filtrate from the donor strain, with nutrient broth as well as boiled filtrate as controls, After a short inaubation period, the suspenaions are washed and taken up in a few oo of saline end assayed for count/al, usually 10.9 eelte. These suspensions are then plated on Ei! xylose plates and nutrient azar plates overlayed with streptomycin agar. About 10° eslle plated on BMB usually give rise to approximately 1008200 positive cells which my be related to the nuuber of phage particles in the filtrate used to treat the cells. Mo positives are observed on the control plates althoush uninhibited negatives appear on both control and experimental plates, Similar results have been obtained with the transfer of streptomycin resistance, although the results have not been entirely consistant probably due to technical difficulties, We have aleo performed a mmber of absorption experiments and it appears that certain Vi strains will absorb Vi phase Ey rather well without resulting lysis taking place. Such is the case with strain 648 in our xylose and streptomyoin resistance transfer experiments, Howewer, as yet we have been unable to ahow any lysogenicity in either phage treated, phage absorbed or control strains, again possibly due to technical difficulties, At the mment, we are engayed in antigen transfer experiments using these plage lysates on non-wotile Vi strains and non-Vi strains of typhoid. Using semiesolid agar plates, we have noted the presence of spontaneously a So motile variants in the controls of supposedly nonemotile cultures. However, we are in the process of preparing lysates of other unrelated Vi strains such as S. paratyphi C, 8. ballerup and Ee cols 6396/88 using both Vi and 0 phages in an attempt to transduce unrelated flagellar antigens (other than the "da" factor) to our typhoid strains as was demonstrated in your recent paper. He have also been giving some thought to the transfer of the Vi antigen iteelf to non~virulent strains such as 8, typhosa 0-90] and have come to the conclusion that perhaps the mouse would be the best selective agent aesuming that any transduced cell would become virulent.