LETTERS TO THE EDITORS 351

attempted. Such treatment may be a means of isolating viruses or viruslike ma- terial from tumor tissues in which a virus etiology has not yet been established. In fact, as is shown in Table 1, ultracentrifugal fractionation of such antigen suspensions can be utilized to obtain further differentiating information. For instance, Rous viral activity has been associated with particulate material in the size range of 75-150 mp (10, 12), and the complement-fixing activity observed in these experiments is found predominantly in the 20,009rpm pellet, where parti- cles of this size would sediment. The human sarcoma situation, however, appears to be the reverse; the major portion of the activity is associated with the 40,000- rpm pellet, or microsomal fraction. Further quantitative studies of these and other similar antigens are in progress.

REFERENCES

1. GESSLER, A.E., BENDER, C.E., and PARKINSON,~~. C., Trans.N. Y.Bcad. Sci. [Ser. ZZ] 18, 701 (1956).

2. GESSLER, A. E., BENDER, C. E., and PARKINSON, M. C., Trans. N. Y. Acad. Sci. [Ser. ZZ] 18, 707 (1956).

3. HUMMELER, K., and HAMPARIAN, V., Science 126, 547-548 (1957). 4. HAMPARIAN, V. V., MULLER, F., and HUMMELER, K., J. Immunol. 80, 468

(1958). 5. HALONEN, P., HUEBNER, R. J., and TURNER, H. C., Proc. Sot. Ezptl. Biol.

Med. 97, 530 (1958). 6. MANSON, L. A., ROTHSTEIN, E. L., and RAKE, G. W., Science 126, 546-547

(1957). 7. REYNIERS, J. A., and SACKSTEDER, M. R., Ann. N. Y. Acad. Sci. 78, in

press. 8. TAYLOR, A. R., BRANDON, F. B., and REYNIERS, J. A., Ann. N. Y. Acad. Sci.

78, in press. 9. TAYLOR, A. R., Ann. N. Y. Acad. Sci. 78, in press.

IO. SHARP, D. G., and BEARD, J. W., Ann. N. Y. Acad. Sci. 68, 454-458 (1957). 11. CORIELL, L. L., TALL, M. G., and GASKILL, H., Science 128, 198-199 (1958). 12. BRYAN, W. R., and MOLONEY, J. B., Ann. N. Y. Acad. Sci. 68,441453 (1957).

Research Laboratories Parke, Davis and Company Detroit, Michigan

Received December 8. 1958

A. R. TAYLOR ANNE GILLEN F. B. BRANDON

Measles Immunization with Live Avian Distemper Virus’

Because specific antibodies against canine distemper virus had been shown to be ubiquitous in the serum of human beings (1) and because of a possible relation- ship to common respiratory disease, 200 individuals in a state hospital for the

I Aided by a grant from the Institute of Allergy and Infectious Diseases, Na- tional Institutes of Health, United States Public Health Service.

352 LETTERS TO THE EDITORS

TABLE 1

INCIDENCE OF MEASLES IN THE THREE VACCINATED GROUPS AND

IN UNVACCINATED SUBJECTS

Groups Distemper InfIuenza (controls) Mumps (controls) Unvaccinated subject9

Total in resi- dence (1955)

Number of cases of measles

165 169 160 1190

3 (1.8%) 8 (4.7%) 10 (6.2%) 70 (5.9%)

a Calculated from the total census in November, 1952, which averaged 2000 per day: 600 were eliminated as study subjects, leaving 1400, of which approxi- mately 85yn were in residence at the time of the epidemic, giving a figure of 1190. Attack rate in all control subjects is 5.857,.

mentally retarded were inoculated subcutaneously with 1 ml of live avianized distemper vaccine. Two hundred individuals received influenza vaccine and 200 additional persons were given avianized mumps vaccine.2 The inoculations were carried out in November, 1952.

The presence of distemper antibodies in human sera was confirmed by Imagawa and associates (2) in 1954, by Karzon (S) in 1955, and by Carlstrom (4) in 1956. Subsequently, a pathologic and immunologic relationship between measles (rube- ola) and distemper was demonstrated (5)) and this finding led to a further evalu- ation of the previous immunization study.

The st,ate hospital experienced an epidemic of measles (rubeola) in the latter half of 1955, at which time approximately 10% of the patient population was involved. In the three study groups 15-20°jo of the subjects had left the institution as a result of transfer, discharge, or death, leaving 80-857G in residence at the time of the epidemic. In the accompanying Table 1 the results of this study are recorded.

These results show a three-fold reduction in the attack rate of measles in the subject.s receiving the dist.emper vaccine when compared with t,hree control groups. The significance of this result is not as yet established and would have to be regarded as borderline (P = 0.04). We feel, however, that these findings are worth reporting because of the fact that the first challenge experience of these individuals occurred almost three years following but a single inoculation. The data also support cross-immunity studies from two laboratories previously re- ported (5, 6). The various large control groups, totaling over 1509 subjects (ratio 9 to I), add further support to the unexpected findings.

REFERENCES

f. ADAMS, J. M., Pediatrics 11, 15 (1953). 2. IMAGAWA, D. T., YOSHIMORI, M., WRIGHT, S. W., and ADAMS, J. M., Proc.

Sot. Exptl. Biol. Med. 87, 2 (1954).

2 All vaccines were kindly provided by Dr. H. R. Cox, Lederle Laboratories, Pearl River, New York.

LETTERS TO THE EDITORS 353

3. KARZON, I). T., Pediatrics 16, 809 (1955). 4. CARLSTR~M, G., Acta Paediat. 46, 180 (1956). 6. ADAMS, J. M., and IMAC~AWA, D. T., Proc. Sot. Ezpll. Biol. Med. 96, 210 (1957). 6. CARLSTROM, G., Lancet ii, 344 (1957).

Departments of Pediatrics and Infectious Diseases School of Medicine, University of California Los nngeles, and the

Pacijic State Hospital, Spadra, California Received January 2, 1959

JOHX M. A11.4~ L)~VID T. IMAGAWA

S. W. WRIGHT GEORGE T~RJAN

Deoxyribonucleic Acid Synthesis by Induced Defective and Normal Lysogenic Strains of Escherichia co/i

The rate of replication of phage genetic elements in cultures of the defective lysogenic strain Escherichia coli Cl12 (Xi 1) irradiated with UV light is only 5-16y0 that in cultures of a strain carrying a normal X phage (1). Arber et al. (2) have described a defective lysogenic st,rain, E. coli 3112 (X dy), in which no postindnc- tion replication of phage genetic elements could be demonstrated.

It might be expected that a reduction of the rate of vegetative phage replica- tion in these strains would be reflected in a corresponding reduction of the rate of l>?JA synthesis following induction. Siminovitch (3) has shown t,hat DNB syn- thesis in induced cultures of a defective lysogenic strain of Racillus megatherium is much less than in a normal lysogenic strain. The following experiment,s show that the rate of USA synthesis in induced cultures of E. coli Cl12 (X i 1) and 3112 (X dg) is the same as in the normal lysogenic strain E. coli Cl12 (X s).

Two milliliters of an overnight, culture were diluted with fresh tryptone broth to 400 ml and incubated at 37” with aeration until the viable cell concentration reached 2.5 to 3.5 X 108 cells per milliliter. The entire culture was sediment,ed bg centrifugation, resuspended in 360 ml of warm (37”) buffer and poured onto a large tray (3860 cm*), 75 cm from a 15.watt General Electric germicidal lamp. All cult.ures were irradiated for 50 seconds-a dose of UV light sufficient to kill 40-507, of the cells in a nonlysogenic culture of E. coli Cl12 and to induce phage develop- ment in 9(r997& of the cells in a normal lysogenic culture. After irradiation, the growth medium was reconstituted by addition of 40 ml of a 10% solution of tryp- tone in distilled water. Samples (40 ml) were removed at appropriate time inter- vals and cooled to 6”. DKil was extracted with hot (90”) 5Lj;, trichloroacetic acid (4) and estimated by the diphenylamine reaction (5).

After irradiation of nonlysogenic cultures of E. coli C112, there was a 30.minute lag in DNA synthesis, after which the, DNA concentration increased linearly with time (Fig. 1). The rate of synthesis during the linear portion was 0.05 X 10-e pg per cell per minute. The changes in DNA content of induced cult.ures of E. coli Cl12 (X s) were similar to those in the nonlysogenic cultures (Fig. l), but t~he rate of synt,hesis was twice as great (0.095 X lo-* rg per cell per minute).

The postirradiation changes in DNA concentration for the defective lysogenic strains, E. coli Cl12 (X i 1) and 3112 (X dg) were the same as those in normal lyso- genie cultures (Fig. 1). The rates of DN.4 synthesis after the lag were about the