David M. Donaldson

Serum β-Lysin and Muramidase Levels in Germfree and Conventional Rats

Summary A comparative study of serum β-lysin and muramidase activity in germfree, ex-germfree and conventional rats showed no significant differences in β-lysin levels between the three groups; however, upon separation and purification of β-lysin from germfree serum, unusual differences in the bactericidal activity of the different fractions obtained were noted. The CV rats showed significantly higher levels of muramidase than exGF or GF rats and these differences were closely correlated with differences in blood granulocyte counts. Higher levels of both β-lysin and muramidase were found in exGF male rats in contrast to exGF females. We thank Dr. David W. Ailing, NIAID, NIH, for the statistical analyses and Drs. John E. Tobie and Phillip J. Baker for their criticisms of this manuscript.

Suppression of Normal Bactericidal Action of Rabbit Serum Following Whole Body X-Irradiation.

Summary 1. Whole body x-irradiation of 650 to 725r results in depression of the normal bactericidal activity of rabbit serum. 2. With the x-irradiation doses employed, the bactericidal action of serum from rabbits is normal on the first post-irradiation day, is depressed by the fifth day following whole body x-irradiation and returns in surviving animals by the twentieth post-irradiation day. 3. Following a second dose of 650r, serum bactericidal activity is depressed earlier and remains depressed for a longer time than after the first 650r x-irradiation exposure.