Serological Aspects of the Suppression of Normal Bactericidal Action of Rabbit Serum Following Whole Body X-Irradiation

Abstract

The loss or suppression of the normal bactericidal activity of rabbit serum following 650 to 725 r of whole body x-irradiation was not demonstrated to be due to a substance in the sera of irradiated rabbits which inhibits normal bactericidal activity. No decrease in the bactericidal action of normal serum was observed following the addition of serum from x-irradiated rabbits to normal serum. Titrations were carried out with sera from nonimmunized x-irradiated and control rabbits to determine natural agglutinin levels. Suspensions of sheep red blood cells and Bacillus subtilis were employed as antigens. The amount of circulating natural agglutinin was not significantly altered in the sera of x-irradiated rabbits with suppressed bactericidal activity. Complement concentrations determined at a time when the sera from irradiated rabbits showed suppressed bactericidal activity were of the same magnitude in x-irradiated and control rabbits. Addition of either E or M fractions of guinea pig complement failed to restore the bactericidal activity of sera from x-irradiated rabbits.