Effect of Hyperleukocytosis (Hyperleukocytic Pre-Immunity) on Infection. ∗

Abstract

In the previous article 1 it was demonstrated that a single intraperitoneal injection of heat killed B. coli may prevent the death of a dog from an otherwise lethal B. coli peritoneal infection. The peritonitis was produced the day after the protecting injection. Four successive injections on successive days resulted in the survival of 65% of the animals. No humoral antibodies were found to account for this protection. In order to determine the role played by the cellular antibodies, cell counts of the peripheral blood and of the peritoneal exudate and peritoneal bacterial counts were made hourly during the course of a peritoneal infection in normal and protected dogs. Throughout these experiments, peritonitis was produced by the intraperitoneal introduction of 3 billion living B. coli suspended in 40 cc. of a 2 1/2% gum tragacanth.

The peripheral leukocytes of normal dogs dropped rapidly and seldom exceeded the count prior to onset of infection. The leukocytes in the peritoneal exudate were polymorphonuclears and were seldom more than 50,000 per cu. mm. The bacteria in the peritoneal exudate were always present in large numbers both free and phagocytosed.

The protected dogs that survived had consistently higher peripheral blood leukocyte counts than the normal animals and the leukocytes rapidly exceeded the count prior to infection. The leukocytes of the peritoneal exudate prior to onset of infection were present in large numbers (232,000 to 546,000 per cu. mm.) and were predominantly polymorphonuclears. After the onset of peritonitis, the number of peritoneal leukocytes dropped considerably and consistently while the total leukocyte counts were higher than in the normal dogs. The bacteria in the peritoneal exudate disappeared rapidly so that in 4 to 5 hours the counts were in thousands instead of many millions as in the normal dogs.