PERIPHERAL-BLOOD GRANULOCYTES AND MONONUCLEAR CELL RESPONSES IN MONKEYS WITH EXPERIMENTAL SHIGELLOSIS

Changes in neutrophil response to N-formyl-methionyl-leucyl-phenylalan ine (FMLP) and the phenotype of peripheral blood mononuclear cells wer e studied in monkeys after oral challenge with Shigellae. Monkeys were first challenged with S. dysenteriae 1 which caused shigellosis in so me of the monkeys. After recovery, the monkeys were rechallenged with S. flexneri 2a. No difference in sensitivity was observed in the monke ys during shigellosis caused by either S. dysenteriae 1 or S. flexneri 2a. The optimal dose of FMLP for neutrophil polarization, a measure o f early cell activation, in normal healthy monkeys was 10(-7) M when 6 7% of the neutrophils were polarized. Neutrophils from monkeys ill wit h shigellosis required higher doses of FMLP (10(-6) and 5 X 10(-7) M) for maximum polarization. As the monkeys recovered, a gradual decrease in the doses of FMLP for optimal neutrophil polarization was also obs erved. The percentage of CD2-positive T lymphocytes, the earliest mark er for T lymphocytes in the peripheral blood, decreased when the monke ys developed shigellosis and returned to normal levels as the monkeys improved. However, there was no change in the percentage of CD20-posit ive peripheral blood B lymphocytes.