Differences among primates in defence against infection: sensitivity of polymorphonuclear leukocytes to fMet-Leu-Phe.

The sensitivity of polymorphonuclear leukocytes (PMN) to N-formyl-methionyl-leucyl-phenylalanine (fMet-Leu-Phe) for chemotaxis and for lysosomal enzyme release was examined using the PMN of four primate species, human (H. sapiens), chimpanzee (P. troglodytes), rhesus monkey (M. mulatta), and cotton-headed tamarin (S. (O) oedipus). The 50 per cent effective concentrations (EC50) of fMet-Leu-Phe for chemotaxis were 2.5 X 10(-9) M in human, 10(-9) M in chimpanzee, 8 X 10(-8) M in rhesus monkey, and 3.3 X 10(-6) M in tamarin. The EC50 values of fMet-Leu-Phe for myeloperoxidase (MPO) release were 10(-8) M in human, 4 X 10(-8) M in chimpanzee, 4 X 10(-8) M in rhesus monkey, and 10(-6) M in tamarin and those for beta-glucuronidase release were 4 X 10(-9) M, 6.4 X 10(-8) M, 1.8 X 10(-7) M, and 1.6 X 10(-6) M, respectively. Thus, the sensitivity to fMet-Leu-Phe for chemotaxis was in the order: chimpanzee congruent to human greater than rhesus monkey greater than tamarin, and that for the release of lysosomal enzymes, MPO and beta-glucuronidase, was in the order: human greater than chimpanzee greater than rhesus monkey greater than tamarin. These results appear to indicate that the sensitivity to fMet-Leu-Phe increases in the order of evolution of primates toward the human, and suggest that the sensitivity of PMN in the defence function against infection also increases in the same order.