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Differences among primates in defence against infection: sensitivity of polymorphonuclear leukocytes to fMet-Leu-Phe
Abstract:
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.
Insights
Primate polymorphonuclear leukocytes (PMN) show increasing sensitivity to N-formyl-methionyl-leucyl-phenylalanine (fMet-Leu-Phe) with evolutionary proximity to humans, suggesting enhanced immune defense in higher primates.
Area of Science:
- Immunology
- Evolutionary Biology
- Cell Biology
Background:
- Polymorphonuclear leukocytes (PMN) are crucial immune cells involved in host defense against pathogens.
- N-formyl-methionyl-leucyl-phenylalanine (fMet-Leu-Phe) is a potent chemoattractant and activator of PMNs.
- Comparative studies of immune responses across species can elucidate evolutionary trends in defense mechanisms.
Purpose of the Study:
- To investigate the sensitivity of PMN from different primate species to fMet-Leu-Phe.
- To compare the chemotaxis and lysosomal enzyme release responses of human, chimpanzee, rhesus monkey, and tamarin PMNs to fMet-Leu-Phe.
- To explore the evolutionary correlation between primate phylogeny and PMN sensitivity to immune stimuli.
Main Methods:
- PMN were isolated from four primate species: human (H. sapiens), chimpanzee (P. troglodytes), rhesus monkey (M. mulatta), and cotton-headed tamarin (S. (O) oedipus).
- The 50% effective concentrations (EC50) of fMet-Leu-Phe were determined for PMN chemotaxis and for the release of myeloperoxidase (MPO) and beta-glucuronidase.
- Statistical analysis was performed to compare EC50 values across species.
Main Results:
- PMN sensitivity to fMet-Leu-Phe for chemotaxis followed the order: chimpanzee ≈ human > rhesus monkey > tamarin.
- Sensitivity for lysosomal enzyme release (MPO and beta-glucuronidase) followed the order: human > chimpanzee > rhesus monkey > tamarin.
- Lower EC50 values indicated higher sensitivity, with tamarins exhibiting the lowest sensitivity and humans/chimpanzees the highest.
Conclusions:
- PMN sensitivity to fMet-Leu-Phe increases with the evolutionary progression towards humans.
- This heightened sensitivity in higher primates may correlate with enhanced immune defense functions against infections.
- The study highlights conserved yet evolving immune pathways across primate evolution.