Human polymorphonuclear leukocytes respond to waves of chemoattractant, like Dictyostelium

Area of Science:

• Cellular Biology
• Immunology
• Biophysics

Background:

• The established model for immune cell attraction to infection sites involves a standing spatial gradient of chemoattractants.
• This model's stability over long distances and durations is questionable.
• The natural chemotactic signal in Dictyostelium discoideum is an outwardly relayed, non-dissipating wave.

Purpose of the Study:

• To investigate the hypothesis that human polymorphonuclear leukocytes (PMNs) respond to chemoattractant waves, similar to Dictyostelium discoideum.
• To challenge the traditional view of chemoattractant gradients as the sole long-distance signaling mechanism for PMNs.

Main Methods:

• PMNs were exposed to a chemoattractant wave signal modeled after the Dictyostelium discoideum aggregation wave.
• PMN behavioral responses were analyzed across all four phases of the artificial chemoattractant wave.

Main Results:

• PMNs exhibited distinct behavioral alterations in response to each of the four phases of the chemoattractant wave.
• The observed PMN responses mirrored those of Dictyostelium discoideum when exposed to similar wave stimuli.
• These findings indicate that PMNs possess the necessary cellular machinery to interpret and react to chemoattractant wave signals.

Conclusions:

• PMNs are capable of responding to chemoattractant waves, suggesting this mechanism is biologically relevant.
• The results support the hypothesis that chemoattractant waves, rather than solely gradients, may guide PMNs to infection sites in humans over long distances.
• This challenges the conventional understanding of leukocyte chemotaxis and proposes a novel signaling paradigm for immune response.