Temperature Pretreatment Alters the Polarization Response of Human Neutrophils to the Chemoattractant N-formyl-Met-Leu-Phe

Neutrophils present a polarized morphology upon stimulation of chemoattractants, which play a vital role in host-defense mechanisms. Many studies have been published on neutrophil polarization, in which three different temperatures pretreatment (4°C, 25°C and 37°C) have been used. However, no study has investigated whether different temperature pretreatments affect neutrophil polarization. In the current study, we examined the effects of 4°C, 25°C and 37°C pretreatment temperatures on short-term (1 or 3 min) chemoattractant-induced polarization. Human neutrophils were polarized upon the stimulation of N-formyl-Met-Leu-Phe (fMLP) after pretreated by different temperature. The morphological changes of the neutrophils were investigated under the microscopy. The F-actin polymerization was determined by immunological histological chemistry. There were more head–tail polarized cells (>50% of the cells) in the 25°C and 37°C pretreatment groups than in the 4°C group (32.4%). The average lengths of the pseudopod were 3.2 ± 1.1 μm (n = 17), 5.3 ± 2.1 μm (n = 12) and 7.4 ± 2.7 μm (n = 21) in the 4°C, 25°C and 37°C pretreatment groups, respectively; the 4°C and 37°C pretreatment groups were statistically different (P < 0.05). Additionally, there was a statistically significant difference in the pseudopod extension rate among the three groups, as well as the Lamellipod percentage between the 4°C group and the other two groups within 1 min of stimulation with fMLP. This study demonstrates that different temperature pretreatments affect neutrophil polarization upon short-term stimulation with fMLP.