HBD-2 interactions with erythrocyte membranes In Vitro

Abstract

HBD-2 – a member of β-defensin family of antimicrobial peptides – is known to permeabilize cell membranes of susceptible cells, but the mechanism of such interactions is poorly understood. In our study, we used a hemolytic model to explore the kinetic properties of HBD-2 interactions with membranes of human erythrocytes. We ran hemolytic assays with a wide range of both HBD-2 and erythrocyte concentrations, as well as varying pH values, incubation times, and osmotic strengths; each in the presence or the absence of inhibitory substances such as proteins and salts. The results show that HBD-2 cell membrane permeabilization is both dose- and time-dependent (with plateau effect observed in each case), and inversely dependent on erythrocyte concentration. HBD-2 interactions with cell membranes highly depend on pH value and the presence of inhibitors but are not affected by tested osmotic strength range. Our findings suggest that interactions of HBD-2 with cell membranes are mainly electrostatic in nature and are limited by released cell content. We developed a speculative model of such interaction based on our results.