AFM force measurements of the gp120–sCD4 and gp120 or CD4 antigen–antibody interactions

Abstract

Soluble CD4 (sCD4), anti-CD4 antibody, and anti-gp120 antibody have long been regarded as entry inhibitors in human immunodeficiency virus (HIV) therapy. However, the interactions between these HIV entry inhibitors and corresponding target molecules are still poorly understood. In this study, atomic force microscopy (AFM) was utilized to investigate the interaction forces among them. We found that the unbinding forces of sCD4-gp120 interaction, CD4 antigen-antibody interaction, and gp120 antigen-antibody interaction were 25.45 ± 20.46 pN, 51.22 ± 34.64 pN, and 89.87 ± 44.63 pN, respectively, which may provide important mechanical information for understanding the effects of viral entry inhibitors on HIV infection. Moreover, we found that the functionalization of an interaction pair on AFM tip or substrate significantly influenced the results, implying that we must perform AFM force measurement and analyze the data with more caution.

Effects of long-term serial cell passaging on cell spreading, migration, and cell-surface ultrastructures of cultured vascular endothelial cells

“…3b). Next, we made use of our expertise of atomic force microscopy (AFM) (Chen 2012;Chen et al 2011;Jin et al 2011;Jin et al 2012) to investigate the effects of cell passaging on cell-surface ultrastructures of HUVECs. Generally, there exist three regions with different degrees of roughness in the plasma membrane of a HUVEC cell ): region 1 above the nucleus, region 2 surrounding the nucleus, and region 3 near cell boundary (Fig.…”

Detection of human erythrocytes influenced by iron deficiency anemia and thalassemia using atomic force microscopy

“…AFM has been used by several research groups to investigate chromosomes (Hoshi and Ushiki, 2011), cell membranes (Suresh and Edwardson, 2010), proteins (Engel, 2011), DNA (Di Bucchianico et al, 2011), RNA structure (Heus et al, 2011), nucleic acid-protein complexes (Miklaszewska et al, 2004), ligand-receptor binding (Odorico et al, 2007), carbohydrates (Lesoil et al, 2010), lipids, living cells. The unique combination of high-resolution imaging and functionality in a physiological environment has made AFM useful for investigating living cells, including yeasts (Moreno-Herrero et al, 2001), bacteria (Lower, 2011), virally infected cells (Chen et al, 2011), and neurons (Ricci et al, 2011). There have been only a few published reports associated with the use of AFM to observe erythrocytes (Maciaszek and Lykotrafitis, 2011;O'Reilly et al, 2001;el-Shoura, 1993) and none of these studies focused on the morphological properties of different types of anemia.…”

An atomic-force basis for the bacteriolytic effects of granulysin

“…It is also worth to note that such interaction force (i.e. 22.5 pN) between GNL and L. monocytogenes is comparable to other interactions in biological systems which has very strong binding ability such as CD4 antigen and anti-CD4 antibody interaction that is about 25.45 pN [35]. While granulysin is regarded as an effective antimicrobial molecules secreted by some active immune cells such as CD8 + and CD4 + T cells [14,36,37], such strong interaction force between granulysin and bacteria implicates a previously unknown biomechanical mechanism underlying the bacteriolytic effects of granulysin.…”