Monitoring human parvovirus B19 virus-like particles and antibody complexes in solution by fluorescence correlation spectroscopy

Abstract

Fluorescence correlation spectroscopy (FCS) was used in monitoring human parvovirus B19 virus-like particle (VLP) antibody complexes from acute phase and past-immunity serum samples. The Oregon Green 488-labeled VLPs gave an average diffusion coefficient of 1.7 x 10(-7) cm2 s(-1) with an apparent hydrodynamic radius of 14 nm. After incubation of the fluorescent VLPs with an acute phase serum sample, the mobility information obtained from the fluorescence intensity fluctuation by autocorrelation analysis showed an average diffusion coefficient of 1.5 x 10(-8) cm2 s(-1), corresponding to an average radius of 157 nm. In contrast, incubation of the fluorescent VLPs with a past-immunity serum sample gave an average diffusion coefficient of 3.5 x 10(-8) cm2 s(-1) and a radius of 69 nm. A control serum devoid of B19 antibodies caused a change in the diffusion coefficient from 1.7 x 10(-7) to 1.6 x 10(-7) cm2 s(-1), which is much smaller than that observed with acute phase or past-immunity sera. Thus, VLP-antibody complexes with different diffusion coefficients could be identified for the acute phase and past-immunity sera. FCS measurement of VLP-immune complexes could be useful in distinguishing between antibodies present in acute phase or past-immunity sera as well as in titration of the VLPs.

Expression and subcellular targeting of canine parvovirus capsid proteins in baculovirus‐transduced NLFK cells

“…The BEVS has been used to produce a variety of parvovirusspecific proteins. Among these, virus-like particles (VLPs) have been produced for adeno-associated virus [25], Aleutian mink disease parvovirus [26], muscovy duck parvovirus [27], human parvovirus B19, porcine parvovirus [28][29][30], and canine parvovirus [31][32][33][34][35]. Recently, baculoviral vectors have also been used to efficiently mediate gene transfer and expression in various mammalian cell lines both in vitro [36][37][38][39][40][41][42][43][44][45] and in vivo [46][47][48][49].…”

Novel spiking methods developed for anion exchange chromatography operating in a continuous process

“…The time scale for diffusion can be estimated using the following equation: where L is the diffusion distance and D 0 is the diffusion coefficient (Bird, Stewart, & Lightfoot, 2007). The diffusion coefficient for MMV can be estimated as 1.6 × 10 −7 cm 2 /s, using the diffusion coefficient found for human parvovirus B19 particles, due to similarity in their sizes and shapes (Toivola et al, 2004). The extra‐particle flow channel is estimated to be about one‐third of the resin bead size (Du Plessis & Woudberg, 2008; Ingham & Pop, 1998), which is close to 30 µm for Eshmuno resins.…”

“…where L is the diffusion distance and D 0 is the diffusion coefficient (Bird, Stewart, & Lightfoot, 2007). The diffusion coefficient for MMV can be estimated as 1.6 × 10 −7 cm 2 /s, using the diffusion coefficient found for human parvovirus B19 particles, due to similarity in their sizes and shapes (Toivola et al, 2004). The extra-particle flow T A B L E 3 Impurity removal by Eshmuno Q anion exchange chromatography using different loading and spiking methods Note: Experiments were performed in product flow-through mode in Tris-HCl buffer (pH 8.5 and conductivity 6 mS/cm); residence time was maintained at 4 min for all runs.…”