Toolbox for Non-Intrusive Structural and Functional Analysis of Recombinant VLP Based Vaccines: A Case Study with Hepatitis B Vaccine

Background: Fundamental to vaccine development, manufacturing consistency, and product stability is an understanding of the vaccine structure-activity relationship. With the virus-like particle (VLP) approach for recombinant vaccines gaining popularity, there is growing demand for tools that define their key characteristics. We assessed a suite of non-intrusive VLP epitope structure and function characterization tools by application to the Hepatitis B surface antigen (rHBsAg) VLP-based vaccine. Methodology: The epitope-specific immune reactivity of rHBsAg epitopes to a given monoclonal antibody was monitored by surface plasmon resonance (SPR) and quantitatively analyzed on rHBsAg VLPs in-solution or bound to adjuvant with a competitive enzyme-linked immunosorbent assay (ELISA). The structure of recombinant rHBsAg particles was examined by cryo transmission electron microscopy (cryoTEM) and in-solution atomic force microscopy (AFM). Principal Findings: SPR and competitive ELISA determined relative antigenicity in solution, in real time, with rapid turnaround, and without the need of dissolving the particulate aluminum based adjuvant. These methods demonstrated the nature of the clinically relevant epitopes of HBsAg as being responsive to heat and/or redox treatment. In-solution AFM and cryoTEM determined vaccine particle size distribution, shape, and morphology. Redox-treated rHBsAg enabled 3D reconstruction from CryoTEM images – confirming the previously proposed octahedral structure and the established lipidto-protei

Growth and tolerance of infants fed formula supplemented with polydextrose (PDX) and/or galactooligosaccharides (GOS): double-blind, randomized, controlled trial

<p>Abstract</p> <p>Background</p> <p>To ensure the suitability of an infant formula as the sole source of nutrition or provide benefits similar to outcomes in breastfed infants, advancements in formula composition are warranted as more research detailing the nutrient composition of human milk becomes available. This study was designed to evaluate growth and tolerance in healthy infants who received one of two investigational cow’s milk-based formulas with adjustments in carbohydrate, fat, and calcium content and supplemented with a prebiotic blend of polydextrose (PDX) and galactooligosaccharides (GOS) or GOS alone.</p> <p>Methods</p> <p>In this multi-center, double-blind, parallel-designed, gender-stratified prospective study 419 infants were randomized and consumed either a marketed routine cow’s milk-based infant formula (Control; Enfamil® LIPIL®, Mead Johnson Nutrition, Evansville, IN) (n = 142) or one of two investigational formulas from 14 to 120 days of age. Investigational formulas were supplemented with 4 g/L (1:1 ratio) of a prebiotic blend of PDX and GOS (PDX/GOS; n = 139) or 4 g/L of GOS alone (GOS; n = 138). Anthropometric measurements were taken at 14, 30, 60, 90, and 120 days of age. Daily recall of formula intake, tolerance, and stool characteristics was collected during study weeks 1 and 2 and 24-h recall was collected at 60, 90, and 120 days of age. Medically-confirmed adverse events were recorded throughout the study.</p> <p>Results</p> <p>There were no group differences in growth rate from 14 to 120 days of age. Discontinuation rates were not significantly different among study groups. No differences in formula intake or infant fussiness or gassiness were observed. During study weeks 1 and 2 and at 60 days of age stool consistency ratings were higher (i.e. softer stools) for infants in the PDX/GOS and GOS groups versus Control and remained higher at 120 days for the PDX/GOS group (all <it>P</it> < 0.05). The overall incidence of medically-confirmed adverse events was similar among groups.</p> <p>Conclusions</p> <p>Investigational routine infant formulas supplemented with 4 g/L of either a prebiotic blend of PDX and GOS or GOS alone were well-tolerated and supported normal growth. Compared to infants who received the unsupplemented control formula, infants who received prebiotic supplementation experienced a softer stooling pattern similar to that reported in breastfed infants.</p> <p>Trial registration</p> <p>ClinicalTrials.gov Identifier: NCT00712608</p