Mechanism of the effect of 2, 2 '-azobis (2-amidinopropane) dihydrochloride simulated lipid oxidation on the IgG/IgE binding ability of ovalbumin
FOOD CHEMISTRY
Authors: Zhang, Jing-jing; Tu, Zong-cai; Wang, Hui; Hu, Yue-ming; Du, Peng-cheng; Yang, Yi-peng
Abstract
In this work, the mechanism of the effect of lipid oxidation on the IgG/IgE binding ability of ovalbumin (OVA) was investigated via the peroxyl radicals produced by 2, 2'-azobis (2-amidinopropane) dihydrochloride to simulate lipid oxidation. Results showed that the structure of OVA unfolded partially with an increase in oxidation degree, leading to the exposure of the allergenic epitopes and increasing the IgG/IgE binding ability of OVA. Nine oxidation sites were found on the a-helix, and these sites may unwind the a-helix and expose the allergenic epitopes on the OVA surface, leading to antibody recognition and combination. Consequently, the IgG/IgE binding ability of OVA was increased. In conclusion, the allergenic capacity of OVA can be promoted by modifying peroxyl radical oxidation in processing egg products.
Comparative Evaluation of Prophylactic SIV Vaccination Modalities Administered to the Oral Cavity
AIDS RESEARCH AND HUMAN RETROVIRUSES
Authors: Chaudhary, Omkar; Wang, Lingyun; Bose, Deepanwita; Narayan, Vivek; Yeh, Ming Te; Carville, Angela; Clements, John D.; Andino, Raul; Kozlowski, Pamela A.; Aldovini, Anna
Abstract
Attempts to develop a protective human immunodeficiency virus (HIV) vaccine have had limited success, especially in terms of inducing protective antibodies capable of neutralizing different viral strains. As HIV transmission occurs mainly via mucosal surfaces, HIV replicates significantly in the gastrointestinal tract, and the oral route of vaccination is a very convenient one to implement worldwide, we explored three SIV vaccine modalities administered orally and composed of simian immunodeficiency virus (SIV) DNA priming with different boosting immunogens, with the goal of evaluating whether they could provide lasting humoral and cellular responses, including at mucosal surfaces that are sites of HIV entry. Twenty-four Cynomolgus macaques (CyM) were primed with replication-incompetent SIV DNA provirus and divided into three groups for the following booster vaccinations, all administered in the oral cavity: Group 1 with recombinant SIV gp140 and Escherichia coli heat-labile toxin adjuvant dmLT, Group 2 with recombinant SIV-Oral Poliovirus (SIV-OPV), and Group 3 with recombinant SIV-modified vaccinia ankara (SIV-MVA). Cell-mediated responses were measured using blood, lymph node, rectal and vaginal mononuclear cells. Significant levels of systemic and mucosal T-cell responses against Gag and Env were observed in all groups. Some SIV-specific plasma IgG, rectal and salivary IgA antibodies were generated, mainly in animals that received SIV DNA + SIV-MVA, but no vaginal IgA was detected. Susceptibility to infection after SIVmac251 challenge was similar in vaccinated and nonvaccinated animals, but acute infection viremia levels were lower in the group that received SIV DNA + SIV-MVA. Nonvaccinated CyM maintained central memory and total CD4(+) T-cell levels in the normal range during the 5 months of postinfection follow-up as did the vaccinated animals, precluding evaluation of vaccine impact on disease progression. We conclude that the oral cavity vaccination tested in these regimens can stimulate cell-mediated immunity systemically and mucosally, but humoral response stimulation was limited with the doses and the vaccine platforms used.