Separation of Lysozyme-Ovotransferrin Complexes and the Cooperative Role of Their Components in Egg White.

A complex of ovotransferrin and lysozyme was directly isolated from egg white using an anti-transferrin antibody-immobilized membrane after antiserum proteins were separated by non-denaturing two-dimensional electrophoresis and transferred onto a membrane. The complex retained lysozyme activity that catalyzes the breakdown of peptidoglycans in the bacterial cell wall at the ß1-4 bond between N-acetylmuramic acid and N-acetylglucosamine residues. The activity of the purified lysozyme was suppressed to 6.4% in the presence of 1 µmol Fe2+, whereas that of the mixture of the purified lysozyme and ovotransferrin was maintained at 58%. The activity of the purified lysozyme was suppressed to 35% in the presence of 10 nmol Fe3+, whereas that of the mixture of the purified lysozyme and ovotransferrin was maintained at 66%. Furthermore, the bacteriolytic activity against Bacillus subtilis of egg white with reduced glycoproteins such as ovotransferrin was assessed, and the bacteriolytic activity was found to be suppressed in the presence of Fe2+ and Fe3+. This suppression was ions, thereby alleviating the inhibition of lysozyme activity by iron ions. A complex of ovotransferrin and lysozyme is efficient because ovotransferrin effectively captures iron ions near lysozyme. Thus, protein complexes containing enzymes can be applied to control their activity.

A phase 3 randomized study to evaluate safety and immunogenicity of 20-valent pneumococcal conjugate vaccine in healthy Japanese infants.

OBJECTIVES: Safety and immunogenicity evaluation of a 4-dose series with 20-valent pneumococcal conjugate vaccine (PCV20). METHODS: This phase 3, double-blind study randomized healthy Japanese infants to receive 4 doses (3 infant doses, 1 toddler dose) of PCV20 by subcutaneous (SC) or intramuscular (IM) injection or 13-valent PCV (PCV13) SC. A primary immunogenicity objective was to demonstrate noninferiority of PCV20 SC to PCV13 SC for percentages of participants meeting predefined serotype-specific immunoglobulin G concentrations 1 month after Dose 3. The 7 additional PCV20 serotypes were compared with the lowest vaccine serotype result in the PCV13 group. Safety and tolerability were assessed as the primary safety objective. RESULTS: Overall, 668 participants were randomized (PCV20 SC, n = 226; PCV13 SC, n = 224; PCV20 IM, n = 218). The primary noninferiority objective for PCV20 SC to PCV13 SC was met for 11/13 matched and 5/7 additional serotypes. Additional data showed PCV20 SC and IM elicited robust functional opsonophagocytic activity and boosting responses to all 20 vaccine serotypes. PCV20 had a similar safety/tolerability profile to PCV13, although local reactions were less frequent with PCV20 IM. CONCLUSIONS: A 4-dose series of PCV20 SC or IM elicited immune responses expected to be protective against all 20 serotypes in Japanese infants. NCT04530838.