284 research outputs found
Analyses of hemagglutinin (HA) specific antibody responses using different serological assays after three types of influenza vaccine in children and adults
No full textInfluenza is a contagious respiratory infection caused by a single-stranded, enveloped RNA viruses, able to cause significant morbidity and mortality all over the world, together with a significant economic burden. Vaccination strategies are the most effective methods of preventing and controlling seasonal influenza epidemics that generally occur during winter season. Every year, the composition of the vaccine has to be revaluated due to the antigenic drift mechanism inherent to the influenza viruses. In order to be licensed in the European Union and declared effective and immunogenic, every new influenza vaccine has to fulfill three criteria (at least one of the assessment should meet the requirements) (CPMP/BWP/214/96), for Haemagglutination-inhibition (HI) and/or Single Radial Haemolysis (SRH) assays. Traditionally, influenza vaccines are inactivated preparations administered as a intramuscular injection containing a standardized amount of HA influenza antigen; an alternative way of administration is the intradermal injection, evaluated in the present study. Another type of influenza vaccine, today licensed and available in Russia, U.S.A and in some European countries like Norway, is the live-attenuated influenza vaccine (LAIV), administered as a nasal spray. The actual serological assays, generally used to evaluate the immunogenicity of an influenza vaccine, are the HI and the SRH, for which correlates of protection are established. The Micro-neutralization (MN), although does not present a standardized methodology and approved correlates of protection, is the most sensitive and highest specific assay able to detect functional neutralizing antibody against the HA influenza antigen.
The present work has been divided in three main tasks. The first one is based on the set-up and standardization of a seasonal influenza growth method performed in MDCK-cell culture, with a serum free medium (SF), and a new method for virus titration in MN assay. The second one is a clinical study for the evaluation of the immunogenicity and safety of a quadrivalent intradermal seasonal influenza vaccine conducted in 150 healthy adults. The third one, is a comparative analysis, carried out on a small number of samples, with the aim to assess the difference in the magnitude of HA specific IgG subclass and IgA responses in healthy adults, children (9 years) and health care workers (HCWs) after two different types of seasonal Influenza vaccine: LAIV (Live Cold-Adapted Influenza Vaccine) and IIV (Inactivated Influenza Vaccine). The strain chosen for the purpose of the study is the A/H3N2/Texas/50/2012 seasonal influenza strain (HA1 and HA2).
The intradermal quadrivalent vaccine, results to be comparable, in terms of immunogenicity, to the intramuscular vaccine, confirming the capability of the intradermal injection to elicit a proper immune response. All the CPMP criteria were met for all the four seasonal strains.
Moreover positive correlations were found between the results derived by the three different serological assays able to detect different anti HA-influenza antibodies in serum samples.
The LAIV vaccine was to be able to promote a stronger systemic immune response in children than in adults. In adults, TIV induces better antibody responses compared to LAIV, but comparable antibody response to that induced in LAIV vaccinated children. The different mechanism of action of LAIV versus TIV, may explain the relative efficacy between the two vaccines in children and adults. In children, the avidity of pre-existing serum antibodies plays a role in determining the antibody response to infection. The present results suggest that exposure history and the type of vaccine play a significant role in determining the antibody response
Centrifugal Decantation
No full textTwo liquid phases can be separated by decantation taking advantage of their different densities. When residence time should be lowered down centrifugal force instead of gravitational one can be employed. The centrifugal decanter design is based on a pressure balance and the outlet can be properly located in order to allow for a continuous operation
Lyophilization
No full textDue to the thermolability of food and pharmaceutical products the drying process cannot be performed at high temperature; lyophilization replaces then standard drying units taking advantage of sublimation instead of evaporation. Being freeze drying a batch operation, a suitable model is used to assess the operating residence time for given operating conditions. The critical importance of an optimal control system for the productivity maximization will be discussed by mean of an common industrial case study
Crystallization
No full textCrystallization is the non-conventional operation allowing to obtain crystals with high purity from a liquor. Taking advantage of different components solubilities, more than one pure species can be obtained from the same solution. Nucleation and growth phases can be described by dedicated models. The delta-L law derivation for the crystal growth process is explained in detail and the relationship between linear growth and growth ratio is discussed by mean of a case study
Spray Drying
No full textWhen suspensions, aerosols or slurries contain solid particles that cannot be mechanically dried a spray dryer should be employed. Widely spread in food and pharma industry, spray dryers are suitable to ensure low residence time at high temperature. The unit height is designed according to the residual moisture specification by mean of an ODEs system arising from mass and heat balances
Drying
No full textDrying is the most general expression for a set of operations aimed to remove the moisture contained in solid matrix products by mean of heat transfer. Due to the several possible configurations a wide range of models exists; they share in common heat and mass balances both in case of direct and indirect heat transfer. Internal diffusion can be either taken into account or neglected and a proper discretization should be used to model this phenomenon
Heat Pumps
No full textHeat pumps are widespread units employed in the daily life whether a consistent amount of energy is available at a low enthalpic level (i.e. not suitable temperature). Their particular efficiency is shown by mean of a practical example where heat balances and operating conditions are thoroughly discussed. The sizing of each unit (evaporator, condenser and compressor) follows the process design in order to provide a complete overview
Pinch Technology
No full textPinch technology is the best practice for heat exchanger networks optimization from an OPerating EXpenses point of view. Its main goal is to find a compromise between the investment required for the additional units and the external duty demand. The standard procedure is based on a preliminary thermodynamic assessment followed by the network optimization according to the feasibility of the operation. The results thus obtained allow then the decision maker to select the optimal solution according the specific needs of the case under analysis
Centrifugal Sedimentation
No full textSedimentation is a separation technology alternative to filtration for liquid-solid separation. By taking advantage of different inertial behavior the centrifugal field allows for the solid deposition on the sedimenter wall and for a continuous clarified liquid removal. A multi-layered configuration, within the feasibility limits, enhances the separation effectiveness as shown in the design problem
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