Seasonal influenza vaccines and hurdles to mutual protection

One HA stalk topping multiple heads as a novel influenza vaccine

Classic chimeric hemagglutinin (cHA) was designed to induce immune responses against the conserved stalk domain of HA. However, it is unclear whether combining more than one HA head domain onto one stalk domain is immunogenic and further induce immune responses against influenza viruses. Here, we constructed numerous novel cHAs comprising two or three fuzed head domains from different subtypes grafted onto one stalk domain, designated as cH1-H3, cH1-H7, cH1-H3-H7, and cH1-H7-H3. The three-dimensional structures of these novel cHAs were modelled using bioinformatics simulations. Structural analysis showed that the intact neutralizing epitopes were exposed in cH1-H7 and were predicted to be immunogenic. The immunogenicity of the cHAs constructs was evaluated in mice using a chimpanzee adenoviral vector (AdC68) vaccine platform. The results demonstrated that cH1-H7 expressed by AdC68 (AdC68-cH1-H7) induced the production of high levels of binding antibodies, neutralizing antibodies, and hemagglutinin inhibition antibodies against homologous pandemic H1N1, drifted seasonal H1N1, and H7N9 virus. Moreover, vaccinated mice were fully protected from a lethal challenge with the aforementioned influenza viruses. Hence, cH1-H7 cHAs with potent immunogenicity might be a potential novel vaccine to provide protection against different subtypes of influenza virus.

Older adults: panoramic view on the COVID-19 vaccination

In December 2020, COVID-19 vaccination started in many countries, with which the world community hopes to stop the further spread of the current pandemic. More than 90% of sick and deceased patients belong to the category of older adults (65 years and older). This category of the population is most vulnerable to infectious diseases, so vaccination is the most effective preventive strategy, the need for which for older adults is indisputable. Here we briefly summarize information about age-related changes in the immune system and present current data on their impact on the formation of the immune response to vaccination. Older age is accompanied by the process of biological aging accompanied by involution of the immune system with increased susceptibility to infections and a decrease in the effect of immunization. Therefore, in the ongoing mass COVID-19 vaccination, the older adults are a growing public health concern. The authors provide an overview of the various types of COVID-19 vaccines approved for mass immunization of the population by the end of 2020, including older adults, as well as an overview of strategies and platforms to improve the effectiveness of vaccination of this population. In the final part, the authors propose for discussion a system for assessing the safety and monitoring the effectiveness of COVID-19 vaccines for the older adults.

Evolution of Therapeutic Antibodies, Influenza Virus Biology, Influenza, and Influenza Immunotherapy

This narrative review article summarizes past and current technologies for generating antibodies for passive immunization/immunotherapy. Contemporary DNA and protein technologies have facilitated the development of engineered therapeutic monoclonal antibodies in a variety of formats according to the required effector functions. Chimeric, humanized, and human monoclonal antibodies to antigenic/epitopic myriads with less immunogenicity than animal-derived antibodies in human recipients can be produced in vitro. Immunotherapy with ready-to-use antibodies has gained wide acceptance as a powerful treatment against both infectious and noninfectious diseases. Influenza, a highly contagious disease, precipitates annual epidemics and occasional pandemics, resulting in high health and economic burden worldwide. Currently available drugs are becoming less and less effective against this rapidly mutating virus. Alternative treatment strategies are needed, particularly for individuals at high risk for severe morbidity. In a setting where vaccines are not yet protective or available, human antibodies that are broadly effective against various influenza subtypes could be highly efficacious in lowering morbidity and mortality and controlling unprecedented epidemic/pandemic. Prototypes of human single-chain antibodies to several conserved proteins of influenza virus with no Fc portion (hence, no ADE effect in recipients) are available. These antibodies have high potential as a novel, safe, and effective anti-influenza agent.