Background: In the last decade, adjuvant-containing vaccines, exerting different effects on the immune system, including the production of cytokines, which are one of the most important regulatory systems of the body, are introduced into practice. Objectives: An effect of the immunoadjuvant polymer-subunit and adjuvant-free vaccines against influenza on the cytokine profile of mononuclear leukocytes in 27 healthy women was studied. Methods: The study of cytokine profile in human peripheral blood mononuclear leukocytes exposed to vaccines against influenza virus was determined by flow cytometry method (Cytomix FC-500, Beckman Coulter, USA) using the Multiplex-13 test system (Bender MedSystems, Austria). Results: It was established that all the studied vaccines leaded to somewhat increased levels of Th1/Th2/Th17/Th9/Th22 cytokines in the culture fluid of peripheral blood mononuclear leukocytes (PBML), which indicates the activation of both humoral and cellular immunity. An immunoadjuvant vaccine has been shown to be superior in activating the synthesis of Th1 (IL-12, INF-g, IL-2, IL-6, IL-1β, TNF-α) cytokines, IL-9 and IL-22, while the subunit vaccine was superior in activating the synthesis of IL-4, and split vaccine—of IL-5. Conclusions: Immunoadjuvant vaccine is superior in terms of inducing cellular immune effectors to a greater extent compared to subunit and split vaccines.

To date, the advantage of adjuvanted over non-adjuvanted vaccines in the specific antibodies formation is proved. However, cellular mechanisms, including parameters of the innate immunity, involved in the vaccine-induced immune response are not well studied. The human study of inactivated vaccines showed that both subunit vaccine and split vaccine induced cellular immune response, but adjuvanted vaccine containing Polyoxidonium had the greatest potential. Despite the fact that influenza vaccines must activate endosomal receptors, they cause non-specific activation of the surface TLRs. They can trigger intracellular signals leading to the induction of antiviral mechanisms and to the activation of the body’s protective resources against microbial infections. To assess the immunological efficacy of adjuvanted vaccines and humoral reactions to vaccination it is necessary to evaluate activation of cellular mechanisms of innate and adaptive immunity.

Background. Influenza prophylaxis with the use of quadrivalent vaccines (QIV) is increasingly being introduced into healthcare practice. Methods. In total, 32 healthy adults and 6 patients with common variable immunodeficiency (CVID) received adjuvant QIV during 2018–2019 influenza season. Depending on initial antibody titers, healthy volunteers were divided into seronegative (≤1:20) and seropositive (≥1:40). To evaluate immunogenicity hemagglutination inhibition assay was used. Results. All participants completed the study without developing serious post-vaccination reactions. Analysis of antibody titer 3 weeks after immunization in healthy participants showed that seroprotection, seroconversion levels, GMR and GMT for strains A/H1N1, A/H3N2 and B/Colorado, B/Phuket among initially seronegative and seropositive participants meet the criterion of CHMP effectiveness. CVID patients showed increase in post-vaccination antibody titer without reaching conditionally protective antibody levels. Conclusion. Adjuvant QIV promotes formation of specific immunity to vaccine strains, regardless of antibodies’ presence or absence before. In CVID patients search of new regimens should be continued.

Mucosal immunity plays a major role not only in the prevention but probably also in the outcomes of COVID-19. An enhanced production of secretory immunoglobulin A (sIgA) might contribute to the activation of the immune response mechanisms. To assess the levels of sIgA produced by epithelial cells in the nasal and pharyngeal mucosa and those measured in salivary gland secretions and to study the course of COVID-19 following the combined scheme of intranasal and subcutaneous administration of a bacteria-based immunostimulant agent. This study included 69 patients, aged between 18 and 60, who had moderate COVID-19 infection. They were divided into two groups: Group 1 (control group) included 39 patients who received only background therapy, and Group 2 was made up of 30 patients who received background therapy in combination with the Immunovac VP4 vaccine, a bacteria-based immunostimulant agent, which was given for 11 days starting from the day of admission to hospital. The levels of sIgA were measured by ELISA in epithelial, nasal and pharyngeal swabs, and salivary gland secretions at baseline and on days 14 and 30. The combined scheme of intranasal and subcutaneous administration of the Immunovac VP4 vaccine in the complex therapy of patients with COVID-19 is accompanied by increased synthesis of sIgA in nasal and pharyngeal swabs, more intense decrease in the level of C-reactive protein (CRP) and reduction in the duration of fever and length of hospitalization compared to the control group. Prescribing a immunostimulant agent containing bacterial ligands in complex therapy for COVID-19 patients helps to enhance mucosal immunity and improves the course of the disease.