The impact of adjuvanted and non-adjuvanted influenza vaccines on <i>in vitro</i> lymphocyte immunophenotype

Vaccination is the most effective method of influenza prophylaxis resulting in reduced frequency and severity of complications. Currently, for the prevention of influenza, inactivated split and subunit vaccines as the safest and promoting formation of protective level of strain-specific virus neutralizing antibodies are used. It is known that not all inactivated vaccines are effective enough for select human groups. While nowadays the level of public health is low, there is a need to improve the effectiveness of vaccines that should activate all chains of the immune system. In order to enhance intensity of influenza virus strain-specific antibody production, adjuvant vaccines exerting other mechanisms to activate humoral and cellular immunity compared to non-adjuvant vaccines have been used. The aim of the study was to examine lymphocyte immunophenotype in 27 healthy donors treated with polymer-subunit (immunoadjuvant) and non-adjuvanted split and subunit influenza vaccines. Materials and methods. Peripheral blood lymphocyte subpopulations were studied in vitro by flow cytometer FC-500 Cytomics (Beckman Coulter, USA) using FITC- and PE-labeled monoclonal antibodies (mAbs). Results. All examined influenza vaccines activate the effectors of cellular immunity, increasing the number of NK-cells (CD16/56), NKT-lymphocytes (CD3/CD16/56), B-lymphocytes (CD45/CD20), activated (CD3/HLA-DR) and cytotoxic (CD8/HLA-DR) T-lymphocytes, as well as cells bearing early activation marker (CD45/CD25). Among them the immunoadjuvant vaccine showed the greatest potential to induce cellular response eliciting regulatory mechanisms that prevent hyperactivation, stimulating growth of NK (CD16/56), NKT-cells (CD3/CD16/56), B-lymphocytes (CD45/CD20), activated (CD3/HLA-DR) and cytotoxic (CD8/HLA-DR) T-lymphocytes, T-regulatory cells (Tregs, CD4/CD25/Foxp3). Conclusion. Vaccination against influenza besides the formation of specific antibodies render a transient, immunomodulating effect that is more noticeable after immunoadjuvant vaccine. It can be assumed that vaccination of people with dysfunctions of the immune system an additional prophylactic effect will be observed.