The aim of the study is to evaluate the effects of fish-derived lipids on antiviral immunity in healthy individuals. The study will be conducted on a group of 30 healthy volunteers recruited at the Department of Periodontology and Oral Diseases of the Medical University of Lodz. These people will take a composition of fish-derived oils (BioMarine®Medical Immuno & Neuro Lipids) at a dose of 0.5 ml / kg body weight per day in two / three divided doses for 90 days. BioMarine®Medical Immuno & Neuro Lipids is food for special medical purposes. At baseline and after 90 days, blood samples will be taken from the test subjects in order to evaluate the selected parameters of antiviral immunity.

The proposed clinical trial involving a nutritional intervention aims to assess the effect of a composition of fish oils containing, inter alia, WWKT omega-3 EPA and DHA, alkylglycerols and squalene on selected parameters of antiviral immunity in healthy people. The proposed daily dose of BioMarine®Medical Immuno & Neuro Lipids is 0.5 ml / kg b.w., which in practice for a person weighing 60 kg will mean a daily consumption of 30 mL of oil (including 1.6 g EPA, 9.1 g DHA, 2 5 g of alkylglycerols and 2.6 g of squalene).

At baseline, 15 ml of blood will be drawn in order to determine the parameters of the antiviral response.

The following immunological parameters will be tested:

1. NK cell activity using a mixed culture of PBMC with target cells (ability to inhibit tumor cell proliferation) assessed by flow cytometry.
2. Absolute number and percentage of NK cells (CD16 + CD56 +), cytotoxic (CD8 +), helper (CD4 +) lymphocytes, B (CD19 +) lymphocytes in the total pool of peripheral blood mononuclear cells (PBMC) by flow cytometry.
3. Ability of isolated PBMCs to synthesize INF-α, INF-β, INF-γ, IL-6 and TNF without and after polyclonal stimulation (PHA) and SARS-CoV-2 proteins (nucleocapside protein, SARS-CoV-2 spike protein ) in 42 h culture based on the determination of the level of protein released into the culture fluid and on the basis of mRNA expression for these factors. Analysis of PBMC post-culture supernatants (CBA technique with flow cytometer and gene expression analysis by qPCR).
4. Analysis of the composition of serum lipids and in PBMC lyophilisates after culture.

Blood sampling will be repeated after 90 days in order to determine the influence of the fish oils on the tested parameters.

Inclusion Criteria:

• absence of systemic diseases;
• no medications taken on a regular basis;
• correct body weight in relation to height - 18.5 ≤ BMI ≤ 24.9

Exclusion Criteria:

• lack of consent the patient'sto the examination.
• pregnant and lactating women;
• smokers or non-smokers for less than 5 years;
• any vaccinations in the period shorter than 1 month before the start of the study or planned during the study;
• lack of declaration on reducing fats in the diet and avoiding highly processed fats and fried products.