The most profound effect, irrespective of which experimental variant was analysed, occurred at the early stage of infection (24 h) at the lactoferrin concentration of 0.5 mg/mL (reduction of the titre at the preincubation stage by 1.5 log, at the adsorption stage by 1.542 log, and at the adsorption+post-adsorption stage by 2.208 log, that is, by approximately 96.8, 97.2 and 99.4%, respectively). This evidence concerns the gene LTF and infection.