EXPERIMENTAL STUDY OF THE EARLY PROTECTIVE EFFECT OF A LIVE INFLUENZA VACCINE AGAINST A HETEROLOGOUS INFLUENZA INFECTION

Introduction. Live influenza vaccine (LAV) is an effective tool in the fight against influenza infection. LAIV is easy to administer, economical and fast to produce, and stimulates a systemic and local immune response. The present study examined early protection against heterologous influenza infection within 1 week of LAIV immunization.

Methods. We studied the expression and production of type I interferons in cell culture of monocyte-macrophage origin using ELISA. THP-1 cells were seeded at a concentration of 3x106/ml and LAIV (6 EID50/1 ml) was added after 48 hours. Mice were immunized intranasally under light ether anesthesia with the vaccine virus A/17/South Africa/2013/01(H1N1)pdm09, obtained from the collection of viruses of the Department of Virology of the Federal State Budgetary Institution “IEM” at a dose of 6 EID50. Infection was carried out on the 6th day after immunization with the A/Indonesia/5/2005(H5N1) IDCDC-RG2 virus.

Results. When both the vaccine virus and the parent virus A/South Africa/3626/2013(H1N1)pdm09 were introduced into THP-1 cell culture, an increase in the production of early cytokines and type I interferon was observed. Immunization with LAIV completely protected mice on day 6 after immunization against lethal infection with a heterologous influenza virus.

Conclusion. The data obtained may indicate the benefit of using LAIV during the seasonal rise of acute respiratory viral infections (ARVI) due to stimulation of innate immune factors.