Studies of Immunobiological Properties in <i>Francisella tularensis</i> Vaccine Strain 15 NIIEG under Extended Storage Conditions

Abstract

Investigated have been 8 cultures of Francisella tularensis strain 15 NIIEG (lyophilized in 1953, 1966, 1969, 1987, 1990, 2003, 2012, and 2013, respectively) stored at the State Collection of Microorganisms of the Scientific Center on Expertise of Medical Application Products. It is established that the majority of cultures has maintained their immunobiological properties. However, it is of note that liophilization does not prevent F. tularensis strain 15 NIIEG from changes in its residual virulence under extended storage. Revealed is the fact that LD50 for 7 cultures of tularemia microbe strain is within the limits of 100-250 microbial cells (m.c.). At the same time, residual virulence for the strain which dates back 1966 is 7.3·105 m.c. Immunogenic activity rates in F. tularensis 15 NIIEG strain cultures range within specified limits. Apart from this, F. tularensis 1987 strain does not comply with the established requirements to the “specific safety”, as subcutaneous inoculation with 5·109 m.c./ml caused death of Guinea pigs within the scheduled observation time. Demonstrated is the necessity in maintaining constant stability of the original immunobiological properties in Francisella tularensis strain 15 NIIEG under extended storage conditions.

Keywords

• штамм francisella tularensis 15 нииэг
• остаточная вирулентность
• иммунобиологические свойства
• francisella tularensis strain 15 niieg
• residual virulence
• immunobiological properties