RU2127757C1 - Strain a/47/nanchang/95/13 (h3n2) for production of live antiinfluenza intranasal vaccine for children - Google Patents

Abstract

FIELD: medicine, virology, vaccines. SUBSTANCE: invention relates to preparing live antiinfluenza intranasal vaccine for children that corresponds to an actual virus A/Nanchang/933/95 (H3N2). Vaccine strain A/47/Nanchang/95/13 (H3N2) is a reassortant obtained by breeding epidemic virus A/Nanchang/933/95 (H3N2) with cold-adopted and temperature-sensitive virus A/Leningrad/ /134/47/57 (H2N2) - an attenuation donor. Strain is harmless for children and its properties ensure a possibility to obtain reassortant vaccine strains from the again appearing epidemic viruses. Strain A/47/Nanchang/95/13 (H3N2) is actively multiplicated in developing chicken embryos at optimal temperature 34 C. Strain shows temperature-sensitivity and cold-adaptation. From an epidemic virus reassortant inherited two genes encoding surface proteins (hemagglutinin and neuraminidase) and six genes encoding nonglycosylated proteins from attenuation donor. Strain A/47/Nangchang/95/13 (H3N2) is an areactogenic for children at intranasal administration. Vaccine strain A/47/Nanchang/95/13 (H3N2) by its biological properties and reactive indices corresponds to requirements for vaccine strain according Pharmacopoeia points 42-298 VS-89 with respect to vaccine for intranasal using for children 3-14 ages. EFFECT: strain indicated above, enhanced effectiveness of vaccine proposed. 1 tbl, 1 ex

Description

 The invention relates to medical virology and can be used in healthcare for the prevention of epidemic influenza among children with a live intranasal influenza vaccine from strain A / 47 / Nanchang / 95/13 (H3N2). The well-known strain A / 47 / Shangdong / 93/1 (H3N2) - prototype [1] - lost antigenic activity and therefore will not be able to cause a protective reaction during an influenza epidemic caused by a strain of influenza virus similar to A / Nanchang virus / 933/95 (H3N2).

 The problem to which the invention is directed, is to obtain a vaccine strain of the actual antigenic variety based on the epidemic virus A / Nanchang / 933/95 (H3N2).

 The vaccine strain A / 47 / Nanchang / 95/13 (H3N2) was obtained by genetic reassortment of the epidemic virus A / Nanchang / 933/95 (H3N2) with a cold-adapted strain A / Leningrad / 134/47/57 (H2N2) - an attenuation donor - with subsequent selection in the presence of antisera to the virus A / Leningrad / 134/47/57 (H2N2). The attenuation donor is a cold-adapted temperature-sensitive strain of influenza virus A / Leningrad / 134/47/57 (H2N2), which is approved for the production of harmless live internasal vaccines for children [2].

Using restriction analysis of DNA copies of vaccine and parental strains, it was found that vaccine strain A / 47 / Nanchang / 95/13 (H3N2) inherited 6 genes encoding internal proteins (PB1, PB2, PA, NP, M, NS) from an attenuation donor A / Leningrad / 134/47/57 (H2N2) and 2 genes encoding surface proteins - HA (hemagglutinin) and NA (neuraminidase) - from the epidemic virus A / Nanchang / 933/95 (H3N2). Hemagglutinin in rtga is identical to virus A / Nanchang / 933/95 (H3N2), the antiserum of which is completely neutralized. The strain is temperature-sensitive (the difference in the rate of infectious activity at 34 ^o C and 40 ^o C is 8.0 lg EID ₅₀ / 0.2 ml) and cold-adapted (the difference in the rate of infectious activity at 34 ^o C and 25 ^o C is 3.0 lg EID ₅₀ / 0.2 ml).

 Thus, the strain A / 47 / Nanchang / 95/13 (H3N2) presented by the vaccine is characterized by a combination of useful features necessary for the vaccine strain: the antigenic specificity of the surface proteins of the epidemic virus A / Nanchang / 933/95 (H3N2), the genome structure optimal for reassortant vaccine strains, heat sensitivity and cold adaptability, which correlates with attenuation for humans, characteristic of an attenuation donor.

 The morphology of the strain is polymorphic, typical of the influenza virus.

Infectious activity during reproduction in developing chicken embryos at 34 ^o C for 48 hours - 8.5 lg EID ₅₀ / 0.2 ml

 Hemagglutinating activity - 1: 512.

 The strain exhibits genetic stability of biological traits after 5 passages on chicken embryos (when using large infectious doses).

 Strain A / 47 / Nanchang / 95/13 (H3N2) is reactogenic when administered intranasally to children 3-14 years old.

Example. A group of 94 children aged 3-14 years old were vaccinated intranasally in a volume of 0.5 ml with the recombinant vaccine strain A / 47 / Nanchang / 95/13 (H3N2) with an infectious activity of 8.5 lg EID ₅₀ / 0.2 ml. A group of children of the same age of 89 people received a placebo.

Strong temperature reactions with increasing temperature above 38.5 ^o C were not observed. Medium reactions with a short-term temperature increase in the range of 37.6 - 38.5 ^o C were observed in 1.8% of cases. Weak temperature reactions (up to 37.5 ^o C) - in 7.5% of cases. The reactogenicity index (the difference in the percentage of average reactions in vaccinated vaccines and received placebo) was 0% (table 1).

 Thus, the vaccine strain A / 47 / Nanchang / 95/13 (H3N2) in terms of reactogenicity meets the requirements for vaccine strains with pharmacopeia article FS 42-298 BC-89 for live influenza vaccine for intranasal use in children 3-14 years old.

Literature
1. Strain A / 47 / Shangdong / 93/1 (H3N2) for the production of live influenza intranasal vaccine for children. RF patent N 2065498, 08.20.1996, BI N 23.

 2. Alexandrov G.I., Klimov A.I. Live flu vaccine. - SPb .: Science. -1994. -151 p.

Claims (1)

 The strain of influenza virus A / 47 / Nanchang / 95/13 (H3N2) GISK N 1002 (State Institute of Standardization and Control named after L.A. Tarasevich), used to obtain live influenza intranasal vaccine for children.

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