RU2227160C1 - Strain of bacterium leptospira interrogans "mitronov" of serum group canicola for preparing vaccine - Google Patents

Abstract

FIELD: medicinal biotechnology, microbiology, vaccines. SUBSTANCE: invention can be used for preparing vaccine against leptospirosis. The strain L. interrogans is isolated from patient blood with leptospirosis. The strain heated at 56 C for 1 h elicits high immunogenic activity and protects experimental animals from death in administration to them of virulent leptospira in the dose that exceeds the lethal dose by 100-fold. Serum of animals immunized with experimental vaccine samples prepared from the strain "Mitronov" and containing antibodies raised against to leptospira of serum group Canicola exhibits high protective effect in experiment in golden hamster: ED₅₀ = 0.2. The strain is deposited in the collection NIIEM named for Hamalea AMS RF at = 480. Using the strain L. interragans = 480 provides preparing vaccine against epidemiologically actual pathogen of leptospirosis. EFFECT: valuable properties of strain and vaccine.

Description

The invention relates to the field of medical biotechnology and can be used to prepare a vaccine against leptospirosis.

Currently, a multivalent vaccine is used to prevent leptospirosis (see the Instructions for the Use of Leptospirosis Concentrated Inactivated Liquid Vaccine. Approved by the Head of the Department of State Control of Medicines and Medical Equipment R.U. Khabriev on October 16, 1998), which can be considered as an analogue of the invention. Leptospira serogroup Canicola are not included in this vaccine. However, the causative agents of this serogroup are of great epidemiological significance in the territory of the Russian Federation (see Onishchenko G.G., Monisov A.A., Gulchenko L.P., Fedorov Yu.M. // Mikrobiol., 1999, No. 4, p. 14-18).

The closest in essence to the claimed invention is the inactivated leptospirosis vaccine, which has been used for many years to prevent leptospirosis in humans, which included the leptospira serogroup Canicola (see Baryshev P.M. // Microbiol., 1980, No. 3, p. 52-57).

 The disadvantage of the drug is its low immunological effectiveness - 17.8%. Canicola serogroup leptospira antibodies were detected in only 1.6% of vaccinated people.

The invention is directed to obtaining an antigenically and immunogenically active and epidemiologically relevant strain of Leptospira serogroup Canicola, suitable for the preparation of a vaccine.

The strain is isolated from the blood of a person with leptospirosis. Leptospira deposited in the collection of the Institute of Epidemiology and Microbiology of the Academy of Medical Sciences of the Russian Federation named after N.F. Gamalei No. 480 of 05/25/2001

Strain characteristics

Morphological and cultural properties. Gram-negative spirochetes with characteristic morphology and motility. Cultivated on Tersky liquid nutrient medium with the addition of 5% rabbit serum at 28 ° C. In the stationary phase, the highest concentration is (3.0 ± 0.3) · 10 ⁷ leptospira in 1 ml.

Pathogenic properties. In experimental models, the strain is classified as moderately virulent: LD ₅₀ , which was determined by intraperitoneal administration to guinea pigs weighing 100.0-150.0 g, is 2 · 10 ⁴ microbial cells. The clinical manifestations of infection in guinea pigs are characterized by the appearance of fever in 100%, hemorrhage in 50% of animals.

Antigenicity. Antigenic activity of the strain is expressed: in response to a single intravenous administration to rabbits weighing 3.0 kg of a live leptospira culture containing 3 · 10 ⁷ microbial cells, antibodies appeared, the maximum of which occurred in the second or third week and the geometric mean titer of antibodies determined in the microagglutination reaction , was 1:51 200.

Immunogenic activity. The strain has a pronounced immunogenic activity. Killed by heating for 1 h at 56 ° C in a dose of 3 · 10 ⁷ , it protects against death and infection 100% of guinea pigs infected with Canicola serogroup leptospira in a dose 100 times higher than lethal.

A vaccine was obtained from the leptospira of the Mitron strain, which was tested in an animal experiment.

The vaccine can be obtained in the following way.

The Leptospira culture of the Mitron strain grown on Tersky medium and containing 3 × 10 ⁷ microbial cells in 1 ml was heated at 56 ° C for 1 h. The resulting heated vaccine was administered to 15 guinea pigs weighing 150.0 g at a dose of 1 ml intraperitoneally. Antibodies appeared in all experimental animals in response to the vaccine, the geometric mean titer of which in the microagglutination reaction was 1:79. After 30 days, all vaccinated and 10 control animals were injected with Canicola serogroup leptospira in a dose 100 times higher than lethal. All immunized guinea pigs remained alive for 30 days, and there were no symptoms of the disease. Leptospira were not isolated from the organs of slaughtered animals when plated on a nutrient medium. All control animals that received saline instead of the vaccine died.

The immunogenicity of the vaccine was studied by passive protection on golden hamsters. Animals 2 hours before the injection of a lethal dose of leptospira were injected intraperitoneally with guinea pig immune serum containing antibodies in a titer of 1:80. The preventive activity of serum from guinea pigs vaccinated with prototypes of the Golden Hamster vaccine, calculated by determining the ED ₅₀ , was 0.2.

Thus, the proposed strain has pronounced immunogenic properties and can be recommended for introduction into the vaccine.

Claims (1)

The bacterial strain Leptospira interrogans "Mitron" serogroup Canicola No. 480 (collection of leptospira NIIEM them. Gamalei AMS RF) for the preparation of the vaccine.