Examination of the immunogenicity of experimental subunit vaccine against newcastle disease virus

Abstract

The of immunogenicity of the experimental subunit vaccine against Newcastle Disease virus was studied in a biological assay on 180, Issa Brown chickens, (80 chickens of 21 days old, and 100 chickens of 11 days old) and 50 Hybro chickens of 21 days old. The experimental subunit was prepared from purified glycoprotein subunits isolated from experimental subunit vaccine was prepared from purified glycoprotein subunits isolated from the outer envelopes of Newcastle Disease viruses, La Sota strain, which had a hemagglutinating titre of 128 HJ/0,1 ml. Antigens were adsorbed on the adjuven Al (OH)3, dissolved in 100 mmol/l PBS. Two groups of 22 and 25 experimental Issa Brown chickens, were immunized with 0,2 ml of the subunit vaccine i/m per animal, and revaccinated on day 21 of the assay. The group of 22 experimental chickens was artifically infected on day 28 after the vaccination with 200 00 EID of the virulent strain of the Newcastle Disease virus - Hertz 33 (i/m per animal). Survival percentage after the artifical infection was 95,4%. The geometric mean titres of the HI antibodies against the Newcastle Disease virus (Gmt log 2/25 ml) in the sera of the first group of 22 vaccinated chickens: were as follows: on day 7 after the vaccination 2,80, on day 21-2,70 and on day 28-4,0, and in the sera of the second group of vaccinated chickens on day 7-2,87, on day 21-2,78, and on day 28-4,17. The second two groups of 18 and 15 experimental Issa Brown chickens served as the negative and positive controls in the assay. The other part of the examination was carried out in a biologycal assay on chicken. Of the Hybro breed, 21 days old.Two groups of 16 and 14 experimental chickens immunized in the described way, were artificially infected after 21 days with 200 000 (the first group) and 400 000 (the second group) EID50 of the Hertz 33 strain (i/m per animal). Survival after the artificial infection was 94% in the first group, and 74% in the second group. Two other groups of 10 Hybro chickens served as the negative and positive controls in the assay. A comparative study of the subunit vaccine and of the TB-Mukteswar vaccine was carried out inaa biologycal assay on two groups of 50 experimental Issa chickens Brown, 11 days old. Survival after the artificial infection with 200 000 EID50 of NDV, Hertz 33 strain (i/m per animal) in the chickens vaccinated with subunit vaccine was 100% white in the chickens immunized with TB-Mukteswar vaccine survival was 80%.