Protective efficacy of maternal antibodies induced by Salmonella toxoid (vaccine).

An attempt was made to evaluate the protective efficacy of maternal antibodies in chicks against salmonellosis. Layer chicks ageing 21 days were individually vaccinated with 100 microg of Salmonella enterica subspecies enterica serovar Weltevreden (BM 1643) toxoid adjuvanted with vitamin E subcutaneously. After 90 days of the primary vaccination the birds were given booster dose of the vaccine. The saline extract of the yolk of eggs laid by the vaccinated birds yielded agglutination and ELISA titres ranging from 43.2 +/- 5.33 to 75.2 +/- 6.26 and 4.987 x 10(3) +/- 0.54 to 5.89x103 +/- 0.56, respectively. Sera of chicks hatched from eggs laid by the vaccinated layers were also subjected to agglutination and ELISA. Agglutination and ELISA titres on the 5th day--post hatching (dph) were 21.6 +/- 1.75 and 4.025 x 10(2) +/- 0.59, while on the 10th dph titers were 13.6 +/- 1.65 and 1.21 x 10(2) +/- 0.60, respectively. It was also observed that only one out of 6 chicks died when challenged with 2 x 10(9) CFU of S. serovar Gallirarum at the age of 7 days showing 83.33% protection. Thus it can be concluded that passive immunity confided by Salmonella enterica subspecies enterica serovar Weltevreden (BM 1643) toxoid can protect chicks against salmonellosis during their early days of life.

Preparación toxoide a partir de la fracción hemorrágica del veneno de Bothrops asper (serpiente de América Central y del Sur) / Toxoid preparation from hemorrhagic fraction of Bothrops asper venom

Se describe una técnica para la preparación de un toxoide a partir de la fracción hemorrágica del veneno de Bothrops asper. Este método conserva un alto grado de inmunogenecidad aunque elimina los efectos letales. Ninguno de los animales vacunados con el toxoide de esta fracción presentó lesiones hemorrágicas cuando les fue inyectado el veneno de la fracción hemorrágica

Neutralization potency of Russell's viper venom toxoid antivenom, as compared with standard antivenom.

Rabbits were immunized with gamma (gamma) irradiated Russell's viper venom toxoid, adsorbed to aluminium phosphate adjuvant. Antibody (raised against toxoid inoculation) titer was compared to a commercial antivenom on the basis of its ability to neutralize hemorrhagic, necrotic and lethal effects of viper venom. Toxoid immunization (on day 0, 15 and 30) produced antivenom which showed approximately one-third antilethal, half antihemorrhagic and antinecrotic titers as compared to those of the commercial hyperimmunized, concentrated horse antivenom.

Comparative detoxification and protection of scorpion (Heterometrus bengalensis) venom by toxoid antiserum.

Comparative detoxification of scorpion venom by using different chemical agents was investigated. Detoxification by formalin showed the best optimum detoxifying agent. The formalin treatment resulted in 2.3% protein loss with 6-fold detoxification. This formal toxoid was immunogenic in rabbit giving high neutralizing antibodies as revealed from indirect haemagglutination test. Toxoid antiserum protected mice against the lethal action of venom. It also effectively antagonized the smooth muscle contractile response of venom, and venom-induced neuromuscular paralysis. This toxoid antiserum also protected the venom-induced cardiac arrest. The possibility of using this formal toxoid for antisera production and immunization for therapeutic use needs to be explored.