Cross neutralizing antibodies in hamsters vaccinated with leptospiral bacterins produced with three serovars of serogroup Sejroe

Abstract

Three leptospiral bacterins, produced with different serovars of Serogroup Sejroe, namely the hardjo (bacterin A), wolffi (bacterin B) and guaricura (bacterin C), were evaluated in male hamsters (Mesocricetus auratus) by comparing the agglutinating and neutralizing antibodies titers using microscopic agglutination (MAT) and in vitro growth inhibition (GIT) tests. The immunization schedule was based on two 1.0 mL doses of non-diluted formalin-inactivated whole culture bacterin given through subcutaneous route with 10-day interval. The challenge was performed ten days after the second vaccine dose, when the animals were inoculated with 0.2 mL of non-inactivated cultures of each serovar through intraperitoneal route. On the 21 st post-challenge day (PCD), all animals were bled and their sera were joined in pools (n=8) and tested by MAT and GIT. All vaccinated and control animals presented no clinical signs of leptospirosis after the challenge, but the serovar guaricura was isolated from the kidneys of control animals on the 21 st PCD. The MAT results showed cross agglutinins between serovars hardjo and wolffi, and between wolffi and guaricura. The GIT results revealed the presence of cross neutralizing antibodies between serovars wolffi or guaricura against hardjo, wolffi and guaricura. It was found that the tested strain of serovar hardjo did not produce detectable levels of neutralizing antibodies, indicating its poor immunogenicity.

Interference of vaccinal antibodies on serological diagnosis of leptospirosis in vaccinated buffalo using two types of commercial vaccines

“…The bacterins prepared with separated strains of Hardjo and Pomona serovars can promote a cross serological response. Nevertheless, the bacterin containing the serovar Wolffi induces higher titers of serum agglutinins against Hardjo serovar than against homologous serovar (11).…”

“…The vaccination, using commercial bacterin vacine against leptospirosis is the most important tool for this disease control in production animals (11). The present study used two commercial vaccines for bovine, one of those was prepared upon inactivated culture of six serovars of Leptospira spp and the other was composed by purified outer membrane of five serovars, both added with adjuvant.…”

Comparação entre a imunidade induzida em bovinos vacinados com bacterinas polivalentes comerciais e uma monovalente experimental

“…Siddique & Shah (1990) discutem que as vacinas não induzem uma mesma resposta soroló-gica contra todos as sorovariedades nelas contidas, podendo isso ocorrer devido a uma diferença na concentração antigênica final, ou pela supressão da resposta antigênica causada por uma sorovariedade sobre outra. O poder imunogênico segundo a amostra utilizada também deve ser levado em consideração, devido ao fato de que existem diferenças entre elas (Bolin et al 1989, Bolin et al 1991, Tabata 2002. De fato, Bolin et al (1991) referem que o aumento da massa antigênica da amostra Hardjoprajitino em uma vacina pode aumentar a antigenicidade e, consequentemente, a proteção conferida pela mesma.…”

Cinética da resposta imune humoral de cães jovens imunizados contra Leptospira interrogans

“…Para Tabata et al (2002) e Jaszczerski (2005 reações cruzadas podem ocorrer entre sorovares de um mesmo sorogrupo, que compartilhem antígenos em comum, com uma reativação da resposta imune direcionada a sorovares que não estejam presentes na vacina. Não é o caso do presente experimento, pois os sorovares Autumnalis e Tarassovi não pertencem a nenhum sorogrupo dos sorovares da vacina utilizada.…”