PROTECTIVE IMMUNITY TO BRUCELLA-OVIS IN BALB C MICE FOLLOWING RECOVERY FROM PRIMARY INFECTION OR IMMUNIZATION WITH SUBCELLULAR VACCINES/

Citation
Mpj. Debagues et al., PROTECTIVE IMMUNITY TO BRUCELLA-OVIS IN BALB C MICE FOLLOWING RECOVERY FROM PRIMARY INFECTION OR IMMUNIZATION WITH SUBCELLULAR VACCINES/, Infection and immunity, 62(2), 1994, pp. 632-638
Citations number
53
Categorie Soggetti
Immunology,"Infectious Diseases
Journal title
ISSN journal
00199567
Volume
62
Issue
2
Year of publication
1994
Pages
632 - 638
Database
ISI
SICI code
0019-9567(1994)62:2<632:PITBIB>2.0.ZU;2-X
Abstract
Experiments were performed with BALB/c mice to elucidate the roles of humoral and cell-mediated immune responses in the acquisition of prote ctive immunity to Brucella ovis and to compare infection immunity with immunity developed through vaccination with a hot saline extract (HS) of B. ovis. Mice convalescing from a primary infection with B. ovis d isplayed a high level of resistance to reinfection, as evidenced by sp lenic bacterial counts decreased over 10,000-fold from control groups at 2 weeks after challenge. Passive transfer assays revealed that prot ection was mediated by both T lymphocytes and antibodies but that anti bodies had a substantially gl eater role on the basis of log units of protection that were transferred. Antibodies specific for HS proteins in sera from convalescent mice were predominantly of the immunoglobuli n G 2a and 3 isotypes. Vaccination with HS conferred good protection a gainst B. ovis, but protection was greatly enhanced by the incorporati on of QS-21 or other adjuvants. Protection provided by the HS vaccine resulted largely from immune responses to its protein moieties. A crit ical evaluation of the protective efficacy of the rough lipopolysaccha ride component of HS was precluded by its poor immunogenicity in BALB/ c mice. HS-QS-21 afforded protection against challenge infection with B. ovis as good as that which developed after a primary infection and as good as or better than that provided by attenuated Brucella meliten sis vaccine strain Rev 1. Passive transfer experiments confirmed that the magnitudes of both humoral and cell-mediated forms of protective i mmunity were equivalent in mice vaccinated with HS-QS-21 and those rec overing from a primary infection. Protective immunity to B. ovis in mi ce therefore resembled that to Brucella abortus, except that the relat ive roles of humoral and cell-mediated immunity, rather than being equ ivalent, were shifted toward a greater role for antibodies.