Intratracheal and intranasal immunization with ovalbumin conjugated withBacillus firmus as a carrier in mice

Abstract

Inactivated Bacillus firmus (BF), G+ nonpathogenic bacterium of the external environment, was coupled to ovalbumin (OVA) and used in immunization experiments as antigen carrier. Balb/c mice were immunized thrice intra-tracheally and intra-nasally with conjugates of OVA and BF. Surprisingly, administration of OVA-BF conjugates inhibited anti-OVA IgG response in both sera and mucosal secretions if compared to an exposure to OVA alone. The suppression of antigen-specific antibody production was accompanied by promotion of TH1 phenotype.

Adjuvant effect of Bacillus firmus on the expression of cytokines and toll-like receptors in mouse nasopharynx-associated lymphoid tissue (NALT) after intranasal immunization with inactivated influenza virus type A

“…Even in high doses inactivated bacteria do not damage the viability of tissue culture cells; and mice tolerate high doses very well of not only inactivated but also live bacteria (intraperitoneal or mucosal application, Prokesova -not published data). The excellent adjuvant properties of this bacterium were first described for intratracheal immunization of mice in combination with the protein antigen ovalbumin [20,21], and later for intratracheal immunization with inactivated type B and also type A influenza viruses. Immunization with inactivated influenza viruses in combination with the adjuvant induced a high antibody response, both in serum (high production of class IgG antibodies) and in respiratory tract mucosa (high production of class IgA antibodies) and provided in vivo protection against influenza infection.…”