Role of T cells in the adjuvant effect ofbacillus firmus on the immune system of mice: Intranasal and intratracheal immunization study with ovalbumin

Abstract

Functions of T cells were determined after intranasal and intratracheal immunization of mice with ovalbumin (Ova) and Bacillus firmus (Bf), a Gram-positive nonpathogenic bacterium of the external environment, or delipidated Bf (dBf) as adjuvants, with the aim to elucidate the mechanism of support of Ova-specific antibody production caused by Bf that had been observed in an identical experiment. Neither Bf nor dBf in a mixture with Ova stimulated Ova-specific T-cell response tested as antigen-specific blast transformation. By contrast, a mild polyclonal stimulation was observed in splenocytes from mice given dBf. In vitro incubation of splenocytes with 100 micrograms (but not 10 micrograms) of Bf or dBf led to a highly significant inhibition of proliferation below the control level in all groups of animals. Supernatants of splenocyte cultures were further tested for cytokine production. IL-10 and IFN-gamma were released after in vitro challenge with dBf and in some cases also with Bf. Analysis of sera demonstrated that administration of Ova + adjuvant brought about an increase in anti-Ova IgG1, IgG2a and IgG2b whereas treatment with Ova alone caused a rise in IgG1 only. The role of Bf or dBf in the enhancement of antigen-specific antibody production could be in influencing macrophages and inducing cytokine milieu composed of IL-10, IFN-gamma and other factors that leads to a bystander stimulation of specifically activated Ova-B cell receptor (Ova-BCR)-bearing cells.

Protective and cross-protective mucosal immunization of mice by influenza virus type A with bacterial adjuvant

“…This bacterium is absolutely harmless, inactivated bacteria do not lower the viability of cells in tissue culture and mice tolerate very well high doses of both inactivated and live bacteria [24][25][26][27].…”

Immune response after adjuvant mucosal immunization of mice with inactivated influenza virus

“…This is the result of a specific antibody response. Our previous studies showed that, in concentrations used in vivo, BF does not cause polyclonal activation of B lymphocytes [23].…”

“…Isolated RNA was treated with RNase-free DNase (Qiagen) and stored in aliquots at −70 • C. RNA integrity and yield were assessed by UV spectrophotometry (Thermo spectronic-Biomate 5) and ethidium bromide staining. DNase-treated RNA was reversetranscribed with oligo(dT) 23 primers using enhanced avian HS RT-PCR kit (Sigma). PCR amplification was performed with specific primers (IL-2, IL-4, IL-10, INF-␥, ␤-actin and iNOS), PCR buffer (Sigma) and HotStartTaq polymerase (Qiagen) in 35 cycles.…”