Evaluation of pro/anti inflammatory responses after rectal administration of Mycobacterium bovis BCG
Abstract number: P1338
Movassagh H., Rafati S., Yazdanpanah B., Khadem F., Khanahmad Shahreza H., Pooya M., Sohrabi T., Rostami Baroei M., Moukhah R., Abolhassani M.
Objectives: Rectal administration of BCG induces a protective immune response against tuberculosis in animal models interestingly without any inflammatory complications. To understand the lack of inflammation we evaluated expression pattern of pro/anti inflammatory agents in the colorectal epithelial cell lines and fresh prepared epithelial cells (ECs) in presence or absence of intraepithelial lymphocytes (IELs). The regulatory mechanism of these expression profiles was studied by comparison of NFkB and PPARg activity.
Methods: IL-8 secretion was measured in Caco-2, HT-29 and SW-480 cell lines challenged with BCG by ELISA method. NFkB activity of the cell lines was assayed by DNA-based ELISA. IL-8 and IL-4 secretion was measured in guinea pig and macaque after rectal immunisation of BCG and also in their corresponding ECs and ECs+IELs. PPARg activity of macaque EC and ECs+IELs was measured by DNA-based ELISA. mRNA expression profile of some cytokines and chemokines in mice vaccinated with rectal BCG was determined using RNase protection assay (RPA).
Results: In response to BCG, IL-8 increased in a time dependent manner. This increase was corresponded by increase in NFkB activity. Guinea pig and macaque ECs showed the same behaviour by remarkable increases in IL-8 level. However ECs+IELs challenged with BCG didn't increase IL-8. We demonstrated a dramatic increase of 4 and 7 fold in IL-4 levels in ECs+IELs. Also PPARg activity was doubled during 24 hours in ECs. Two and seven days after BCG administration in mice, RPA was run on RNA from total colon, ECs and EC+IELs. The expression of pro-inflammatory cytokines IL-6, IL-18, IL-12p40, IL-1b, IFNg and MIF was increased in ECs lonely, whereas this effect was followed only by 2 days in ECs+IELs or in total colon. But in 7 days after BCG stimulation, the levels of these inflammatory agents were normalised. The same pattern was observed for the chemokines MIP-2 and MCP-1 while RANTES and IP-10 increased remarkably upto day seven. Anti-inflammatory cytokine IL-10, undetectable in ECs, was highly increased in ECs+IELs and also in total colon.
Conclusion: Rectal delivery of BCG induces an early balanced inflammatory process orchestrated by pro-inflammatory agents and Th2 mediated modulations that are controlled by a late IL-10 response. This balance is mainly due to IELs interactions which stable homeostasis at the colorectal mucosal surfaces.
|Session name:||18th European Congress of Clinical Microbiology and Infectious Diseases|
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