Abstract

EXPERIMENTAL CHRONIC TUBERCULO-TYPHOID EXPOSURE IN A LAPIAN IMMUNE EVALUATION MODEL II: CUMULATED EFFECT

Dr. Ibrahim M.S. Shnawa, Dr. Zainab Khudhur Ahmed Al-Mahdi

Abstract

Aim of the Study: To evaluate the possible influences of chronic cumulated exposure to lower concentrations of tuberculin on the immune response to typhoid antigen in a lapin model. Methods: Residual tuberculin concentration of 0.00005 ,0.0005, 0.005 and 0.05 IU were nasally applied through aerosolizer in a week wise manner to ten newzeland white rabbits, five of which were left four days then immunized with S. typhi “O” antigen (group I). The other five however were left as such for one more week (Group II). Ten other neuzland white rabbits were equally subdivided in to S. typhi immunized rabbits (Group III) and saline injected rabbits as control (Group IV). A set of immune function test were performed to the four groups of these rabbits. Result: The cumulated tuberculin exposure (Group II) lead to increase of NBT neutrophil phagocytosis ; significant LIF percentage; E.rossete count; IL-1α, IL-12 and IL- 10 but not IL-4 and skin DTH. While combined Tuberculo-Typhoid exposure (Group I) lead to increase in NBT, E.rosette and IgM anti S. typhi “O” but not DTH. Both of the exposure modalities shifts cytokine balance towards proinflammatory cytokines. Conclusion: The major immune feature of these exposure modalities was: 1- Immunomodulation, 2-T-Cell competition, 3-Cytokine unbalance and 4- inhibition of IgM class switching to IgG.

Keywords: Experimental Chronic, Tuberculo-Typhoid Exposure, lapian Evaluation Model.