Fekadu Desta
Addis Ababa University, Ethiopia
Title: Poster: Comparison of immune cells subsets, ex-vivo and in-vivo expression of T cell activation and memory marker between LNC and corresponding PBMC from calves exposed to natural mycobacterium bovis infection
Biography
Biography: Fekadu Desta
Abstract
Cell-mediated immunity and development of necrotic granulomas in Mycobacterium bovis (M. bovis) infected lymph node (LN) is pathognomonic for bovine tuberculosis (BTB). This delayed hypersensitive host response involves a complex interaction of cellular and immune mediators within systemic circulation and LN. Hence, tuberculosis immunological response should be independently investigated at the peripheral blood and LN tissue level. The objective of this study was, therefore, to compare the cell surface and cytokine expression between immune cell from peripheral blood and lymph node cells (LNC) from calves on BCG efficacy trial. Twenty pairs of peripheral blood mononuclear cells (PBMC) and) LNC from M. bovis naturally infected calves during BCG vaccine experiment trial were isolated and investigated in two phases of the flowcytometry experiment. In the first phase of a flow-cytometry experiment the proportion of ex-vivo CD25+ expressing cells was significantly higher (P<0.05) in CD4+ and CD8+ T node than that of peripheral blood. However, such difference in CD25+ expression was not observed in WC1 γδ T cells. Contrary to CD25+ ex-vivo expression, in-vitro IFN-γ and TNF-α producing cells were greater (P<0.05) in T cells of the peripheral blood than T cells of lymph node after PMA + ionomycin stimulation. This difference in IFNγ and TNFα responses was also statistically significant between a vaccinated and non-vaccinated group. An IL-4 producing cell was not evident in PBMC and LNC. During the second phase of flow-cytometry experiment additional surface marker; CD2, CD21, CD205, CD335 and CD1W2 were included to add more panels for immune cell subset. The second experiment revealed that PBMC CD4–WC1+ and CD8–WC1+ γδ T cells and CD205+D1W2+ DC subset exhibited lower percentage than γδ T cells and DC of LNC respectively (p=0.0001, p=0.0061). However, PBMC CD335+CD2+ NKT cells subset exhibited a higher percentage than NKT cells of LNC (p=0.0129). No difference was observed between groups in the percentage of the rest of T-cell and B-cell (p>0.05). Findings of this study suggest the existence of phenotypic immune compartmentalization between the two tissue compartments.