- Email: [email protected]
Generation of B cells in bovine fetuses
268
Abstracts / Veterinary Immunology and Immunopathology 128 (2009) 211–347
immune cells (macrophages, B cells, CD4+ and CD8+ T cells) in infiltrating the site of vaccination.
5. Antigen presentation and dendritic cells, effector cells, B and T cells, NK and NK T cells, immunoregulatory cells
doi:10.1016/j.vetimm.2008.10.123
Generation of B cells in bovine fetuses Anna Ekman, Antti Iivanainen ∗
Effect of transferrins on Chlamydophila psittaci Delphine Beeckman Caroline, V.A.N. Droogenbroeck, Daisy Vanrompay ∗ Ghent University, Department of Molecular Biotechnology, Coupure Links 653, 9000 Ghent, Belgium Keywords: Transferrins; Chlamydophila psittaci; Respiratory disease
Department of Basic Veterinary Sciences, University of Helsinki, Helsinki, Finland Keywords: B cells; Ontogeny; CD79a; CD21; RAG-1; RAG-2 E-mail address: antti.iivanainen@helsinki.fi (A. Iivanainen).
Species: Avian Objectives: the effect of ovotransferrin (ovoTF), human lactoferrin (hLF) and bovine lactoferrin (bLF) on the obligate intracellular Gram-negative bacterium Chlamydophila (Cp.) psittaci was evaluated using African Green Monkey (BGM) kidney epithelial cells and chicken macrophages (HD11 cells). Subsequently, transferrins were used to prevent a Cp. psittaci infection in specified pathogen free (SPF) turkeys. Results: firstly, the effect of transferrins on extracellular bacteria was evaluated. Pre-incubation of Cp. psittaci with 0.5–5 mg/ml ovoTF prior to infecting BGM cells significantly lowered the infection rate. For both lactoferrins, the infection rate could only be reduced with 5 mg/ml, albeit not significantly as compared to the infection rate created by the untreated bacteria. Secondly, transferrins were tested for their ability to influence bacterial adhesion and entry in HD11 cells. Maximal non-cytotoxic and non-bactericidal concentrations of 0.05 mg/ml ovoTF and 0.5 mg/ml hLF and bLF were used. Overall, ovoTF was more effective than human and bovine LF in inhibiting bacterial attachment and cell entry and the latter was accompanied by a dosedependent reduction of actin recruitment at the bacterial entry site. However, once bacteria had entered HD11 cells, transferrins had apparently no effect on intracellular replication. Thirdly, ovoTF being the most effective anti-Cp. psittaci transferrin in vitro, was evaluated for protecting SPF turkeys against an aerogenic chlamydial infection. Results of the in vivo study will be presented. Conclusion: present findings suggest a possible role for transferrins and especially ovoTF, in preventing avian Cp. psittaci infections.
Species: Ruminants The human and murine bone marrow generates naïve B cells throughout postnatal life. In many other Species, however, B cell ontogeny is apparently limited to the fetal period, founder B cells are few in number and the recombinational repertoire is limited. At late fetal and early postnatal age, the preimmune repertoire is diversified through post-recombinational mechanisms. The B cell population is dramatically expanded in various gut associated lymphoid tissues, i.e. in avian bursa, rabbit appendix and ruminant ileal Peyer’s patch (IPP). Despite the well established role of ruminant IPP in the generation of B cell mass and preimmune repertoire, very little specific information is available on the ontogeny of ruminant B cells. We have systematically assessed hematopoietic tissues of bovine fetuses from different developmental stages for signs of B lymphopoiesis. The material consisted of 29 fetuses ranging from 85 to 280 days of embryonic development. By a combination of immunohistochemistry and quantitative RT-PCR, a set of markers characterizing B cell differentiation was analysed. Surface IgM positive immature B cells were detected during the third trimerster in spleen and in lymph nodes. CD21-positive, CD79a-positive and surface IgM-low or IgM-negative serial sections in spleen and lymph nodes suggest the presence of pre-B cells during the second trimester. Quantitation of RAG-1 and RAG-2 expression revealed low levels of recombination activation gene activity in spleen, lymph nodes and the bone marrow but not in the terminal small intestine. Even though we did not purify the IPP in this work, the results suggest that massive B lymphoid differentiation characterized by RAG mediated immunoglobulin gene recombination does not take place in fetal bovine IPP. It is possible, however, that low levels of B lymphoid differentiation occurs in fetal spleen, bone marrow and lymph nodes.
doi:10.1016/j.vetimm.2008.10.124
doi:10.1016/j.vetimm.2008.10.125
E-mail address: rompay).
[email protected]
(D.
Van-
Abstracts / Veterinary Immunology and Immunopathology 128 (2009) 211–347
immune cells (macrophages, B cells, CD4+ and CD8+ T cells) in infiltrating the site of vaccination.
5. Antigen presentation and dendritic cells, effector cells, B and T cells, NK and NK T cells, immunoregulatory cells
doi:10.1016/j.vetimm.2008.10.123
Generation of B cells in bovine fetuses Anna Ekman, Antti Iivanainen ∗
Effect of transferrins on Chlamydophila psittaci Delphine Beeckman Caroline, V.A.N. Droogenbroeck, Daisy Vanrompay ∗ Ghent University, Department of Molecular Biotechnology, Coupure Links 653, 9000 Ghent, Belgium Keywords: Transferrins; Chlamydophila psittaci; Respiratory disease
Department of Basic Veterinary Sciences, University of Helsinki, Helsinki, Finland Keywords: B cells; Ontogeny; CD79a; CD21; RAG-1; RAG-2 E-mail address: antti.iivanainen@helsinki.fi (A. Iivanainen).
Species: Avian Objectives: the effect of ovotransferrin (ovoTF), human lactoferrin (hLF) and bovine lactoferrin (bLF) on the obligate intracellular Gram-negative bacterium Chlamydophila (Cp.) psittaci was evaluated using African Green Monkey (BGM) kidney epithelial cells and chicken macrophages (HD11 cells). Subsequently, transferrins were used to prevent a Cp. psittaci infection in specified pathogen free (SPF) turkeys. Results: firstly, the effect of transferrins on extracellular bacteria was evaluated. Pre-incubation of Cp. psittaci with 0.5–5 mg/ml ovoTF prior to infecting BGM cells significantly lowered the infection rate. For both lactoferrins, the infection rate could only be reduced with 5 mg/ml, albeit not significantly as compared to the infection rate created by the untreated bacteria. Secondly, transferrins were tested for their ability to influence bacterial adhesion and entry in HD11 cells. Maximal non-cytotoxic and non-bactericidal concentrations of 0.05 mg/ml ovoTF and 0.5 mg/ml hLF and bLF were used. Overall, ovoTF was more effective than human and bovine LF in inhibiting bacterial attachment and cell entry and the latter was accompanied by a dosedependent reduction of actin recruitment at the bacterial entry site. However, once bacteria had entered HD11 cells, transferrins had apparently no effect on intracellular replication. Thirdly, ovoTF being the most effective anti-Cp. psittaci transferrin in vitro, was evaluated for protecting SPF turkeys against an aerogenic chlamydial infection. Results of the in vivo study will be presented. Conclusion: present findings suggest a possible role for transferrins and especially ovoTF, in preventing avian Cp. psittaci infections.
Species: Ruminants The human and murine bone marrow generates naïve B cells throughout postnatal life. In many other Species, however, B cell ontogeny is apparently limited to the fetal period, founder B cells are few in number and the recombinational repertoire is limited. At late fetal and early postnatal age, the preimmune repertoire is diversified through post-recombinational mechanisms. The B cell population is dramatically expanded in various gut associated lymphoid tissues, i.e. in avian bursa, rabbit appendix and ruminant ileal Peyer’s patch (IPP). Despite the well established role of ruminant IPP in the generation of B cell mass and preimmune repertoire, very little specific information is available on the ontogeny of ruminant B cells. We have systematically assessed hematopoietic tissues of bovine fetuses from different developmental stages for signs of B lymphopoiesis. The material consisted of 29 fetuses ranging from 85 to 280 days of embryonic development. By a combination of immunohistochemistry and quantitative RT-PCR, a set of markers characterizing B cell differentiation was analysed. Surface IgM positive immature B cells were detected during the third trimerster in spleen and in lymph nodes. CD21-positive, CD79a-positive and surface IgM-low or IgM-negative serial sections in spleen and lymph nodes suggest the presence of pre-B cells during the second trimester. Quantitation of RAG-1 and RAG-2 expression revealed low levels of recombination activation gene activity in spleen, lymph nodes and the bone marrow but not in the terminal small intestine. Even though we did not purify the IPP in this work, the results suggest that massive B lymphoid differentiation characterized by RAG mediated immunoglobulin gene recombination does not take place in fetal bovine IPP. It is possible, however, that low levels of B lymphoid differentiation occurs in fetal spleen, bone marrow and lymph nodes.
doi:10.1016/j.vetimm.2008.10.124
doi:10.1016/j.vetimm.2008.10.125
E-mail address: rompay).
[email protected]
(D.
Van-