Submitted to: Veterinary Immunology and Immunopathology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/2/2006
Publication Date: 2/15/2007
Citation: Bastos, R.G., Johnson, W.C., Brown, W.L., Goff, W.L. 2007. Differential response of splenic monocytes and DC from cattle to microbial stimulation with Mycobacterium bovis BCG and Babesia bovis merozoites. Veterinary Immunology and Immunopathology. 115(3-4):334-345.
Interpretive Summary: The importance of the spleen in the immunity of cattle to blood parasites like Babesia bovis is well known, but the precise mechanisms involved are not fully understood. Recent studies have identified a number of cell populations within the spleen that work in concert to effect the demise of the invading pathogen. In this particular study, a well-known cell population and a newly identified population were shown capable of interacting with microbial pathogens including Babesia bovis but with different consequences. The newly defined cell population was shown capable of inducing other cells to produce products detrimental to the pathogen. Therefore, vaccines developed in the future must be capable of activating this cell population.
Technical Abstract: Both bovine peripheral blood monocyte-derived dendritic cells (DC) and myeloid DC from afferent lymph have been described, but resident DC from other bovine tissues have not been fully characterized. The spleen as a secondary lymphoid organ is central to the innate and acquired immune response to various diseases particularly hemoprotozoan infections like babesiosis. Therefore, we developed methods to demonstrate the presence of myeloid DC from the spleen of cattle and have partially characterized a DC population as well as another myeloid cell population with monocyte characteristics. The phenotypic profile of each population was CD13+CD172a+/-CD14-CD11a-CD11b+/-CD11c+ and CD172a+CD13+/-CD14+CD11a-CD11b+/-CD11c+, respectively. The CD13+ population was found exclusively in the spleen whereas the CD172a+ population was present at the same percentage in the spleen and peripheral blood. CD13+ cells developed a typical veiled appearance when in culture for 96 h. The two cell populations differed in their ability to produce nitric oxide and had a different pattern of cytokine mRNA when stimulated with Mycobacterium bovis BCG or Babesia bovis merozoites. The data demonstrate the presence of a myeloid splenic DC with attributes consistent with an immature status.