The marginal sinus is an important route by which blood-borne particles selleck inhibitor and nonlymphoid cells first enter the spleen (17). Our observations in naïve calves are consistent with recent intravital imaging studies in rodent models (54–56) which document the early interactions and trafficking of several marginal zone cell types and the importance of these events to the splenic immune responses. Our results, however, do not exclude the potential relevance of initial antigen interaction with other zonal cell populations (e.g., PALS lymphocytes) to the acute response of naïve calves to B. bovis. In summary, the results of
this immunohistological investigation have demonstrated dynamic change in the distribution of several cell click here types thought to be important to the acute spleen-dependent
response of calves to B. bovis infection. In particular, unambiguous redistribution of iDC to regions where parasites first enter the spleen and evidence for further maturation and antigen processing seem noteworthy. The remarkable similarity of these acute splenic responses of calves to B. bovis and those reported in mice responding to P. chabaudi indicates that redistribution of splenic cells is central to the acute immune response of naïve animals to haemoparasite infection. This work was supported by C-X-C chemokine receptor type 7 (CXCR-7) USDA-ARS-CWU-5348-32000-010-00D. The authors especially recognize the expert technical contributions of Sallie Bayly who assisted in the splenic transposition surgeries, Tom Truscott for immunohistochemical advice, and Thomas Wilkinson and Rob Houston for MRI techniques. We thank Duane Chandler and Amy Hetrick for their contributions to the care and use of the animals. The authors thank Dr William C. Davis for his critical review of the manuscript. Mention of trade names
or commercial products or enterprises in this article is solely for the purpose of providing specific information and does not imply recommendation or endorsement by the US Department of Agriculture. “
“Toll-like receptor (TLR) signalling is involved in first-line defence against Leishmania parasites by triggering NF-κB activation and downstream production of proinflammatory cytokines. Experimental models of visceral leishmaniasis (VL) support a protective role for TLRs 2, 4 and 9 in host immune responses to Leishmania infection. There are limited data available on expression of these TLRs in human VL, particularly in sites of infection, such as the spleen. This study aimed to determine whether the expression of mRNA encoding the expression of TLRs 2, 4 and 9 was altered in VL and compare expression patterns in splenic biopsies and peripheral blood mononuclear cells.