Natural IgM Mediates Complement-Dependent Uptake ofFrancisella tularensisby Human Neutrophils via Complement Receptors 1 and 3 in Nonimmune Serum

Natural IgM mediates complement-dependent uptake of Francisella tularensis by human neutrophils via complement receptors 1 and 3 in nonimmune serum.

A fundamental step in the life cycle of Francisella tularensis is bacterial entry into host cells. F. tularensis activates complement, and recent data suggest that the classical pathway is required for complement factor C3 deposition on the bacterial surface. Nevertheless, C3 deposition is inefficient and neither the specific serum components necessary for classical pathway activation by F. tul...

Francisella tularensis Complement-Dependent Uptake of Natural IgM Mediates

Yersinia pestis targets neutrophils via complement receptor 3.

Yersinia species display a tropism for lymphoid tissues during infection, and the bacteria select innate immune cells for delivery of cytotoxic effectors by the type III secretion system. Yet, the mechanism for target cell selection remains a mystery. Here we investigate the interaction of Yersinia pestis with murine splenocytes to identify factors that participate in the targeting process. We ...

Complement Receptors 1 and 2 in Murine Antibody Responses to IgM-Complexed and Uncomplexed Sheep Erythrocytes

Early complement components are important for normal antibody responses. In this process, complement receptors 1 and 2 (CR1/2), expressed on B cells and follicular dendritic cells (FDCs) in mice, play a central role. Complement-activating IgM administered with the antigen it is specific for, enhances the antibody response to this antigen. Here, bone marrow chimeras between Cr2(-/-) and wildtype...

The Complement-dependent Bacteriolytic Activity of Normal Human Serum

The bacteriolytic activity of normal human serum on a rough strain of E. coli has been studied by a turbidimetric method. Bacteriolysis was found to be markedly dependent on ionic strength and pH, with optima at micro = 0.06 and pH 8.3-8.5, respectively. The method of cultivating the cells also influenced the rapidity of lysis. Lysis was temperature-dependent and was exhibited by all samples of...