Properdin factor D,1 a 23,500 tool wt euglobulin (6), interacts with properdin factor B and cobra venom factor (CoVF) to generate the CoVF-dependent C3 convertase which cleaves C3 (7) and activates the terminal complement components, C5-C9 (8). Fluid phase C3b, the major cleavage fragment of C3, interacts with factors B and D in a manner analogous to CoVF to form a fluid phase C3b-dependent C3 ...

Neuraminidase treatment of cells infected with herpes simplex virus type 1 (HSV-1) markedly enhanced the binding of complement component C3b to HSV 1 glycoprotein C (gC). When HSV-1 was grown in BHK RicR14 cells in which glycoproteins had reduced amounts of N-linked complex oligosaccharides, including sialic acid, the binding of C3b to gC was markedly enhanced. We used neuraminidase treatment t...

Previous theoretical studies of C3B have suggested that boron-doped graphite is a promising H2- and Li-storage material, with large maximum capacities. These characteristics could lead to exciting applications as a lightweight H2-storage material for automotive engines and as an anode in a new generation of batteries. However, for these applications to be realized a synthetic route to bulk C3B ...

Immunofluorescence studies showed that properdin (P) and factor B bind to C3-C3b receptor bearing human lymphoblastoid cells (Raji, Daudi) and B type human peripheral lymphocytes (HPL). P bound to Raji cells first incubated with normal human serum (NHS). EDTA, but not EGTA, halted the binding of P to cells incubated with NHS. However, fixation of P to Raji cells, after incubation with NHS first...

Local inflammation elicited by Neisseria gonorrhoeae correlates closely with sensitivity to killing by normal human serum. Serum-sensitive (SS) isolates are rendered resistant in vitro by lipooligosaccharide sialylation. Differences in C3b processing on N. gonorrhoeae in vitro were found to match findings at the cervical level in vivo. Nonsialylated SS gonococci bound 5-fold more C3b than did s...

We have used epifluorescence and photobleaching techniques to study the lateral distribution and motion of fluorescein-conjugated Fab fragments of anti-C3b receptor antibody bound to human neutrophils when the cells rest on various solid supports (microscope slides or cover slips). Supports composed of quartz, glass, or alkylated glass induced cellular adhesion, spreading, and an extensive late...

Vaccinia virus complement control protein (VCP) is a virulence determinant of vaccinia virus that helps protect the virus from the complement attack of the host. To characterize the interaction of VCP with C3 and C4 and understand the mechanism by which VCP inactivates complement, we have expressed VCP in a yeast expression system and compared the biologic activity of the purified protein to th...

The occurrence and distribution of distinct receptors for three C3 fragments on purified human blood lymphocytes were studied by rosette formation. Indicator cells were bovine, chicken, or sheep erythrocytes (E) bearing up to 100,000 molecules of human C3b (EC3b) without antibody. EC3b was converted to C3bi-bearing-E (EC3bi) with purified C3b inactivator (factor I) and beta1H (factor H), and to...

The complement receptor of the macrophage membrane recognizes particle-bound C3b but does not recognize particle-bound C3d. C3-b-coated sheep erythrocytes were bound to macrophages via their C3b receptors, and the preparations were then incubated with either latex particles or opsonized pneumococci (test particles). Macrophages ingested the test particles, but erythrocytes were not ingested; th...

The complement system in human blood is a major effector system in humoraVinnate immunity (1). Factor H is a 155kD glycoprotein which is involved in the regulation of the complement alternative pathway (2). Factor H regulates C3 turnover by 2 activities: decay acceleration activity describes the ability of factor H to bind to C3b thus displacing Bb from the active C3bBb enzyme (C3 convertase) o...