A Pathogenic Role for FcγRI in the Immune Response against Chlamydial Respiratory Infection

FcγRI is an important cell surface receptor reported to be involved in multiple immune responses, although it has not yet been extensively studied in intracellular bacterial infections. Here, using a mouse model of C. muridarum respiratory infection, we were able to determine how FcγRI regulates the host resistance against chlamydial invasion. According to our findings, the chlamydial loads and pulmonary pathology were both reduced in FcγRI deficient (Fcgr1−/−) animals. Being infected, monocytes, macrophages, neutrophils, DCs, CD4+/CD8+ T cells, and effector Th1 subsets displayed increased FcγRI expression patterns. Altered infiltration of these cells in the lungs of Fcgr1−/− mice further demonstrated the regulation of FcγRI in the immune system and identified Th1 cells and macrophages as its target cell populations. As expected, we observed that the Th1 response was augmented in Fcgr1−/− mice, while the pro-inflammatory M1 macrophage polarization was constrained. These findings might indicate FcγRI as a potential regulator for host immunity and inflammatory response during chlamydial infection

Synthesis, Crystal Structure, Stacking Effect and Antibacterial Studies of a Novel Quaternary Copper (II) Complex with Quinolone

The structural properties of a new copper (II) complex [Cu2(cip)2(bpy)2(pip)]·6H2O (bpy=2,2’-bipyridyl, cip=1-cyclopropyl-6-4-oxo-1,4-dihydroquinoline-3-carboxylic acid, pip= piperazinyl anion), obtained during the synthesis of the copper complex with ciprofloxacin (cpf), has been investigated. The complex crystallizes in the triclinic system, space group P-1. The cell dimensions are: a=6.874(2) Å, b= 10.761(3) Å, c= 17.969(5) Å, α =80.071(6)°, β= 85.253(6)°, γ=79.109(6)°，V=1284.5(6) Å3, and Z=2. The Cu (II) ion displays a five-coordinate square pyramidal coordination with two nitrogen donors from bpy, the 4-keto and 3-carboxylate oxygen donors of cip, and the third nitrogen atom of the pip anion occupying the fifth site. There is a stack effect between cip ring and bpy ring from another molecule, where the stacking distance is about 3.5 Å. The results of elemental analysis and FT-IR measurement are also included. Both ligand and complex were assayed against gram-positive and gram-negative bacteria by the doubling dilutions method. The complex shows the same minimal inhibitory concentration (MIC) against S. Aureus and E. Coli bacteria as the corresponding ligand