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Medical AI Inquiry: You was designed to assist in medical decision-making based on the provided user questions. It is crucial to provide accurate and comprehensive information to receive a well-informed response.  Labels: OBJECTIVE, METHODS, RESULTS. Meshes: Animals, Blotting, Western, Cell Line, Tumor, Chemotaxis, Dose-Response Relationship, Drug, Doxycycline, HEK293 Cells, Humans, Macrophages, Phagocytosis, Rats, Receptors, IgG, Reverse Transcriptase Polymerase Chain Reaction, Up-Regulation.
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Does [ Up-regulated expression of FcγRIIB inhibit phagocytosis and chemotaxis of macrophages ]? Context: To construct an inducible lentivirus vector of FcγRIIB and observe its effect on rat macrophages. FcγRIIB gene fragment was obtained from rat liver mRNA as the template by reverse transcription PCR, and then cloned into tetracycline response element (TRE) plasmid to establish recombinant plasmid TRE-FcγRIIB. Lentiviral packaging plasmid was transfected into HEK293T cells together with the recombinant plasmid TRE-FcγRIIB and Tet plasmid, respectively. Then the titers of the above lentiviruses were measured. Rat macrophages were co-infected by FcγRIIB-lentivirus and Tet-lentivirus, thereafter induced by doxycycline (DOX) of gradient concentrations. The mRNA and protein levels of FcγRIIB were measured by immunofluorescence, real-time quantitative PCR (qRT-PCR) and Western blotting. After induced by DOX, macrophages were detected in phagocytic and chemotactic function. The recombinant plasmid we constructed was confirmed correct by PCR, enzyme digestion and sequencing. The titers of FcγRIIB-lentivirus and Tet-lentivirus reached 10(6) TU/mL. FcγRIIB was expressed under DOX induction in macrophages which were co-infected by the packaged lentiviruses. In addition, FcγRIIB level was positively correlated with the concentration of DOX, but was negatively correlated with phagocytosis and chemotaxis of macrophages.
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The up-regulation of FcγRIIB expression in macrophages might suppress cell phagocytosis and chemotaxis. Final Decision: yes