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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: BACKGROUND, METHODS, RESULTS. Meshes: Animal Structures, Animals, Antibodies, Bacterial, Antibodies, Neutralizing, Antigens, Bacterial, Bacterial Load, Bacterial Proteins, Bacterial Vaccines, CD4-Positive T-Lymphocytes, CD8-Positive T-Lymphocytes, Cell Proliferation, Cytokines, Disease Models, Animal, Male, Membrane Proteins, Mice, Mice, Inbred C3H, Recombinant Proteins, Rickettsia, Rickettsia Infections, Th1 Cells, Vaccines, Subunit, Vaccines, Synthetic.
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Does recombinant protein YbgF induce protective immunity against Rickettsia heilongjiangensis infection in C3H/HeN mice? Context: Surface proteins YbgF and PrsA are major seroreactive antigens of Rickettsia heilongjiangensis, the etiological agent of Far-Eastern spotted fever. This study investigated their potential immunogenicity for protective immunity. Recombinant YbgF and PrsA were used to immunize C3H/HeN mice and rickettsial loads in immunized mouse organs were assessed after R. heilongjiangensis challenge. Anti-sera from immunized mice were applied to neutralize rickettsiae. CD4⁺ and CD8⁺ T cells isolated from R. heilongjiangensis-infected mice were stimulated with YbgF or PrsA, and proliferation and cytokine production assessed. The IgG2a/IgG1 ratio of sera was markedly increased in YbgF-immunized mice but was unaltered in PrsA-immunized mice after immunization. The rickettsial load in YbgF-immunized mice was significantly lower than in PrsA-immunized mice after R. heilongjiangensis challenge. Incubation with anti-serum to YbgF, but not PrsA, significantly reduced the number of rickettsiae adhering to and invading endothelial cells. The proliferation level and tumor necrosis factor-α secretion level of CD4⁺ T cells from R. heilongjiangensis-infected mice were significantly higher than in uninfected mice after stimulation with YbgF but not PrsA.
assistant
YbgF is a novel protective antigen that induces a Th1-type of protective immune response against R. heilongjiangensis infection. Final Decision: yes