title: Macrophages largely contribute to heterologous anti-Propionibacterium acnes antibody-mediated protection from Actinobacillus pleuropneumoniae infection in mice.
abstract: Actinobacillus pleuropneumoniae is the causative agent of acute and chronic pleuropneumonia. Propionibacterium acnes is a facultative anaerobic gram-positive corynebacterium. We have previously found that anti-P. acnes antibodies can prevent A. pleuropneumoniae infections in mice. To investigate the role of macrophages in this process, affinity-purified anti-P. acnes IgG and anti-A. pleuropneumoniae IgG were used in opsonophagocytosis assays. Additionally, the efficacy of passive immunization with P. acnes serum against A. pleuropneumoniae was tested in macrophage-depleted mice. It was found that anti-P. acnes IgG had an effect similar to that of anti-A. pleuropneumoniae IgG (P > 0.05), which significantly promotes phagocytosis of A. pleuropneumoniae by macrophages (P < 0.01). It was also demonstrated that, after passive immunization with anti-P. acnes serum, macrophage-replete mice had the highest survival rate (90%), whereas the survival rate of macrophage-depleted mice was only 40% (P < 0.05). However, macrophage-depleted mice that had been passively immunized with naïve serum had the lowest survival rate (20%), this rate being lower than that of macrophage-replete mice that had been passively immunized with naïve serum. Overall, anti-P. acnes antibodies did not prevent A. pleuropneumoniae infection under conditions of macrophage depletion (P > 0.05). Furthermore, in mice that had been passively immunized with anti-P. acnes serum, macrophage depletion resulted in a greater A. pleuropneumoniae burden and more severe pathological features of pneumonia in lung tissues than occurred in macrophage-replete mice. It was concluded that macrophages are essential for the process by which anti-P. acnes antibody prevents A. pleuropneumoniae infection in mice.
authors: College of Veterinary Medicine, Jilin University, Changchun, China.
authors: Qiuyue
authors: Q
authors: Ma
authors: Changjiang
authors: C
authors: Sun
authors: Feng
authors: F
authors: Yang
authors: Lei
authors: L
authors: Wang
authors: Wanhai
authors: W
authors: Qin
authors: Xiaojing
authors: X
authors: Xia
authors: Xin
authors: X
authors: Feng
authors: Chongtao
authors: C
authors: Du
authors: Jingmin
authors: J
authors: Gu
authors: Wenyu
authors: W
authors: Han
authors: Liancheng
authors: L
authors: Lei
mesh_terms: D000189:Actinobacillus Infections / Q000276:immunology / Q000382:microbiology / Q000473:pathology / Q000662:veterinary*; D016977:Actinobacillus pleuropneumoniae / Q000276:immunology* / Q000502:physiology; D000818:Animals; D000907:Antibodies, Bacterial / Q000276:immunology*; D056738:Cross Protection; D004195:Disease Models, Animal; D005260:Female; D016908:Gram-Positive Bacterial Infections / Q000276:immunology / Q000382:microbiology / Q000473:pathology / Q000662:veterinary*; D007116:Immunization, Passive; D008264:Macrophages / Q000276:immunology*; D051379:Mice; D008807:Mice, Inbred BALB C; D010587:Phagocytosis; D011425:Propionibacterium acnes / Q000276:immunology* / Q000502:physiology; D013552:Swine; D013553:Swine Diseases / Q000276:immunology* / Q000382:microbiology / Q000473:pathology
chemical_list: D000907:Antibodies, Bacterial
keywords: anti-Propionibacterium acnes antibody; passive immunization