Influence of Microbial Communities on Transplantation
1Surgery, University of Wisconsin School of Medicine and Public Health, Madison, WI, 2University of Wisconsin School of Medicine and Public Health, Madison, WI, 3Wisconsin Institute for Discovery, Madison, WI, 4Biomolecular Chemistry, University of Wisconsin-Madison, Madison, WI, 5Bacteriology, University of Wisconsin-Madison, Madison, WI
Meeting: 2020 American Transplant Congress
Abstract number: B-375
Keywords: Antigen presentation, Lymphocyte activation, Sensitization, T cells
Session Name: Poster Session B: Antigen Presentation / Allorecognition / Dendritic Cells
Session Type: Poster Session
Date: Saturday, May 30, 2020
Session Time: 3:15pm-4:00pm
Presentation Time: 3:30pm-4:00pm
*Purpose: A diverse microbiome is important in the generation, maintenance, and function of the immune system. Specific bacterial communities may have a relationship with organ rejection, infectious complications, and other clinical events. Understanding these relationships would prove valuable for prevention of complications, serve as biomarkers for high-risk patients, and may hold clues to establish tolerance. Utilization of a germ-free mouse model enables investigation of known microbial compositions to evaluate for differences in immune response.
*Methods: Splenocytes from male B6 12-14-week-old germ-free (GF), conventionalized (ConvD: colonized with a mixture of healthy human donors), or conventionally-raised (ConvR) mice were analyzed by flow cytometry for lymphocyte composition and mixed-lymphocyte reaction (MLR) for alloresponse. Potential human subjects for fecal microbial transfer to GF mice were identified by an internal kidney registry between ages 18-70, no prior other organ transplant, and no active infections. A stool sample was collected from patients who were highly-sensitized (CPRA>80), non-sensitized (CPRA<20), or post-kidney transplant +/- rejection). Bacterial composition will be identified by 16S rRNA sequencing and analyzed for differences in operational taxonomic units (OTUs). Samples will be selected for colonization of GF mice for transplant assays.
*Results: Preliminary lymphocyte analysis showed compared to ConvD mice, GF mice had a higher % B220 cells (70.5 +/- 0.7 vs 67.7 +/-.78, p=0.04) and % CD8 of T cells (43.8 +/-1 vs 40 +/-0.4, p=0.02), fewer CD4 of T cells ( 51.5 +/1.1 vs 55.6 +/- 0.46, p=0.03), and no significant difference in CD4 CD25 T cells (p=0.15), memory CD4 T cells (p=0.12), or memory CD8 T cells (p=0.06). Following a 5 day MLR, CD8 T cell proliferation by Ki-67 staining was greater in GF than ConvD mice (72% vs 60%, p<0.05.) however there was no significant difference of Ki-67 staining of CD4 T cells. Forty-five stool samples were collected from all subgroups and controls, and 16S sequencing data is forthcoming.
*Conclusions: Germ-free mice colonized with human stool provides a translational model to investigate the influence of microbial communities on transplant immunology. Preliminary studies show mice with a diverse healthy flora have an altered lymphocyte profile and a dampened alloresponse compared to germ-free controls. Future studies using samples selected by bacterial profile or clinical relevance to sensitization or rejection will inform the role of the microbiome in transplant immunology.
To cite this abstract in AMA style:Janek K, Fechner J, Krautkramer K, Sudakaran S, Denu J, Handelsman J, Rey F, Vivas E, Mezrich J. Influence of Microbial Communities on Transplantation [abstract]. Am J Transplant. 2020; 20 (suppl 3). https://atcmeetingabstracts.com/abstract/influence-of-microbial-communities-on-transplantation/. Accessed March 25, 2023.
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