PT  - JOURNAL ARTICLE
AU  - Pamela L. Graney
AU  - Kristine Lai
AU  - Sarah Post
AU  - Ilana Brito
AU  - Jason Cyster
AU  - Ankur Singh
TI  - Organoid Polymer Functionality and Mode of &lt;em&gt;Klebsiella Pneumoniae&lt;/em&gt; Membrane Antigen Presentation Regulates Ex Vivo Germinal Center Epigenetics in Young and Aged B Cells
AID  - 10.1101/2020.02.16.947408
DP  - 2020 Jan 01
TA  - bioRxiv
PG  - 2020.02.16.947408
4099  - http://biorxiv.org/content/early/2020/02/17/2020.02.16.947408.short
4100  - http://biorxiv.org/content/early/2020/02/17/2020.02.16.947408.full
AB  - Antibiotic-resistant bacteria are a major global health threat that continues to rise due to a lack of effective vaccines. Of concern are Klebsiella pneumoniae that fail to induce in vivo germinal center B cell responses, which facilitate antibody production to fight infection. Immunotherapies using antibodies targeting antibiotic-resistant bacteria are emerging as promising alternatives, however, cannot be efficiently derived ex vivo, necessitating the need for immune technologies to develop therapeutics. Here, four-arm PEG-organoids were developed to elucidate the effects of polymer end-point chemistry, integrin ligands, and mode of K. pneumoniae antigen presentation on germinal center-like B cell epigenetics, to better define the cell-microenvironment factors regulating ex vivo germinal center dynamics. Notably, PEG vinyl sulfone or acrylate failed to sustain primary immune cells, but functionalization with maleimide (PEG-4MAL) led to B cell expansion and germinal center-like induction. RNA sequencing analysis of lymph node stromal and germinal center B cells showed niche associated heterogeneity of integrin-related genes. Incorporation of niche-mimicking bioadhesive peptides revealed that collagen 1 mimicking peptides promoted germinal center-like dynamics and epigenetics. PEG-4MAL organoids elucidated the impact of K. pneumoniae membrane embedded protein antigen versus soluble antigen presentation on germinal center-like activation and preserved the response across young and aged mice.