Search bioRxiv⌕ Search

bioRxiv · 10.1101/262519

Cryopreservation of human mucosal tissues

Abstract

BACKGROUNDCryopreservation of leukocytes isolated from the cervicovaginal and colorectal mucosa is useful for the study of cellular immunity (see Hughes SM et al. PLOS ONE 2016). However, some questions about mucosal biology and sexually transmitted infections are better addressed with intact mucosal tissue, for which there is no standard cryopreservation protocol.\n\nMETHODS AND FINDINGSTo find an optimal preservation protocol for mucosal tissues, we tested slow cooling (1%C/min) with 10% dimethylsulfoxide (designated \"cryopreservation\") and fast cooling (plunge in liquid nitrogen) with 20% dimethylsulfoxide and 20% ethylene glycol (\"vitrification\"). We compared fresh and preserved human cervicovaginal and colorectal tissues in a range of assays, including metabolic activity, human immunodeficiency virus infection, cell phenotype, tissue structure by hematoxylin-and-eosin staining, cell number and viability, production of cytokines, and microbicide drug concentrations. Metabolic activity, HIV infectability, and tissue structure were similar in cryopreserved and vitrified vaginal tissues. However, vitrification led to poor cell recovery from the colorectal mucosa, with 90% fewer cells recovered after isolation from vitrified colorectal tissues than from cryopreserved. HIV infection rates were similar for fresh and cryopreserved ectocervical tissues, whereas cryopreserved colorectal tissues were less easily infected than fresh tissues (hazard ratio 0.7 [95% confidence interval 0.4, 1.2]). Finally, we compared isolation of cells before and after cryopreservation. Cell recoveries were higher when cells were isolated after freezing and thawing (71% [59-84%]) than before (50% [38-62%]). Cellular function was similar to fresh tissue in both cases. Microbicide drug concentrations were lower in cryopreserved explants compared to fresh ones.\n\nCONCLUSIONSCryopreservation of intact cervicovaginal and colorectal tissues with dimethylsulfoxide works well in a range of assays, while the utility of vitrification is more limited. Cell yields are higher from cryopreserved intact tissue pieces than from thawed cryopreserved single cell suspensions isolated before freezing, but T cell functions are similar.

Source connections

Explore related subjects

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

Hughes, S. M., Ferre, A. L., Yandura, S. E., Shetler, C., Baker, C. A. R., Calienes, F., Levy, C. N., Astronomo, R. D., Shu, Z., Lentz, G. M., Fialkow, M., Kirby, A. C., McElrath, M. J., Sinclair, E., Rohan, L. C., Anderson, P. L., Shacklett, B. L., Dezzutti, C. S., Gao, D., Hladik, F.. 2018-03-14. Cryopreservation of human mucosal tissues. https://doi.org/10.1101/262519

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related preprints

CD19-CAR T-cell therapy resets the EBV+ autoreactive B cell repertoire in autoimmune disease

Epstein-Barr virus (EBV) reprograms autoreactive B cells into activated antigen-presenting cells that drive pathogenic T- and B-cell responses in autoimmune disease. Using EBV B-cell sequencing (EBV-seq), we profiled EBV+ B cells in patients treated with CD19 chimeric antigen receptor (CAR) T cells (systemic lupus, n=6; idiopathic inflammatory myopathies, n=3; systemic sclerosis, n=3) or rituximab (n=15). CAR T cells, but not rituximab, depleted EBV+ B cells, resetting the repertoire toward a naive state: predominantly IgM+ with minimal somatic hypermutation. Post-rituximab B-cells remained class-switched, hypermutated, and activated. Monoclonal antibodies cloned from EBV+ B cells lost autoreactivity after CAR T cells but not rituximab. Sustained drug-free remission occurred in 8/12 CAR-treated but 0/15 rituximab-treated patients. EBV+ B cells were predominantly Latency III and resisted anti-CD20 and anti-CD19 antibodies, yet were killed by CAR T cells and T-cell engagers. CD19-CAR T-cell therapy resets the autoreactive EBV+ B-cell repertoire, which may underlie sustained drug-free remission.

immunology↗

A minimal two-residue C-terminal truncation of AID in adult-onset hyper-IgM syndrome type 2 (HIGM2)

Activation-induced cytidine deaminase (AID), encoded by AICDA, facilitates class-switch recombination (CSR) and somatic hypermutation (SHM) in activated B cells. Loss of AID function causes hyper-IgM syndrome type 2 (HIGM2). While typically autosomal recessive, three C-terminal truncation variants have been reported to act in autosomal dominant manner. We describe a novel heterozygous AICDA nonsense variant, c.589G>T (p.G197*), that truncates the final two C-terminal residues of AID and results in adult-onset HIGM2. Single-cell sequencing of primary patient B cells revealed a complete block in CSR and a [~]10-fold reduction in SHM. AICDA mRNA expression was balanced between wild-type and variant alleles, yet AID protein abundance was reduced to [~]56% with normal subcellular localization. Remarkably, inducible germinal center (iGB) cultures restored CSR in purified naive patient B cells. CRISPR-Cas9 editing of healthy donor B cells confirmed that the iGB platform can rescue B cells harboring heterozygous, but not homozygous, AICDA variants. These results demonstrate that even a two-amino-acid truncation at the AID C-terminus is sufficient to disrupt its function and cause HIGM2.

immunology↗

Defining the Functional Consequence of the Human Ocular Microbiome

The ocular surface is one of the body's most environmentally exposed mucosal barriers, yet it is considered low biomass and harbors orders of magnitude fewer bacteria than microbe-rich sites like the gut. This has cast doubt on whether a functional core ocular microbiome exists at all. Having previously defined a protective gd T cell and IL-17 axis engaged by the murine commensal Corynebacterium mastitidis, we asked whether human-derived bacteria could do the same. Pairing sequencing and culturomics of healthy human conjunctiva from two geographically distinct cohorts, we define a stable core microbiome and identify Corynebacterium bovis as a consistent eye-resident commensal rather than a transient contaminant. In humans, C. bovis elicits a non-pathogenic response marked by IL-17 secretion by {gamma}{delta} T cells and circulating C. bovis-specific IgG, which suggests commensalism rather than pathology. Colonizing mice with human C. bovis strains from Pittsburgh or Miami reproduced this program and conferred protection against ocular infection with Staphylococcus aureus. Together, these findings identify C. bovis as a human-derived ocular commensal that can drive protective {gamma}{delta} T cell immunity, translating a mechanism previously defined only in mice into human relevance and a rational target against sight-threatening infection.

immunology↗