{
  "id": 4691131,
  "title": "Site Specific Fluorescent Labeling via SpyTag SpyCatcher for Rapid Hybridoma Screening in Semi-Solid Medium",
  "url": "https://urgent.news/2026/08/31/site-specific-fluorescent-labeling-via-spytag-spycatcher-for-rapid",
  "topic": "science",
  "section": "Science",
  "published": "2026-08-31T00:00:00.000Z",
  "source": {
    "name": "bioRxiv",
    "slug": "biorxiv",
    "url": "https://www.biorxiv.org/content/10.64898/2026.08.21.746134v1?rss=1"
  },
  "original_language": "en",
  "account": "Conventional hybridoma screening in semi-solid medium relies on antigens tagged with visible fluorophores, such as FITC or AF488, to quickly recognize antibody-producing cell lines. Regrettably, traditional chemical bonding methods involving NHS-esters or isothiocyanate groups often alter lysine residues within the targeted epitopes, potentially disrupting antibody recognition of these vital areas.\n\nIn this report, researchers detail a SpyTag SpyCatcher-based site-specific labeling approach that avoids antigen modification during screening. The innovative technique involves genetically attaching a 16-amino-acid SpyTag to the C-terminus of the target antigen, facilitating covalent linking to an sfGFP SpyCatcher fluorescent probe. When placed in semi-solid medium alongside both the SpyTag-antigen and sfGFPSpyCatcher, positive hybridoma clones become easily identifiable through unique fluorescent halos. Conversely, negative clones do not exhibit any detectable signal.\n\nRemarkably, the site-specific methodology resulted in a substantially higher proportion of fluorescence-positive clones compared to the conventional AF488-labeled antigen technique. This implies that preserving the epitope structure contributes to improved screening recovery rates. Importantly, the site-specific approach did not negatively impact hybridoma growth or final clone positivity, presenting a straightforward, speedy, and epitope-friendly method for monoclonal antibody screening within semi-solid medium.",
  "summary": "Hybridoma screening in semi-solid medium typically employs antigens labeled with visible fluorophores (e.g., FITC, AF488) to enable single-step identification of antibody-secreting clones. However, conventional chemical conjugation via NHS-esters or isothiocyanate groups frequently modifies lysine residues located within epitopes, potentially abrogating antibody recognition of these critical…",
  "key_points": [],
  "editors_take": null,
  "illustration": null,
  "coverage": {
    "outlets": 1,
    "also_reported_by": []
  },
  "ai_generated": true,
  "disclaimer": "Summaries, key points and the editor’s take are written by software from other outlets’ reporting and may contain errors — always check the linked original."
}