Part:BBa_K4175000

anti-IL-6 scFv

Sequence and Features

Assembly Compatibility:

• 10
  INCOMPATIBLE WITH RFC[10]

  Illegal PstI site found at 604
  
• 12
  INCOMPATIBLE WITH RFC[12]

  Illegal PstI site found at 604
  
• 21
  INCOMPATIBLE WITH RFC[21]

  Illegal BglII site found at 512
  Illegal XhoI site found at 496
  
• 23
  INCOMPATIBLE WITH RFC[23]

  Illegal PstI site found at 604
  
• 25
  INCOMPATIBLE WITH RFC[25]

  Illegal PstI site found at 604
  Illegal AgeI site found at 556
  
• 1000
  COMPATIBLE WITH RFC[1000]

Biology

Anti-IL-6 single chain variable fragment (scFv) can bind to interleukin 6 (IL-6). It comprises of a variable heavy chain domain and a variable light chain domain, with a GSG linker joining the two domains. The variable heavy and light chain domain are derived from the human anti-IL-6 monoclonal antibody AME-19a (Tan et al., 2020).

Usage

Interleukin-6 (IL-6) is a pro-inflammatory cytokine that is pivotal to immune response, hematopoiesis, and acute-phase reactions. However, it is also a culprit for chronic inflammation and auto-immune diseases (Kaur et al., 2020). In the context of chimeric antigen receptor-T (CAR-T) therapy, IL-6 is found to mediate cytokine release syndrome (CRS), a concerning side effect of CAR-T therapy which could lead to multi-organ failure in the worst case (Leclercq et al., 2022).

To ameliorate the symptoms of CRS (e.g., fever, hypotension, respiratory deficiency), Tan et al. designed a membrane-bound form of IL-6 receptor (mbaIL6). They added anti-IL-6 scFv shown herein to the CD8α hinge and transmembrane domain. mbaIL6 was cloned into pMSCV-IRES-GFP plasmid together with anti–CD19-41BB-CD3ζ construct, and the plasmid was expressed in T cells (Tan et al., 2020). They found that when mbaIL6 and anti-CD19 CAR were simultaneously expressed (dual-expressed) in T cells, IL-6 derived from monocyte cell lines (THP-1) was effectively neutralized (Fig 1). This is likely to due to the capture of IL-6 by mbaIL6. Meanwhile, the cytotoxic effect of CAR-T cells was not affected (Fig 2).

As in immunodeficiency mice injected with leukemic cells (Nalm-6 cells), mbaIL6-expressing CAR-T cells without IL-6 neutralizing effect (Fig 3) (Tan et al., 2020).

For our usage, we intend to take advantage of anti-IL-6 scFv to design a negative feedback loop for CAR-T cell. We joined anti-IL-6 scFv with Notch core domain (BBa_K4175001) and ZF_GAl4_KRAB (BBa_K2446037) and expressed this device in CAR-T cells (IL-6_scfv-Notch-Gal4KRAB). We hoped that this device would inhibit the expression of CAR when IL-6 concentration reaches a deteriorating high level during CRS. For more detailed information, please see BBa_K4175008.