> ## Documentation Index
> Fetch the complete documentation index at: https://docs.adaptyvbio.com/llms.txt
> Use this file to discover all available pages before exploring further.

# VHH (Nanobodies)

> Single-domain antibody fragment derived from camelids

VHH fragments (nanobodies) are the smallest natural antigen-binding domains, derived from camelid heavy-chain-only antibodies.

<CardGroup cols={2}>
  <Card title="Size" icon="ruler">
    \~15 kDa (smallest)
  </Card>

  <Card title="Origin" icon="horse-head">
    Camelids (llamas, camels)
  </Card>

  <Card title="Stability" icon="shield">
    Exceptional heat/pH resistance
  </Card>

  <Card title="Format" icon="atom">
    Single domain, no light chain
  </Card>
</CardGroup>

## Unique Features

<Tip>
  VHH can access cryptic epitopes in protein cavities that larger antibodies cannot reach.
</Tip>

* **Extended CDR3 loops** - Longer than conventional antibodies
* **No light chain pairing** - Functions independently
* **Refolding capability** - Can refold after denaturation

<Warning>
  Requires specialized discovery platforms (camelid immunization or synthetic libraries).
</Warning>

## Applications

<AccordionGroup>
  <Accordion title="Therapeutics">
    Excellent tissue penetration and low immunogenicity make VHH ideal for in vivo applications.
  </Accordion>

  <Accordion title="Intracellular Research">
    Can be expressed inside cells for intracellular target studies.
  </Accordion>

  <Accordion title="Diagnostics">
    Stable under harsh conditions, ideal for robust assays.
  </Accordion>
</AccordionGroup>