---
title: ANARCI quickstart
description: Number an antibody sequence and read its CDRs with ANARCI in a few steps.
tags:
  - anarci
  - quickstart
---

You have an antibody variable-region sequence and you want it numbered — CDRs and framework regions carved out, germline genes named. [ANARCI](/docs/anarci) does it from sequence alone: paste the VH (and optionally VL), pick a numbering scheme, submit, and read the annotated regions off the result card, usually within a couple of minutes.

## Number a sequence

### Provide a sequence

Paste an antibody variable-region amino acid sequence — heavy, light, or both — or name a known therapeutic (for example `pembrolizumab`) and let the platform resolve the VH/VL from Thera-SAbDab. You can submit several sequences at once.

### Pick a numbering scheme

Keep the default `imgt` scheme for most work, or choose `kabat`, `chothia`, `aho`, or `wolfguy` if a downstream tool or convention expects it. Leave germline assignment on to have the closest V/J genes named.

### Submit and wait

ANARCI runs as an asynchronous CPU job on Modal. Submit it, and a result card appears on the canvas when the job finishes — typically within two to three minutes.

### Read the annotation

The card shows each chain's type, its numbered positions, the six CDR sequences and four framework regions, and the assigned germline genes. Use the CDR boundaries to target downstream engineering.

## In chat

Describe the antibody and the numbering you want — the model routes to ANARCI and chains onward when your prompt asks for more.

**Try this prompt** — [open in a guest chat](/chat/new?guest=true&prompt=Look%20up%20pembrolizumab%20in%20TheraSAbDab%2C%20annotate%20its%20heavy%20chain%20with%20IgBLAST%20for%20V%2FD%2FJ%20germline%20assignment%2C%20run%20ANARCI%20for%20CDR%20numbering%2C%20score%20joint%20VH%2FVL%20humanness%20with%20BioPhi%20and%20Humatch%20%E2%80%94%20which%20framework%20positions%20deviate%20most%20from%20germline%2C%20and%20is%20the%20humanness%20above%20the%2080%25%20therapeutic%20threshold%3F).

> Look up pembrolizumab in TheraSAbDab, annotate its heavy chain with IgBLAST for V/D/J germline assignment, run ANARCI for CDR numbering, score joint VH/VL humanness with BioPhi and Humatch — which framework positions deviate most from germline, and is the humanness above the 80% therapeutic threshold?

## What to do next

- **Humanize it** — feed the numbered sequence into [BioPhi](/docs/biophi) or score it with [Humatch](/docs/humatch).
- **Check manufacturability** — run [antibody developability](/docs/antibody-developability) on the candidate.
- **Get germline hits with statistics** — run [IgBLAST](/docs/igblast) for V(D)J alignment and hypermutation counts.

## Read next