Antibody format schematics

Describe an antibody format in one line. Get a publication-ready figure.

AbDraw reads AbML — a compact text notation for antibody architecture — and draws the molecule as a domain schematic you can drop straight into a paper or a deck. 43 formats ship in the library, from a bare Fv to trispecific knob-into-hole constructs. Everything exports as vector SVG.

Open the tool Browse all 43 formats Source on GitHub
CrossMab CH1-CLAbML: VH.a(1:6)-CH1(2:7){1}-H(3:10){2}-CH2(4:11)-CH3>(5:12)|VL.a(6:1)-CL(7:2){1}|VH.b(8:13)-CL(9:14){1}-H(10:3){2}-CH2(11:4)-CH3@(12:5)|VL.b(13:8)-CH1(14:9){1}CH2CH2CH3CH3CH1CLVHVLCLCH1VHVL
Why

Built for the formats that are hard to draw

Drawing an IgG is easy. Drawing a CrossMab so a reader can see which domains crossed is not — and that is exactly the figure a bispecific paper needs.

Colour follows the domain

When VH/VL or CH1/CL swap chains, the colour travels with the domain rather than the chain. A CrossMab panel reads correctly without a caption.

Text in, figure out

One line of AbML is a complete, diffable, version-controllable description of a construct. Paste it in a protocol; regenerate the figure any time.

Real vector output

SVG with live text and shapes, not a raster trace. Opens editable in Illustrator, Inkscape, Affinity and PowerPoint.

Panel figures

Stack several formats into a lettered A/B/C grid and export the whole comparison as one SVG.

Library

A starting point for every common architecture

Eight families, 43 formats. Each one opens in the editor so you can modify it rather than start from a blank canvas.

FragmentsCanonicalAsymmetric bispecific IgGAppended IgGFragment bispecificsFc fusionsTrispecificReceptors
CrossMab CH1-CLAbML: VH.a(1:6)-CH1(2:7){1}-H(3:10){2}-CH2(4:11)-CH3>(5:12)|VL.a(6:1)-CL(7:2){1}|VH.b(8:13)-CL(9:14){1}-H(10:3){2}-CH2(11:4)-CH3@(12:5)|VL.b(13:8)-CH1(14:9){1}CH2CH2CH3CH3CH1CLVHVLCLCH1VHVL
CrossMab CH1-CL CH1 and CL are exchanged in one arm, so the wrong light chain can no longer pair. Open in tool →
Knob-into-holeAbML: VH.a(1:6)-CH1(2:7){1}-H(3:10){2}-CH2(4:11)-CH3>(5:12)|VL.a(6:1)-CL(7:2){1}|VH.b(8:13)-CH1(9:14){1}-H(10:3){2}-CH2(11:4)-CH3@(12:5)|VL.b(13:8)-CL(14:9){1}CH2CH2CH3CH3CH1CLVHVLCH1CLVHVL
Knob-into-hole Reciprocal CH3 steric mutations drive heterodimerisation of two different heavy chains. Open in tool →
DVD-IgAbML: VH.b(1:8)-L(2)[LENGTH:6]-VH.a(3:10)-CH1(4:11){1}-H(5:16){2}-CH2(6:17)-CH3(7:18)|VL.b(8:1)-L(9)[LENGTH:6]-VL.a(10:3)-CL(11:4){1}|VH.b(12:19)-L(13)[LENGTH:6]-VH.a(14:21)-CH1(15:22){1}-H(16:5){2}-CH2(17:6)-CH3(18:7)|VL.b(19:12)-L(20)[LENGTH:6]-VL.a(21:14)-CL(22:15){1}CH2CH2CH3CH3CH1CLVHVLVHVLCH1CLVHVLVHVL6666
DVD-Ig A second variable domain stacked N-terminal to each native one: tetravalent and bispecific. Open in tool →
BiTE (tandem scFv)AbML: VH.a(1:3)-L(2)[LENGTH:15]-VL.a(3:1)-L(4)[LENGTH:5]-VH.b(5:7)-L(6)[LENGTH:15]-VL.b(7:5)VHVLVHVL15515
BiTE (tandem scFv) Two scFvs in tandem on one chain — the T-cell engager archetype, no Fc at all. Open in tool →
Bispecific VHH-FcAbML: VHH.a(1)-H(2:6){2}-CH2(3:7)-CH3>(4:8)|VHH.b(5)-H(6:2){2}-CH2(7:3)-CH3@(8:4)CH2CH2CH3CH3VHHVHH
Bispecific VHH-Fc Two different VHH domains on a knob-into-hole Fc — the compact asymmetric bispecific. Open in tool →
DARTAbML: VH.a(1:7)-L(2)[LENGTH:5]-VL.b(3:5)-H*(4:8){1}[MOD:DISULFIDE]|VH.b(5:3)-L(6)[LENGTH:5]-VL.a(7:1)-H*(8:4){1}[MOD:DISULFIDE]VHVLVLVH55
DART A diabody locked by an added C-terminal interchain disulfide for stability. Open in tool →
FabAbML: VH.a(1:3)-CH1(2:4){1}|VL.a(3:1)-CL(4:2){1}VHVLCH1CL
Fab Heavy-chain Fd (VH–CH1) disulfide-bonded to a complete light chain. Open in tool →
Trispecific IgG-scFvAbML: VH.a(1:10)-CH1(2:11){1}-H(3:14){2}-CH2(4:15)-CH3>(5:16)-L(6)[LENGTH:15]-VH.c(7:9)-L(8)[LENGTH:15]-VL.c(9:7)|VL.a(10:1)-CL(11:2){1}|VH.b(12:17)-CH1(13:18){1}-H(14:3){2}-CH2(15:4)-CH3@(16:5)|VL.b(17:12)-CL(18:13){1}CH2CH2CH3CH3VHVLCH1CLVHVLCH1CLVHVL1515
Trispecific IgG-scFv A knob-into-hole bispecific with a third specificity appended as an scFv on one chain. Open in tool →
See all 43 →
Notation

AbML in a minute

A molecule is a list of chains separated by |. Each chain is a list of domains separated by -, written N-terminus to C-terminus. That alone draws a picture:

VH.a-CH1-H-CH2-CH3 | VL.a-CL

Add identifiers in parentheses to say which domains pair, a number in braces for the disulfides between them, and modification symbols for engineered interfaces. A knob-into-hole heavy chain:

VH.a(1:6)-CH1(2:7){1}-H(3:10){2}-CH2(4:11)-CH3>(5:12)
.a – .hspecificity — decides the colour of the arm
(3:10)this domain is number 3 and pairs with number 10
{2}two disulfides across that pairing
> @knob and hole
+ _charge pair
^ ! *conjugation site, aglycosyl CH2, general modification
[ANTI:CD3]comments — also MOD, TYPE, LENGTH, CLASS, NOTE

The tool carries the same reference under its Syntax tab, and the full grammar is in docs/abml.md.

Use it

Three ways to run it

In the browser

Nothing to install. Open the tool and start typing; every format is deep-linkable, e.g. app/#crossmab-ch1-cl.

One file, offline

Download app/index.html and open it locally. No build step, no network, no dependencies.

As data

formats.json carries every format as a name, category, description and AbML string, for scripting your own pipelines.