Every B cell and T cell in your body is born with a unique receptor. Not picked from a catalogue — built fresh by randomly stitching together gene fragments labeled V, D, and J, then sprinkling in random nucleotides at the seams. Trillions of possible outcomes per person. It's how your immune system is ready for pathogens it has never met.
This page picks one combination at random, like a slot machine. The colored letters are the resulting CDR3 — the part of the receptor that actually touches the antigen.
You don't, really. But longer CDR3s, exotic amino acids, and rare gene families score higher — same things that interest real immunologists, more or less. Pull the lever, see what falls out.
⌖ The IGH side uses ~50 human V genes, 12 D genes, 6 J genes.
⌖ The TRB side uses ~30 V genes, 2 D genes, 14 J genes.
⌖ Allele names follow IMGT nomenclature. The CDR3 fragments are illustrative, not bit-for-bit faithful to the germline.
⌖ N additions mimic terminal deoxynucleotidyl transferase. Junction trimming is, for now, the slot machine's secret.