hitlist 1.9.0

Curated mass spectrometry evidence for MHC ligand data from IEDB and CEDAR

hitlist

A curated, harmonized, ML-training-ready MHC ligand mass-spectrometry dataset.

hitlist ingests immunopeptidome data from IEDB, CEDAR, and paper supplementary tables (PRIDE/jPOSTrepo); filters out binding-assay data; joins every observation to expert-curated sample metadata (HLA genotype, tissue, disease, perturbation, instrument); and ships it as a single parquet file + pandas-friendly Python API.

What's curated

	Count
Curated PMIDs (pmid_overrides.yaml)	155 — covers 89.5% of observations
ms_samples entries with per-sample metadata	359
ms_samples entries with 4-digit HLA typing	237
Supplementary CSVs ingested (PRIDE/jPOSTrepo)	5 (JY, HeLa, SK-MEL-37, Raji, plasma — Gomez-Zepeda 2024)
Species reference proteomes (registry)	19 (Ensembl: 4, UniProt: 15)
Viral reference proteomes (registry)	30 distinct viruses, 54 name aliases

What's in the observations table

After hitlist data build (v1.4.4):

Total observations (MS-eluted, all species)	4,053,693
Unique peptides	1,285,987
Unique MHC alleles	691
MHC species covered	21
IEDB rows	3,986,991
CEDAR rows	595
Supplementary rows	66,107

Human MHC-I breakdown

Observations	2,672,046
Unique peptides	748,386
Mono-allelic (exact allele)	579,096 obs / 300K peptides / 119 alleles
Multi-allelic with allele match	450,399 obs
Multi-allelic with class-pool (N of M alleles)	784,370 obs
Allele-resolved sample_mhc coverage	74.8%

Install

pip install hitlist

Quick start for ML training

# One-time: register IEDB + CEDAR downloads and build
hitlist data register iedb /path/to/mhc_ligand_full.csv
hitlist data register cedar /path/to/cedar-mhc-ligand-full.csv
hitlist data build                           # ~90s, writes ~/.hitlist/observations.parquet

# Export training-ready CSVs
hitlist export observations --class I --species "Homo sapiens" --mono-allelic \
    --min-allele-resolution four_digit -o mono_allelic_classI.csv

hitlist export observations --class II --species "Homo sapiens" \
    -o multi_allelic_classII.csv

Binding-assay data (peptide microarrays, refolding, MEDi display) is excluded at build time — the observations table contains only MS-eluted immunopeptidome data.

Python API

Training-data export

from hitlist.export import generate_observations_table

# Mono-allelic human class I: 579K observations with ground-truth allele
mono = generate_observations_table(
    mhc_class="I",
    species="Homo sapiens",
    is_mono_allelic=True,
    min_allele_resolution="four_digit",
)

# Multi-allelic with at least allele-pool info (74.8% of all rows)
multi = generate_observations_table(mhc_class="I", species="Homo sapiens")
multi_with_alleles = multi[multi["sample_mhc"].str.strip() != ""]

Species filters accept any variant — "Homo sapiens", "human", "homo_sapiens", "Homo sapiens (human)" all work.

Raw observations loading

from hitlist.observations import load_observations, is_built, observations_path

df = load_observations()                       # everything (MS-eluted only)
df = load_observations(mhc_class="I")          # class I only
df = load_observations(species="Homo sapiens") # human only
df = load_observations(source="iedb")          # filter by source
df = load_observations(columns=["peptide", "mhc_restriction", "src_cancer"])

Building / curation

from hitlist.builder import build_observations
from hitlist.curation import (
    classify_ms_row,
    normalize_species,
    normalize_allele,
    load_pmid_overrides,
)
from hitlist.supplement import scan_supplementary, load_supplementary_manifest

build_observations(with_flanking=True, use_uniprot_search=True, force=False)
normalize_species("human")           # → "Homo sapiens"
normalize_allele("H-2Kb")            # → "H2-K*b"
scan_supplementary()                 # DataFrame of curated paper-supplement peptides

Peptide → protein attribution and flanking context

hitlist data build always produces two parquet files (use --no-mappings to skip):

• ~/.hitlist/observations.parquet — one row per assay observation
• ~/.hitlist/peptide_mappings.parquet — one row per (peptide, protein, position)

The mappings sidecar preserves multi-mapping so a peptide shared by MAGEA1/A4/A10/A12 keeps every paralog. Observations additionally carry semicolon-joined identity columns:

column	example
gene_names	MAGEA4;MAGEA10
gene_ids	ENSG00000147381;ENSG00000124260
protein_ids	P43359;P43363
n_source_proteins	2

from hitlist.observations import load_observations
from hitlist.mappings import load_peptide_mappings

# Central columns — fast for everyday filters (uses mappings sidecar for pushdown)
df = load_observations(gene_name="PRAME")

# Long form for paralog / position / flank analysis
mappings = load_peptide_mappings(gene_name="MAGEA4")
# columns: peptide, protein_id, gene_name, gene_id, position, n_flank, c_flank, proteome

For ad-hoc queries without building the full table:

from hitlist.proteome import ProteomeIndex

idx = ProteomeIndex.from_ensembl(release=112, species="human")
flanking = idx.map_peptides(["SLLMWITQC", "GILGFVFTL"], flank=10)

Proteome registry / UniProt resolution

from hitlist.downloads import (
    lookup_proteome,           # org string → registry entry (dict)
    fetch_species_proteome,    # download FASTA and cache to ~/.hitlist/proteomes/
    resolve_proteome_via_uniprot,  # direct UniProt REST lookup
    list_proteomes,            # manifest section
)

lookup_proteome("Mycobacterium tuberculosis", use_uniprot=True)
# → {'kind': 'uniprot', 'proteome_id': 'UP000001020', ...}

Output schema — generate_observations_table()

Column	Meaning
peptide	Amino acid sequence
mhc_restriction	Allele from IEDB (may be "HLA class I" for multi-allelic studies)
sample_mhc	Allele(s) known for the source sample — the useful field for training
mhc_class	I, II, or non classical
mhc_species	Canonical species (normalized via mhcgnomes)
is_monoallelic	True if sample has a single transfected allele (721.221, C1R, K562, MAPTAC…)
has_peptide_level_allele	True if mhc_restriction is a specific allele (not "HLA class I")
is_potential_contaminant	True for MS-eluted peptides that failed NetMHCpan binding prediction
sample_match_type	How sample_mhc was populated (see below)
matched_sample_count	Number of curated samples for this PMID
src_cancer, src_healthy_tissue, src_ebv_lcl, ...	Mutually-exclusive biological source categories
source	iedb, cedar, or supplement
source_organism, reference_title, cell_name, source_tissue, disease	IEDB sample context
instrument, instrument_type, acquisition_mode, fragmentation, labeling, ip_antibody	MS acquisition from ms_samples curation
gene_names, gene_ids, protein_ids, n_source_proteins	Multi-mapping peptide → source-protein attribution (always populated; use peptide_mappings.parquet for long-form positions + flanks)

sample_match_type — join provenance

Value	Meaning	Training-grade?
allele_match	IEDB recorded a specific allele and it matched a curated sample genotype	Yes — high confidence
single_sample_fallback	IEDB class-only but study has exactly 1 sample, so sample_mhc = that sample's full genotype	Yes (for deconvolution)
pmid_class_pool	IEDB class-only + multiple samples — sample_mhc = union of all class-matching alleles across samples	Yes (for deconvolution), lower precision
unmatched	No curated sample for this PMID, or all samples have mhc: unknown	No — sample_mhc empty

Biological source classification

Every observation is classified by mutually-exclusive biological source category:

Category	Flag	Rule
Cancer	src_cancer	Tumor tissue, cancer patient biofluids, or non-EBV cell lines
Adjacent to tumor	src_adjacent_to_tumor	Surgically resected "normal" tissue (per-PMID override)
Activated APC	src_activated_apc	Monocyte-derived DCs/macrophages with pharmacological activation
Healthy somatic	src_healthy_tissue	Direct ex vivo, healthy donor, non-reproductive, non-thymic
Healthy thymus	src_healthy_thymus	Direct ex vivo thymus (expected for CTAs, AIRE-mediated)
Healthy reproductive	src_healthy_reproductive	Direct ex vivo testis, ovary (expected for CTAs)
EBV-LCL	src_ebv_lcl	EBV-transformed B-cell lines
Cell line	src_cell_line	Any cultured cell line

Cancer-specific = src_cancer AND NOT src_healthy_tissue. Thymus, reproductive tissue, adjacent tissue, EBV-LCLs, and activated APCs do NOT disqualify a peptide from being cancer-specific.

CLI reference

Data management

hitlist data register <name> <path> [-d DESCRIPTION]    # register a local file
hitlist data fetch <name> [--force]                     # download a known dataset (IEDB/CEDAR/viral FASTAs)
hitlist data refresh <name>                             # re-download
hitlist data info <name>                                # detailed metadata (JSON)
hitlist data path <name>                                # print the registered path
hitlist data remove <name> [--delete]                   # unregister (optionally delete file)
hitlist data list                                       # show registered datasets
hitlist data available                                  # show all known datasets

Build the observations table

hitlist data build [--force]                            # ~90s full scan with tqdm progress
hitlist data build                                      # always builds peptide_mappings.parquet
hitlist data build --use-uniprot                        # broader proteome coverage via UniProt REST
hitlist data build --no-mappings                        # skip mapping step (faster, no gene attribution)
hitlist data build --no-fetch-proteomes                 # don't auto-download missing proteomes
hitlist data build --proteome-release 112               # Ensembl release for human/mouse/rat

Proteome management

hitlist data fetch-proteomes [--min-observations N] [--use-uniprot] [--force]
hitlist data list-proteomes

Index (for raw peptide counts)

hitlist data index [--source iedb|cedar|merged|all] [--force]

Export

hitlist export observations [filters...] -o train.csv   # MS immunopeptidome + sample metadata
hitlist export observations -o train.parquet            # parquet output supported
hitlist export binding [filters...] -o binding.csv      # binding-assay index (separate from MS)
hitlist export samples [--class I|II]                   # per-sample conditions (YAML curation only)
hitlist export summary                                  # species x class summary
hitlist export counts [--source iedb|cedar|merged|all]  # peptide counts per PMID
hitlist export alleles                                  # validate YAML alleles with mhcgnomes
hitlist export data-alleles                             # validate all IEDB/CEDAR alleles

MS vs binding: two separate indexes

Each hitlist data build writes two parquet files to ~/.hitlist/:

• observations.parquet — MS-eluted immunopeptidome (IEDB + CEDAR + curated supplementary).
• binding.parquet — binding-assay rows (peptide microarray, refolding, MEDi, and quantitative-tier measurements like Positive-High/Intermediate/Low).

The two indexes are never mixed. Supplementary data is MS-only. Use hitlist export observations for immunopeptidome training data and hitlist export binding for affinity / binding-predictor work. They share the same schema plus the mappings-sidecar gene annotations, so the same filters apply to both.

Filters on hitlist export observations

Flag	Values
--class	I, II, non classical
--species	Any species variant (normalized via mhcgnomes)
--mono-allelic / --multi-allelic	Filter on is_monoallelic
--instrument-type	Orbitrap, timsTOF, TOF, QqQ, ...
--acquisition-mode	DDA, DIA, PRM
--min-allele-resolution	four_digit, two_digit, serological, class_only
--mhc-allele	Exact match on mhc_restriction after allele normalization. Repeatable / comma-separated.
--gene	Symbol, Ensembl ID, or old alias (HGNC synonym lookup). Repeatable / comma-separated. Requires the mappings sidecar (default-on at build).
--gene-name	Exact match on gene_name column (no HGNC lookup)
--gene-id	Exact match on gene_id column (ENSG)
--serotype	HLA serotype: locus-specific (A24, B57, DR15) or public epitope (Bw4, Bw6). Matches any serotype the allele belongs to, so --serotype Bw4 returns A*24:02, B*27:05, B*57:01, etc. Repeatable / comma-separated.
--output / -o	.csv or .parquet

All filters are pushed down to the parquet reader (pyarrow), so --gene PRAME reads only the matching row groups — typically milliseconds rather than a full table scan. Examples:

• hitlist export observations --gene PRAME --class I -o prame_classI.csv
• hitlist export observations --gene "MART-1" (HGNC resolves to MLANA)
• hitlist export observations --mhc-allele HLA-A*02:01 --mono-allelic
• hitlist export observations --serotype A24 (locus-specific)
• hitlist export observations --serotype Bw4 (public epitope — A23/24/25/32, B13/27/44/51/52/53/57/58)

Filters on hitlist export binding

Same shape as the observations filters minus the MS-specific ones (--mono-allelic, --instrument-type, --acquisition-mode). --source accepts only iedb or cedar — supplementary data is MS-only and never appears in the binding index.

hitlist export binding --gene PRAME --class I -o prame_binding.csv
hitlist export binding --mhc-allele HLA-A*02:01 --serotype Bw4

A note on mono-allelic curation

Mono-allelic is a PMID-level flag, not a per-sample property. Curation lives in pmid_overrides.yaml (see mono_allelic_host and ms_samples). Rows can legitimately have is_monoallelic=True with an empty mhc_restriction — for example, supplementary contaminant peptides under a mono-allelic PMID override carry the flag but not a per-row allele. If your downstream pipeline needs a strict "mono-allelic AND has allele" subset, post-filter on is_monoallelic & mhc_restriction.str.startswith("HLA-").

Reports

hitlist report [--class I|II] [--output report.txt]

Development

./develop.sh    # install in dev mode
./format.sh     # ruff format
./lint.sh       # ruff check + format check
./test.sh       # pytest with coverage (~3 min)
./deploy.sh     # lint + test + build + upload to PyPI

See docs/pmid-curation.md for the curation YAML format and per-study overrides.