NK and T cells nearly merge in TEDDY’s embedding, and the protein differences predicted from it are squeezed
Superseded by v3E3 rejected “the NK–T loss is in the readout or pooling and is repairable on frozen TEDDY”: a layer-mean MLP (R1) and attention pooling over gene tokens (R2) both told NK from T less accurately than our head (−0.0409 and −0.1925 at coverage 0.9, registered losses). On the registered within-donor pairs the head’s gap ratio is 0.1169 on flagged vs 0.3985 on unflagged pairs, with overlapping intervals and mostly from gdT CD158b+ pairs in the weak-key donor; without those pairs 0.4729 vs 0.5137. The ANM test of the gene-mean state (E5-M) is inconclusive: for the attention-pooling readout, a smaller share of its response flows through what pooling discards on look-alike cells (0.085) than on random cells (0.127), for this one observer. E3 → · E5-M →
The principle: a declared candidate retained state is sufficient for a declared readout only if the same state always gives the same readout. Here the candidate is TEDDY’s embedding and the readout the proteins our head predicts from it, so this probes TEDDY’s embedding + our head together. Declaring the state does not establish that it is sufficient: the test rejects it, or, within a candidate set declared in advance, selects the candidate with no violation and the fewest states.
The predictions (TEDDY + head) put the two cells close together; the measured proteins put them far apart.
- Right direction, compressed. NK has the higher predicted CD56 in 68% of pairs, but predicted gaps are a quarter to a third of measured ones (CD335 0.88).
- Not generic shrinkage? (v2 reading) Non-neighbour NK–T pairs keep 0.8–1.5, so v2 tied the loss to near-merged cells. v3 E3: on registered pairs the flagged-vs-unflagged contrast is descriptive only and not robust.
- Partly in our head’s readout? (v2 Mode A probes) A linear probe tells NK from T at every TEDDY layer (held-out AUC 0.991–0.997). On these pairs our head keeps 0.24 / 0.31 / 0.88 / 0.27 of the measured CD56 / CD94 / CD335 / CD3 gap and a linear probe on the embedding about the same (less for CD335), but an MLP probe on the same embedding keeps about twice as much: 0.47 / 0.59 / 0.74 / 0.61 (MLP − head interval above 0 for CD56, CD94 and CD3 at every depth). v3 E3: two trained readouts of frozen TEDDY lost NK-vs-T accuracy to our head.
- Partly mean pooling, partly not in the RNA? (v2 reading) The states of 13 NK/T gene tokens keep more than the gene-mean of the same forward pass (layer 12, MLP: 0.58 / 0.62 / 0.72 / 0.56 vs 0.41 / 0.43 / 0.49 / 0.45), about as much already at the input layer: it is mostly which genes are detected and at what rank, and TEDDY’s layers neither add nor remove much of it. Even the best probe keeps only about half to three-quarters, and CD3E is among the tokens in only 45% of NK and 60% of T pair cells. v2 concluded that a non-linear, token-aware readout of frozen TEDDY could recover part of the NK–T difference; v3 E3 rejected that (attention pooling over gene tokens, R2, lost NK-vs-T accuracy to our head: −0.1925). Caveats: one site; probes, not the head’s objective; token probes fit on 990 random site4 NK/T cells and scored on the 483 pair cells; some intervals overlap.
Experiment 6 redesign prototype (the experiment stays withdrawn; redesigned and registered as v3 E3, E5 and E5-M). Left out: 1053 of the 1,506 pairs, “gdT CD158b+” cells that look NK-like in both predicted and measured protein, likely mislabelled · Mode A reports: linear · MLP / kNN · token · Experiment 6 →












