Leach · Science (New York, N.Y.) 1996 · Preclinical animal experimental study · n=?

Enhancement of antitumor immunity by CTLA-4 blockade.

Cited 3950 times in the scientific literature.

Level 5 - mechanism / opinion, no new human data

Preclinical in vivo animal study.

PubMed 8596936 · doi:10.1126/science.271.5256.1734 · record verified 2026-08-26

What was done

Investigators tested the in vivo administration of blocking antibodies against CTLA-4, a negative regulator of T-cell activation, in tumor-bearing models, evaluating effects on tumor rejection (including preestablished tumors) and subsequent resistance to secondary tumor exposure.

What was found

The abstract provides no quantitative metrics, percentages, or sample sizes. Qualitatively, anti-CTLA-4 antibody administration caused the rejection of tumors, including preestablished tumors, and conferred protective immunity against secondary tumor cell challenge.

Why it matters

This seminal study provided the proof-of-concept for immune checkpoint blockade in oncology, showing that releasing inhibitory signals on T cells can trigger effective antitumor immunity.

Limits

The findings are limited to preclinical animal models and cannot directly establish human clinical efficacy or safety from the abstract. The abstract reports no numerical outcomes, exact experimental protocols, animal strain information, or adverse effect data.

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