AffinityImmuno Products

Introduction

BTN1A1 sits within the major histocompatibility complex class I region on chromosome 6 and encodes Butyrophilin-1, an immunoglobulin superfamily member built around a B30.2/SPRY domain that anchors it in the apical plasma membrane of mammary epithelial cells. There it acts as a docking receptor that tethers cytoplasmic lipid droplets to the cell surface, a step required for the budding, secretion, and structural stability of the fat globules found in milk. Independent of its role in lactation, this same surface protein dampens T-cell immunity: engaging Butyrophilin-1 on CD4-positive and CD8-positive T cells that have been triggered through anti-CD3 stimulation curbs their proliferation, slows their metabolic activity, and reduces their output of the cytokines interleukin-2 and interferon-gamma. The gene is thought to have originated through exon shuffling across separate ancestral gene lineages, which may explain why a single protein serves such distinct physiological roles in nutrition and immune regulation.

Beyond its established role anchoring lipid droplets during milk-fat secretion, Butyrophilin-1 independently dampens T-cell proliferation and cytokine output when engaged on CD4+ and CD8+ T cells, giving this assay dual relevance to lactation-biology and T-cell immunoregulation research.

Principle of the Assay

This kit uses a sandwich enzyme immunoassay format in which the microtiter plate wells come pre-coated with a capture antibody specific to Human BTN1A1. Standards or samples are added to the appropriate wells together with a biotin-conjugated detection antibody that also recognizes Human BTN1A1. Avidin conjugated to horseradish peroxidase (HRP) is then added to each well and allowed to incubate. Upon addition of TMB substrate solution, a colorimetric signal develops exclusively in wells where Human BTN1A1, the biotin-conjugated antibody, and the avidin-HRP conjugate are all present. The enzymatic reaction is stopped by the addition of sulphuric acid solution, and the resulting color change is measured spectrophotometrically at 450 nm ± 10 nm. Human BTN1A1 concentrations in the samples are determined by comparing the optical density of each sample against the standard curve.