This video demonstrates an assay to measure the antibody-dependent cellular phagocytosis (ADCP) by breast milk phagocytes. Fluorescently labeled microspheres conjugated to an antigen-antibody complex, are combined with a cell suspension isolated from breast milk to induce antibody-dependent cellular phagocytosis by the phagocytic leukocytes. Upon labeling the cells with antibodies against common leukocyte antigen (CD45), flow cytometry is used to measure the fluorescence intensity of microsphere-positive viable phagocytic leukocytes, indicating the level of ADCP activity.
Protocol
All procedures involving sample collection have been performed in accordance with the institute's IRB guidelines. 1. Target Microsphere preparation Select a relevant target antigen. NOTE: In this example, the recombinant protein V1V2-2F5K was used, which was designed to mimic the trimeric apex of native HIV envelope. Perform biotinylation using a commercial kit (Table of Materials) according to the manufacturer…
Representative Results
Figure 1: Sample flow cytometry data of cells isolated from breast milk. Cells were processed and stained as described in the protocol. (A) Single cells were gated on to eliminate doublets in an FSC-H vs. FSC-A plot as shown, also gating out the small debris <5,000 in FSC-A. (B) This population was used to gate on live cells (which do not stain with the viabi…