Influenza season is just around the corner. With many Americans expected to seek out the flu vaccination starting in September and October, customers will soon be asking if our donors have received the flu shot or are infected with the flu.

We always gather as much information about our donors as possible, and influenza vaccination and reactivity are among the most important characteristics we test for this season. This time of year, we are often asked not only if our donors are vaccinated or infected, but how we know.

Testing Donors for Flu Reactivity

Flu reactivity cannot be detected in PBMC using tetramer staining or by using our recall assay because the number of T cells that recognize any given flu antigen represent fewer than one in 10,000 cells. Instead, we perform a 10-day culture of PBMC with a peptide from influenza, which can reveal influenza reactivity.

After a 10-day primary culture, flu reactive T cells will increase in number to the point where we can detect the production of IFNg. We can also identify flu reactive T cells using fluorescently labeled HLA-peptide tetramers, which bind to the specific T cell receptors so they can be enumerated using flow cytometric analysis.

The graphs below show that after a 10-day culture with the influenza peptide, there is a small, yet distinct, percentage of positive cells. The percentage varies between different donors. In the examples below, donor 355 has a much higher percentage of flu-specific cells than donor 213.

Donor 213

The graph on the left shows staining with HLA-A2/flu peptide. The graph on the right shows staining with HLA-A2/CMV peptide. Cells were gated on CD8+ cells (x-axis).

Donor 355

The graph on the left shows staining with HLA-A2/flu peptide. The graph on the right shows staining with HLA-A2/CMV peptide. Cells were gated on CD8+ cells (x-axis).

Where to Find Donor Flu Reactivity Information

As we collect donor information, we continually update our product listings. Check the product listings for donor details, or give us a call to get the inside scoop on which donors might be the best choice for the experiments you are planning.

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