Human DNA is easy to find in the environment, with samples of such good quality it can identify individual people. That’s both a boon and a burden for researchers.

A new study out of the University of Florida has found that human DNA samples, some of extremely high quality, are easily found in the environment wherever researchers looked, offering both a bounty for scientific research but also an ethical dillema not easily solved.

Shutter2U/iStock.

In a paper published this week in Nature Ecology and Evolution, the researchers from the University of Florida’s (UF) Whitney Laboratory for Marine Bioscience and Sea Turtle Hospital took environmental DNA (eDNA) samples from water, soil, and air collections in its ongoing study of viral cancers among sea turtles, and looked for human DNA among the turtle DNA the team had already been collecting.

Understanding how major histocompatibility complex class (MHC) molecules and peptides interact within the immune system is crucial for the advancement of biological sciences and medicine. A better understanding of how and when the immune system is activated can lead to treatments in diseases such as cancer or for the development of new vaccines.

MHC-peptide exchange technology attempts to replicate the immune response where peptide exchange occurs on an MHC molecule. The combination of the peptide sequence and the MHC molecule define the strength of the binding affinity resulting in a weak or strong interaction. In order for in vivo T cell epitope to be immunogenic, it must be able to bind a compatible MHC molecule and remain bound for long enough to be presented to and recognized by T cells to elicit an immune response. This shows that a strong binding affinity of MHC/peptide sequence in vitro may indicate potential strong immune interactions of antigen specific T cells in the desired model test sample. Ultimately obtaining this crucial peptide-MHC partnership, where binding affinity is the optimal amount, and the subsequent T cell reaction is sufficient for a therapeutic response, is difficult and cumbersome. There are many different technologies to explore MHC-peptide binding.

Chimeric antigen receptor (CAR) therapies involve the use of engineered receptors capable of redirecting immune cells to recognize and destroy cancer cells expressing a specific antigen. Currently, CAR-T cells, T cells equipped with CAR, dominate the field of CAR therapy. Since 2017, over 700 clinical trials involving CAR-T therapy have been registered and the U.S. Food and Drug Administration (FDA) has approved six CAR-T therapies for the treatment of leukemia, lymphomas, and multiple myeloma (Fig. 1) ^[1]. However, despite its clinical significance, several factors contribute to the limitations of CAR-T therapy. First, as collecting T cells is costly and time-consuming, this may not be feasible for patients already suffering from a compromised immune system. Second, CAR-T therapies mainly focus on treating hematological malignancies, having limited effectiveness in treating solid tumors. Third, CAR-T cells struggle to penetrate the tumor microenvironment (TME), which can hinder their therapeutic function. To overcome these limitations, promising CAR designs have emerged for multi-target CAR-T alongside novel therapies that utilize other immune cell types such as CAR-Natural killer (NK) and CAR-Macrophage (M) cells.

Figure 1. Timeline of CAR-T FDA approvals in the US. B-ALL, B cell acute lymphoblastic leukemia; LBCL, large B cell lymphoma; MCL, mantle cell lymphoma; MM, multiple myeloma; R/R, relapsed/refractorySource: adapted from Maakaron, J, et al. 2022^[1].

Beware, bad guys—your DNA is in the air.