Macrophages are formed from peripheral blood precursors called monocytes. They are the first line of defense against invading disease-causing organisms. Macrophages attack invaders by a process of phagocytosis (engulfment and breakdown of particles). They can also help initiate immune responses by T lymphocytes.
The cellular environment of macrophages is very hostile to most microbes. However, the parasites that cause leishmaniasis (Leishmania spp.) can enter and remain in the marcrophage (the primary host of the parasite). This parasite is transmitted by sandflies and treatment of the various forms of leishmaniais depends on the type of infection (visceral, mucosal, or cutaneous) and host and parasite factors.
To study the macrophage-parasite interaction at the molecular level, scientists conducted RNA sequencing experiments to study the gene expression profile of infected macrophages and the leishmaniasis parasite. The macrophages used in the experiments were derived from human monocytes collected from peripheral blood. These macrophages were infected in the laboratory with two different Leishmania species and the RNA was collected over various time points for sequencing. The genetic reprogramming related to the macrophage and Leishmania species interactions was then examined.
The study results revealed that there is a strong Leishmania-specific response of macrophages in the early stage of the parasite infections, but this wanes at later periods. A similar pattern was seen with the parasite RNA. In cell cultures, the infected macrophages show characteristic clustering behaviors. However, over time, they began to behave as macrophages that only ingested inert particles. The majority of the programming that takes place appears to occur soon after the parasite enters the macrophage. The parasite establishes itself within the macrophage, leaving specific gene expression signatures that reflect this Leishmania-macrophage relationship.
This new information helps to uncover how pathogens can evade the immune defenses. It will also allow a better understanding of the cellular and molecular changes that allow parasites to survive within invaded cells. Not only can this knowledge apply to the species studied, but to other Leishmania spp. and other infective agents that have the ability to evade immune attack and live within host cells.
Here at HemaCare, we are very excited about new research stemming from Macrophages. If you’re interested in furthering your research, feel free to visit our site or contact us at (877) 397-3087 today!
Fernandes, Maria Cecilia et al. "Dual Transcriptome Profiling Ofleishmania-Infected Human Macrophages Reveals Distinct Reprogramming Signatures". N.p., 2016. Print.