From extending lifespan to bolstering the immune system, the drug’s effects are only just beginning to be understood.
Vaccine-induced macrophages open a new realm of study into remodeling the immune system to reduce the risk of infections during cancer treatment.
January 1, 2017|
ST. JUDE CHILDREN'S RESEARCH HOSPITAL
A. Kamei et al., “Exogenous remodeling of lung resident macrophages protects against infectious consequences of bone marrow-suppressive chemotherapy,” PNAS, doi:10.1073/pnas.1607787113, 2016.
Chemotherapy wipes out cancerous cells and dividing normal cells alike, often particularly damaging those in bone marrow that produce white blood cells. As a patient’s immune system is weakened, even minor infections can become life-threatening. Researchers are exploring ways to circumvent this problem by “remodeling” the immune system prior to chemotherapy.
Below the radar
Akinobu Kamei of St. Jude Children’s Research Hospital and his colleagues identified a class of white blood cell that only becomes active in the lungs of mice following vaccination for a common bacterial strain that causes pneumonia. Like some other immune cells in the lungs, these so-called vaccine-induced macrophages, or ViMs, do not originate in bone marrow, but reside solely in the lungs, likely having derived from progenitor cells in the lungs during embryogenesis.
The St. Jude team found that ViMs are not decimated by chemotherapy like other immune cells—in fact, their numbers don’t dip at all. It’s not clear how ViMs manage this feat, says Kamei, but mice that were vaccinated before chemotherapy, triggering ViMs, survived bacterial infections at much higher rates than unvaccinated mice.
“The future plan,” says Kamei, “is to induce lung tissue [immune] remodeling to compensate for bone marrow suppression after chemotherapy.” Immunology researcher Sandro Vento of Nazarbayev University in Kazakhstan pointed out in an email to The Scientist that the animal-model work is only preliminary. “This is an initial study which opens a new area of research, and it will be important to understand the mechanisms which allow vaccine-induced macrophages to survive chemotherapy.”
January 1, 2017
The authors claim that immune cells found only in the lungs are derived from embryonic stem cells. The newly found cell types protect agains P. aerugenosa infection in immunocompromized patients. That fact is placed into the context of “natural” adaptation of cells and tissues.
"Natural adaptation" can be compared to the natural nutrient energy-dependent pheromone-controlled ecological adaptation over the weekend that occurred in Psuedomonas fluorescens as reported here: Evolutionary Rewiring
...this fast fix evolves in nearly the same way in each independent strain...
This indicates the human body has a repertoire of pathways that link the innate immune system of bacteria to supercoiled DNA via energy-dependent ecological adaptation. All adaptations appear to link broad-based tissue damage from autophagy to specific cell types, but the adaptations are placed into the context of evolution.
That explains why the authors seem to think that the presence of ViMs in the lungs may represent one of many evolved adaptive pathways that must have automagically been naturally selected for tissue diffense in all cell types of all other host tissues in species from microbes to humans.