Taste for Blood: Hemoglobin as a Nutrient Source for Pathogens

Hemoglobin, which gives blood its red color, is perhaps the most recognized and well studied protein in nature. It is also a critical molecule during infection, as many microbes rely on hemoglobin to grow within their hosts. Here, we review the importance of hemoglobin to vertebrate physiology and how humans attempt to conceal hemoglobin from invading pathogens. We also provide examples of the elaborate mechanisms employed by microbes to acquire hemoglobin during infection. Finally, we discuss how genetic variations within hemoglobin affect susceptibility to infectious diseases.