Host immune responses during infections with Candida albicans

Candida species are commensals of the mucosal surfaces and the skin in the majority of healthy individuals. Under conditions in which the host defence is diminished, for example in patients who are immunocompromised or have endured major trauma or invasive clinical procedures, Candida species can initiate infections ranging from superficial mucosal to life-threatening invasive disease (Brown et al. Hidden killers: human fungal infections. Science translational medicine 4 (165):165rv113, 2012). In this chapter, we will explore the importance of the host's innate and adaptive immune defence against Candida albicans, the most abundant Candida species causing human infections. The majority of studies to date have focused on invasive C. albicans infections and considerably less is known about mucosal infections, such as oral and vulvovaginal candidiasis. We will discuss how C. albicans is recognized by pattern recognition receptors (PRRs) of the immune system and the role immune and non-immune cells play in the antifungal response to C. albicans. In addition, we will describe strategies developed by C. albicans to evade recognition and destruction by the host immune system.