GrowthInhibition ofCandida albicans byRabbit Alveolar Macrophages

C.albicans. Over an 8-hperiod, plate counts ofC.albicans incubated withalveolar macrophages revealed a decrease incolony-forming units incontrast toC.albicans alone. Inaddition, an assay was developed whichspecifically measured C.albicans [3H]leucine incorporation inthepresenceofalveolar macrophages. Usingthis assay,we observed a 71to93%inhibition ofmacromolecular synthesis inC. albicans whenincubated withalveolar macrophages. Autoradiographic studies showed thattheinhibition ofleucine incorporation was restricted totheingested Candida. Themajorprocess bywhichlarge particles (i.e., >2.5Am)suchasCandidaalbicans and other fungi arecleared fromthelungisprobablythrough themucociliary transport system (4). However, additional clearance mechanisms mustexist forthose large particles whichevade themucociliary action. Thealveolar macrophage (AM)isacandiate forsuchamechanism. Theyhavebeenshown toplaya critical roleintheinactivation of bacteria andclearance ofinert particles (5). In these capacities, theAM aidsinthemaintenanceofanessentially sterile environment in thelungspaces. Todatethere havebeenno reports concerning theinteraction ofC.albicanswiththeAM,although studies withother fungi haveindicated thattheAM hasarather limited roleinprotection ofthehostagainst invasion (2,3). Inthisstudy, we haveinvestigated thein vitro relationship between C.albicans andrabbitAM.Ourdataindicate thattheAM can inhibit thegrowth ofingested C.albicans.