Human polymorphonuclear-leukocyte inhibition of incorporation of chitin precursors into mycelia of Coccidioides immitis

Human polymorphonuclear leukocytes (PMNLs), when added to arthroconidial suspensions of Coccidioides immitis, markedly inhibit fungal incorporation of the cell-wall precursor N-acetylglucosamine. This effect does not require serum but is facilitated by a heat-labile serum component(s), probably by promoting PMNL atachment to the arthroconidia. Inhibition is entirely reversible within 24 hr. In parallel with this finding, PMNLs exhibited virtually no killing of arthroconidia and (as determined by electron microscopy) did not produce damage to the fungal ultrastructure. PMNLs from a patient with chronic granulomatous disease suppressed fungal incorporation of N-acetyl-glucosamine by only 0%-22% under various conditions, as compared with 54%-85% suppression by PMNLs from normal donors. Our studies demonstrate that PMNLs can influence the metabolism of C immitis and raise the possibility that their presence in coccidioidal histopathology may be an important immediate host defense in limiting progression early after infection.