Adherence Patterns of Histoplasma capsulatum Yeasts to Bat Tissue Sections

Abstract

The adherence of Histoplasma capsulatum yeasts to lung, spleen, liver, gut, and trachea cryosections of Artibeus hirsutus bats and inbred BALB/c mice (control) was studied after in vitro yeast-tissue incubations. Candida albicans yeasts were used as a well-known adherent fungal model in the mice host, and latex beads were used as a negative adherence control. Adhered yeast cells were identified by using crystal violet staining and the immunoperoxidase method with specific antibodies. H. capsulatum yeasts adhered to all tissues tested, mainly in the lung. Moreover, H. capsulatum yeasts adhered preferentially to white and red spleen pulp, in contrast to the dispersed distribution of C. albicans yeasts. H. capsulatum yeasts were mostly found on the sinusoidal face of hepatocytes. In general, the gut showed a higher number of adhered H. capsulatum yeasts than the trachea in both bats and mice. H. capsulatum and C. albicans yeasts developed high selectivity for the lamina propria of the gut. In addition, H. capsulatum yeasts interacted better with the lamina propria and adventitia of the trachea. The number of H. capsulatum yeast cells that adhered to each tissue section type was always greater than the corresponding number of C. albicans yeast cells, and latex beads never adhered to the tissue sections. Controls with anti-H. capsulatum and normal rabbit sera showed a significant blockage of H. capsulatum yeast adherence to lung tissue. This is the first study describing the patterns of H. capsulatum yeast adherence to different bat and mouse tissues.