1.In vitro adhesion and invasion by Cladosporium sphaerospermum in human bronchial epithelial cells (BEAS-2B) and human pulmonary alveolar epithelial cells (HPAEpiC)
Lo, S.G. ; Wong, S.F ; Mak, J.W. ; Choo, K.K. ; Ng, K.P.
Tropical Biomedicine 2019;36(4):958-971
Cladosporium spores are ubiquitous in indoor and outdoor environment and may
potentially trigger allergic responses upon inhalation. To date, there is limited investigation
on the fate of Cladosporium spores after being inhaled into the respiratory tract. This study
was conducted to investigate the interaction of Cladosporium sphaerospermum with Human
Bronchial Epithelial Cells (BEAS-2B) and Human Pulmonary Alveolar Epithelial Cells
(HPAEpiC). C. sphaerospermum conidia were harvested and co-cultured with BEAS-2B or
HPAEpiC cells for 72 hours. At each time point (30 minutes, 2, 4, 24, 48 and 72 hours),
adherence and invasion of the cells by C. sphaerospermum conidia (and hyphae) were
investigated by immunofluorescence staining. This study demonstrated the adherence and
internalization of C. sphaerospermum conidia within these epithelial cells. In addition, the
conidia were able to germinate and invade the epithelial cells. The ability of the fungal
conidia to adhere, internalize, germinate and invade both the bronchial and alveolar epithelial
cells of the respiratory tract in vitro might contribute to the understanding of the pathogenesis
of Cladosporium in respiratory infection and allergy in vivo.
INTRODUCTION
Cladosporium species is a member of the
phylum Ascomycota. The common species
include C. herbarum, C. cladosporioides
and C. sphaerospermum. This genus has
worldwide distribution. Aerobiological
studies reported that majority of fungal
spores in outdoor air is from the phyla
Ascomycota and Basidiomycota, while
Cladosporium is one of the most studied
allergenic Ascomycetes fungi (Knutsen et
al., 2012). Cladosporium spores are found
abundantly in indoors and outdoors at
approximately 18/m3 and 141/m3 respectively
(Codina et al., 2008).
As an imperfect dematiaceous fungus,
Cladosporium species causes opportunistic
infections such