PERSISTENCE OF NONTYPABLE HAEMOPHILUS-INFLUENZAE IN ADENOID MACROPHAGES - A PUTATIVE COLONIZATION MECHANISM

That nontypeable H. influenzae (NTHI) can reside intracellularly in hu man adenoid tissue has been suggested by use of in situ hybridization of a fluorescein labelled 16S rRNA-targeted oligonucleotide probe (FIS H). Adenoid tissues from 43 children operated on in a clinically infec tion-free interval were investigated. FISH revealed H. influenzae in m acrophagelike cells, located subepithelially in the crypts in all 43 a denoids. Furthermore, H. influenzae was detected in 22/22 adenoids usi ng immunohistochemistry with the monoclonal antibody MAHI-3 recognizin g a consented H. influenzae LPS inner-core region. FISH and staining w ith monoclonal antibodies against immunophenotypic markers were perfor med simultaneously in order to characterize the cellular interrelation s in this microenvironment. The findings of widespread presence of H. influenzae in cells of which some strongly expressed the CD14 marker o f the monocyte/macrophage lineage may correspond to an important aspec t of the colonization mechanisms whereby NTHI persists in the nasophar ynx of children.