Document 0440
 DOCN  M9440440
 TI    A novel in situ model to study Pneumocystis carinii adhesion to lung
       alveolar epithelial cells.
 DT    9404
 AU    Pavia-Ruz N; Ortega-Barria E; Alroy J; Pereira ME; Department of
       Medicine, New England Medical Center Hospitals,; Boston, MA 02111.
 SO    J Immunol Methods. 1994 Jan 3;167(1-2):161-71. Unique Identifier :
       AIDSLINE MED/94141191
 AB    Pneumocystis carinii, an extracellular parasite thriving in the lungs of
       immunosuppressed mammals, is a major cause of death in AIDS patients in
       the USA. As a prelude to growth, the parasite adheres mostly to type I
       pneumocytes lining the alveolar spaces. The mechanism of adherence
       remains unknown, largely because of difficulties in isolating type I
       pneumocytes and maintaining them in vitro. As a first step to understand
       P. carinii adherence to its natural substrate, we developed an in situ
       method to directly study parasite binding to lung alveolar cells. We
       used formaldehyde-fixed paraffin-embedded sections of normal rat lung as
       substrate for adhesion. As in its binding to the lungs in vivo, P.
       carinii adhered preferentially to type I pneumocytes. Adherence was
       saturable, time and dose dependent, and selectively blocked by
       glycoconjugates, in particular bovine submaxillary mucin, fetuin, and
       asialofetuin, suggesting that it may be mediated by a lectin type of
       interaction. Further, IgG of rats with P. carinii pneumonia inhibited
       adherence, suggesting that it may react with parasite ligands involved
       in the recognition of type I cell receptors. Our results demonstrate the
       usefulness of the in situ model for studying the mechanisms of P.
       carinii adherence to alveolar cells. In addition, this method may be
       valuable for identifying neutralizing antibodies and drugs potentially
       useful for controlling the infection in vivo.
 DE    Animal  Antibodies, Fungal/PHARMACOLOGY  Carbohydrates/PHARMACOLOGY
       Cell Adhesion/DRUG EFFECTS/*PHYSIOLOGY  Cell Line  Comparative Study
       Fluorescein-5-isothiocyanate  Glycoproteins/PHARMACOLOGY
       Histocytological Preparation Techniques  Human  Lectins  *Models,
       Biological  Pneumocystis carinii/CYTOLOGY/IMMUNOLOGY/*PHYSIOLOGY
       Pulmonary Alveoli/CYTOLOGY/*PHYSIOLOGY  Rats  Stains and Staining
       Support, Non-U.S. Gov't  Support, U.S. Gov't, P.H.S.  JOURNAL ARTICLE

       SOURCE: National Library of Medicine.  NOTICE: This material may be
       protected by Copyright Law (Title 17, U.S.Code).