120-kD surface glycoprotein of Pneumocystis carinii is a ligand for surfactant protein A.
J Clin Invest
; 89(1): 143-9, 1992 Jan.
Article
en En
| MEDLINE
| ID: mdl-1530850
ABSTRACT
Pneumocystis carinii is the most common cause of life-threatening pneumonia in immunocompromised patients. In the current study, surfactant protein A (SP-A), the major nonserum protein constituent of pulmonary surfactant, is demonstrated to bind P. carinii in a specific and saturable manner. SP-A is surface bound and does not appear to be internalized or degraded by the P. carinii organism. Furthermore, SP-A binding to P. carinii is time- and calcium-dependent and is competitively inhibited by mannosyl albumin. In the absence of calcium or the presence of excess mannosyl albumin, SP-A binding to P. carinii is reduced by 95 and 71%, respectively. SP-A avidly binds P. carinii with a Kd of 8 x 10(-9) M and an estimated 8.4 x 10(6) SP-A binding sites per P. carinii organism, as determined from Scatchard plots. SP-A is shown to bind P. carinii in vivo, and a putative binding site for SP-A on P. carinii is demonstrated to be the mannoserich surface membrane glycoprotein gp120. These findings suggest that P. carinii can interact with the phospholipid-rich material in the alveolar spaces by specifically binding a major protein constituent of pulmonary surfactant.
Texto completo:
1
Colección:
01-internacional
Banco de datos:
MEDLINE
Asunto principal:
Pneumocystis
/
Neumonía por Pneumocystis
/
Proteolípidos
/
Surfactantes Pulmonares
/
Albúmina Sérica
/
Proteínas Fúngicas
/
Glicoproteínas de Membrana
Tipo de estudio:
Prognostic_studies
Límite:
Animals
Idioma:
En
Revista:
J Clin Invest
Año:
1992
Tipo del documento:
Article