Decreased expression of mannose-specific adhesins by Escherichia coli in the colonic microflora of immunoglobulin A-deficient individuals.

• Most Escherichia coli isolates can express type 1 fimbriae with mannose-specific adhesins. These adhesins bind to the oligosaccharide chains of secretory immunoglobulin A (IgA). Thus, in addition to specific antibody activity, secretory IgA possesses a broad reactivity with bacteria expressing type 1 fimbriae. The absence of secretory IgA in colonic secretions, as seen in IgA deficiency, might therefore alter the ability of type 1-fimbriated E. coli to colonize the large intestines of these individuals. In the present study, 10 E. coli isolates from each of 17 IgA-deficient and 17 age-matched control individuals were assessed for the carriage of the fim gene cluster by DNA-DNA hybridization and for the expression of type 1 fimbriae by hemagglutination of guinea pig erythrocytes. The contribution of type 1-fimbria-mediated adherence to HT-29 colonic cells was also analyzed. The proportion of fim+ E. coli isolates was lower in IgA-deficient than in control individuals (74 versus 94%, P < 0.05), as was the proportion of isolates expressing type 1 fimbriae in vitro (69% versus 85%, P < 0.05). The median mannose-sensitive adherence to HT-29 cells was lower for isolates from IgA-deficient individuals than from the controls (9 versus 26 bacteria per cell, P < 0.05). Isolates expressing type 1 fimbriae showed lower adherence to HT-29 cells when they were derived from IgA-deficient individuals than when they were derived from control individuals (15 versus 27 bacteria per cell, P < 0.05). The results suggest that the interaction of type 1 fimbriae with secretory IgA contributes to the large intestinal colonization by these bacteria.

Ämnesord

MEDICIN OCH HÄLSOVETENSKAP  -- Klinisk medicin -- Gastroenterologi (hsv//swe)

MEDICAL AND HEALTH SCIENCES  -- Clinical Medicine -- Gastroenterology and Hepatology (hsv//eng)

MEDICIN OCH HÄLSOVETENSKAP  -- Klinisk medicin -- Infektionsmedicin (hsv//swe)

MEDICAL AND HEALTH SCIENCES  -- Clinical Medicine -- Infectious Medicine (hsv//eng)

MEDICIN OCH HÄLSOVETENSKAP  -- Medicinska och farmaceutiska grundvetenskaper -- Mikrobiologi inom det medicinska området (hsv//swe)

MEDICAL AND HEALTH SCIENCES  -- Basic Medicine -- Microbiology in the medical area (hsv//eng)

Nyckelord

Adhesins

Bacterial

genetics

metabolism

Adult

Aged

Binding Sites

Case-Control Studies

Colon

microbiology

Enterobacteriaceae

isolation & purification

Escherichia coli

genetics

isolation & purification

metabolism

Female

Fimbriae

Bacterial

genetics

metabolism

Genes

Bacterial

Genotype

Humans

IgA Deficiency

metabolism

microbiology

Male

Mannose

metabolism

Middle Aged

Publikations- och innehållstyp

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