Interaction of Pseudomonas aeruginosa with human tear fluid components.
OBJECTIVE
Reflex human tears bind Pseudomonas aeruginosa bacteria and prevent them from invading corneal epithelial cells. In this study, we assessed the effect of eye closure and the role of sialoglycoprotein (SG) in tears on bacterial binding and invasion.


METHODS
Human tears (reflex and closed-eye) were collected using a microcapillary tube. Reflex tears were separated into 13 fractions by high-performance liquid chromatography while high-molecular-weight components from closed-eye tears were separated into an SG/mucin fraction and a nonmucin fraction. Bacterial binding was quantified by viable counts and bacterial invasion was tested using the gentamicin survival technique.


RESULTS
Closed-eye tears bound significantly more bacteria than open-eye tears. Fractionation of reflex tears showed that 11 out of the 13 fractions bound bacteria, while all 13 fractions significantly reduced bacterial invasion of corneal epithelial cells. Surprisingly, the SG/mucin component of closed-eye tears resisted bacterial binding and had no significant effect on bacterial invasion.


CONCLUSIONS
P. aeruginosa bacteria bind more efficiently to closed-eye tears than to open-eye tears. The mechanism by which tears bind bacteria and protect against invasion does not require SG/mucin, as this fraction of closed-eye tears does not contain either activity.
McNamara
Nancy A
NA
Morton D. Sarver Laboratory for Cornea and Contact Lens Research, School of Optometry, University of California, Berkeley, California, USA. nam@itsa.ucsf.edu
Andika
Renisa
R
Kwong
Mary
M
Sack
Robert A
RA
Fleiszig
Suzanne M J
SM
D001422:Bacterial Adhesion; D001767:Blinking; D015153:Blotting, Western; D002460:Cell Line; D015169:Colony Count, Microbial; D004591:Electrophoresis, Polyacrylamide Gel; D019573:Epithelium, Corneal / Q000382:microbiology; D015817:Eye Infections / Q000517:prevention & control; D005136:Eye Proteins / Q000502:physiology*; D006801:Humans; D007071:Immunoglobulin A, Secretory / Q000502:physiology; D009077:Mucins / Q000502:physiology; D011552:Pseudomonas Infections / Q000517:prevention & control; D011550:Pseudomonas aeruginosa / Q000502:physiology*; D012795:Sialoglycoproteins / Q000502:physiology; D013666:Tears / Q000378:metabolism*
D005136:Eye Proteins; D007071:Immunoglobulin A, Secretory; D009077:Mucins; D012795:Sialoglycoproteins; C042434:tear proteins