Complement system and host defense against staphylococcal endophthalmitis.
OBJECTIVE
The authors studied the role of the complement system in host defense against Staphylococcus epidermidis and S. aureus endophthalmitis.


METHODS
Guinea pigs in the S. epidermidis model received an intravitreal injection of 7000 viable organisms, and guinea pigs in the S. aureus model received 50 viable organisms. The experimental animals in each model were decomplemented with intraperitoneal (IP) injections of cobra venom factor, whereas the control animals received IP injections of normal saline. Mean log bacterial counts in the vitreous and mean serum complement titers were compared in the experimental and control animals in each model on days 1, 2, 3, and 7.


RESULTS
In the S. epidermidis model, mean log bacterial counts in the vitreous were significantly higher in the experimental group than the control group on days 1 and 2 (P < 0.01) and on day 3 (P < 0.05). Mean serum complement titers were significantly lower in the experimental group at all days (P < 0.01). In the S. aureus model, mean log bacterial counts in the vitreous were significantly higher in the experimental group than the control group on day 2 (P < 0.05) and day 3 (P < 0.01). Mean serum complement titers were significantly lower in the experimental group on days 1, 2, and 3 (P < 0.01), but not on day 7.


CONCLUSIONS
These results suggest that decomplemented guinea pigs show impaired host defense to S. epidermidis and S. aureus endophthalmitis and that this defense is restored as complement levels approach normal.
Giese
M J
MJ
Jules Stein Eye Institute, University of California at Los Angeles 90024-1771.
Mondino
B J
BJ
Glasgow
B J
BJ
Sumner
H L
HL
Adamu
S A
SA
Halabi
H P
HP
Chou
H J
HJ
D000818:Animals; D015169:Colony Count, Microbial; D015941:Complement Hemolytic Activity Assay; D003165:Complement System Proteins / Q000502:physiology*; D004195:Disease Models, Animal; D009877:Endophthalmitis / Q000276:immunology* / Q000382:microbiology; D015818:Eye Infections, Bacterial / Q000276:immunology* / Q000382:microbiology; D006168:Guinea Pigs; D013203:Staphylococcal Infections / Q000276:immunology* / Q000382:microbiology; D013211:Staphylococcus aureus; D013212:Staphylococcus epidermidis
D003165:Complement System Proteins