Binding of 99mTc-labelled polyclonal human immunoglobulin to bacteria as a mechanism for scintigraphic detection of infection.
The aim of the present study was to determine whether 99mTc-labelled polyclonal human immunoglobulin (99mTc-HIG) binds to bacteria in vitro as well as in vivo. In vitro, the binding of 99mTc-HIG to various gram-positive and gram-negative bacteria was determined. In vivo, mice were infected with Staphylococcus aureus Cowan I (protein A rich) or S. aureus EMS (protein A deficient) in a thigh muscle and then 99mTc-HIG or 99mTc-labelled human serum albumin (99mTc-HSA) was administered; scintigrams were made 1, 4, and 18 h later. In vitro binding of 99mTc-HIG to bacteria was higher for gram-positive than for gram-negative forms. A positive correlation was found between the protein A content and the degree of binding to S. aureus. This was also found in vivo. The accumulation of 99mTc-HIG at the site of infection was significantly (P less than 0.01) higher than that of 99mTc-HSA, for both strains of S. aureus. It is concluded that vascular permeability cannot fully explain the accumulation of 99mTc-HIG at the site of infection and that binding of 99mTc-HIG to bacteria plays a role in this respect.
Calame
W
W
Department of Infectious Diseases, University Hospital, Leiden, The Netherlands.
Feitsma
H I
HI
Ensing
G J
GJ
Arndt
J W
JW
van Furth
R
R
Pauwels
E K
EK
D000818:Animals; D001419:Bacteria / Q000378:metabolism; D001424:Bacterial Infections / Q000000981:diagnostic imaging*; D005260:Female; D006801:Humans; D007136:Immunoglobulins / Q000378:metabolism; D066298:In Vitro Techniques; D051379:Mice; D011877:Radionuclide Imaging; D013047:Specific Pathogen-Free Organisms; D013667:Technetium / Q000378:metabolism
D007136:Immunoglobulins; C065376:technetium Tc 99m immunoglobulin; D013667:Technetium