Mechanism of antibody-mediated reduction of nasopharyngeal colonization by Haemophilus influenzae type b studied in an infant rat model.
The mechanism of antibody-mediated reduction of Haemophilus influenzae type b (Hib) carriage was studied in the infant rat colonization model. Monoclonal Hib polysaccharide (PS) antibody (MAb) given intranasally or intraperitoneally and human secretory anti-Hib PS IgA given intranasally inhibited colonization by Hib during the entire follow-up period (2-48 h after challenge) but did not affect colonization by Hi, a noncapsulated variant of Hib. F(ab')2 fragments, prepared from the MAb or from human serum anti-Hib IgG reduced Hib colonization as efficiently as the uncleaved molecules. Complement depletion by cobra venom treatment had no effect on the antibody-mediated reduction of Hib colonization. These results indicate that Fc-mediated activities of immunoglobulins are not essential in the reduction of Hib colonization. Instead, antibodies to Hib most likely reduce colonization by a direct effect on growth of the bacteria or their adherence to the nasopharyngeal mucosa.
Kauppi-Korkeila
M
M
National Public Health Institute, Helsinki, Finland.
van Alphen
L
L
Madore
D
D
Saarinen
L
L
Käyhty
H
H
D000818:Animals; D000907:Antibodies, Bacterial / Q000276:immunology*; D000911:Antibodies, Monoclonal / Q000737:chemistry / Q000276:immunology* / Q000627:therapeutic use*; D003165:Complement System Proteins / Q000276:immunology / Q000378:metabolism; D014644:Genetic Variation; D006192:Haemophilus Infections / Q000276:immunology* / Q000382:microbiology / Q000517:prevention & control*; D006193:Haemophilus influenzae / Q000235:genetics / Q000254:growth & development* / Q000276:immunology*; D007070:Immunoglobulin A / Q000276:immunology* / Q000627:therapeutic use*; D007140:Immunoglobulin Fab Fragments / Q000276:immunology / Q000627:therapeutic use; D007074:Immunoglobulin G / Q000737:chemistry / Q000276:immunology; D007700:Kinetics; D009305:Nasopharynx / Q000276:immunology / Q000382:microbiology; D011135:Polysaccharides, Bacterial / Q000276:immunology*; D051381:Rats; D017208:Rats, Wistar; D013047:Specific Pathogen-Free Organisms
D000907:Antibodies, Bacterial; D000911:Antibodies, Monoclonal; D007070:Immunoglobulin A; D007140:Immunoglobulin Fab Fragments; D007074:Immunoglobulin G; D011135:Polysaccharides, Bacterial; D003165:Complement System Proteins