Antibody responses in invasive group B streptococcal infection in adults.
Nonpregnant adults with group B streptococcus bacteremia were identified by active surveillance in three hospitals. Serum samples collected within 2 days of the time of blood culture were assayed for IgG antibodies to the capsular polysaccharide of the infecting strain: serotype Ia (3 isolates), III (5 isolates), or V (4 isolates). In 7 of 12 bacteremia episodes, the serum level of IgG to the infecting isolate was > or = 3.5 microg/mL, higher than the 1-2 microg/mL level thought to be protective in neonates. Among selected acute-phase sera, 4 of 5 that contained > or = 3.5 microg/mL specific IgG mediated efficient opsonophagocytic killing of the corresponding group B streptococcus isolate in vitro. High levels of specific antibodies during the acute phase of invasive group B streptococcus infection in nonpregnant adults may reflect a rapid antibody response to infection or, in some cases, may indicate that susceptibility is due to defects in other immune effectors.
Wessels
M R
MR
Channing Laboratory, Brigham and Women's Hospital, and Harvard Medical School, Boston, Massachusetts 02115, USA. mwessels@channing.harvard.edu
Kasper
D L
DL
Johnson
K D
KD
Harrison
L H
LH
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000907:Antibodies, Bacterial / Q000097:blood / Q000276:immunology*; D016470:Bacteremia / Q000097:blood / Q000276:immunology* / Q000382:microbiology; D005260:Female; D006801:Humans; D007074:Immunoglobulin G / Q000097:blood / Q000276:immunology*; D008297:Male; D008875:Middle Aged; D012703:Serotyping; D013290:Streptococcal Infections / Q000097:blood / Q000276:immunology* / Q000382:microbiology; D013292:Streptococcus agalactiae / Q000145:classification / Q000276:immunology* / Q000302:isolation & purification
D000907:Antibodies, Bacterial; D007074:Immunoglobulin G