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.
Channing Laboratory, Brigham and Women's Hospital, and Harvard Medical School, Boston, Massachusetts 02115, USA. mwessels@channing.harvard.edu
M R
MR
Wessels
D L
DL
Kasper
K D
KD
Johnson
L H
LH
Harrison
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