Association between low concentrations of antibodies to protein alpha and Rib and invasive neonatal group B streptococcal infection.
BACKGROUND
Infection with group B streptococci (GBS) is a serious neonatal disease. The GBS cell surface proteins alpha and Rib elicit protective immunity in animal models and have been suggested as potential antigens in a vaccine against human GBS disease.


OBJECTIVE
To test the hypothesis that transplacentally transferred maternal antibodies to GBS proteins contribute to the protection of the neonate from GBS infection.


METHODS
Thirty neonates with invasive infection were included in a case-control study. IgG antibody concentrations were measured in sera from these neonates, their mothers, and from 60 non-infected controls, neonates as well as mothers.


RESULTS
A clear association was found between concentrations of antibody to proteins alpha and Rib in neonatal and maternal sera, indicating that transplacental transfer had occurred. Moreover, low concentrations of antibodies to alpha and Rib in neonatal sera were associated with invasive GBS infection caused by strains expressing the Rib protein. The odds ratio was 0.0007 (95% confidence interval 0.000 to 0.54) for antibodies to alpha and 0.002 (95% confidence interval 0.000 to 0.57) for antibodies to Rib.


CONCLUSIONS
These findings support the notion that antibodies to GBS surface proteins contribute to the protection against neonatal infection.
Larsson
C
C
Department of Medical Microbiology, Lund University, Lund, Sweden. charlotte.u.larsson@vgregion.se
Lindroth
M
M
Nordin
P
P
Stålhammar-Carlemalm
M
M
Lindahl
G
G
Krantz
I
I
D000328:Adult; D000907:Antibodies, Bacterial / Q000097:blood*; D000942:Antigens, Bacterial / Q000276:immunology; D000954:Antigens, Surface / Q000276:immunology; D001426:Bacterial Proteins / Q000276:immunology*; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D005865:Gestational Age; D006801:Humans; D007074:Immunoglobulin G / Q000097:blood; D007231:Infant, Newborn; D008565:Membrane Proteins / Q000276:immunology; D013290:Streptococcal Infections / Q000276:immunology*; D013292:Streptococcus agalactiae / Q000276:immunology*
D000907:Antibodies, Bacterial; D000942:Antigens, Bacterial; D000954:Antigens, Surface; D001426:Bacterial Proteins; D007074:Immunoglobulin G; D008565:Membrane Proteins; C081277:Rib protein, Streptococcus agalactiae; C077961:alpha C protein, group B streptococci