Antibody response to group B streptococcus type III and AB blood group antigens induced by pneumococcal vaccine.

The effect of pneumococcal vaccination on antibodies to Streptococcus pneumoniae type 14, group B streptococcus type III, and AB blood group antigens was studied in 40 vaccinated adults. Fourfold or greater increases in type-specific IgG antibody to Pn-14 were found in 26 of 40 vaccines (mean increase 6.4-fold) and against GBS-III in 16 of the 40 (mean increase 2.9-fold) by an indirect immunofluorescence assay. However, only six of the 26 vaccinees with low levels (titers less than or equal to 20) of GBS-III antibody in prevaccination sera developed titers greater than 20 after vaccination. Thus, vaccination with polyvalent pneumococcal vaccine does not reliably induce high levels of IF antibody to GBS-III. Fourfold or greater increases in IgG isohemagglutinins against blood group A cells were also found in 22 of 27 vaccines (mean increase 4.5-fold) and against blood group B cells in nine of 34 (mean increase 1.7-fold) using the indirect anti-human globulin test. Chromatographic fractionation of selected sera confirmed that the anti-A isohemagglutinins stimulated in group O subjects were of the IgG class. Thus, pneumococcal vaccination during incompatible pregnancy could potentiate AO hemolytic disease of the newborn infant.

Prevalence of type-specific group B streptococcal antibody in pregnant women.

Immunoglobulin G antibody against the four major serotypes of group B streptococcus was measured by indirect immunofluorescence in the sera of 200 consecutive pregnant women seen in the obstetric screening clinic of an urban teaching hospital. Antibody was detectable in 26% of undiluted sera against serotype Ia, 52% against serotype Ib, 82% against serotype II, and 45% against serotype III. Only 9% had antibody against all four GBS types. When serotype-specific antibody prevalences in 108 women with GBS vaginal colonization were compared with prevalences in noncolonized women, only women colonized with GBS type Ia were more likely to have antibody against Ia than noncolonized women. Antibody prevalences in sera from 54 mothers whose infants developed invasive GBS disease were significantly lower than those in colonized or noncolonized women. Since low titers of IF antibody to GBS III were present in some sera from mothers of infected infants, the data were analyzed based on IF antibody titers associated with passive protection in a chick embryo model of GBS septicemia. None of the sera from mothers of infected infants had antibody levels associated with chick embryo protection. Less than 10% of women had titers associated with chick embryo protection. These data suggest that the majority of pregnant women lack immunity to GBS, regardless of colonization status.

Quantitative nitrobluetetrazolium reduction by normal newborn monocytes.

The phagocytosis-induced metabolic burst of human newborn monocytes, as evaluated by their capacity to reduce NBT, was comparable to that of adult monocytes. The NBT reduction assay constitutes a simple method of ascertaining the functional capacity of human monocytes.