MATERNAL IMMUNITY AND ANTIBODY-RESPONSE OF NEONATAL MICE TO PNEUMOCOCCAL TYPE-19F POLYSACCHARIDE

The effect of immunization of mothers on the antibody response of their young to pneumococcal type 19F polysaccharide was studied. When 2-week-old BALB/c mice from mothers immunized with 23-valent pneumococcal vaccine during gestation were given an additional dose of the same vaccine, mouse pneumococcal antiserum, or both, they produced higher titers of antibodies to the 19F polysaccharide (1.87 to 4.66-mu-g of 19F immunoglobulin M [IgM] antibody per ml of serum; 0.45 to 0.81-mu-g of IgG antibody per ml of serum) than the control group that did not receive any treatment after birth (0.69-mu-g of 19F IgM antibody per ml; 0.28-mu-g of 19F IgG antibody per ml) (P < 0.01). Furthermore, all 11- to 12-week-old monkeys that received an additional dose of 23-valent vaccine, pneumococcal immunoglobulin, or both produced statistically higher titers of IgG antibody to the 19F polysaccharide than did controls at various ages. The titers (micrograms of IgG antibody per milliliter of serum) were as follows: vaccine group, 7.12 +/- 0.96; control group at 4 months of age, 3.82 +/- 0.74 (P < 0.01); immunoglobulin-treated group, 6.85 +/- 0.76; vaccinated and immunoglobulin-treated group, 7.80 +/- 1.40; control group at 3 months of age, 3.01 +/- 0.61 (P < 0.01). These results suggest that immunization of mothers under certain conditions, such as with an optimum dose of antigen at a critical period of gestation or postnatal development, could provide young infants with an enhanced antibody response to pneumococcal polysaccharide immunogens.