Models for assessing the effect of toxicants on immunocompetence in mice. Part I: The effect of diphtheria, pertussis, and tetanus vaccine on antibody response to type III pneumococcal polysaccharide.

This study characterizes the response of BALB/c mice to Type III pneumococcal polysaccharides (S3) administered alone or with a vaccine consisting of diphtheria toxoid, pertussis vaccine, and tetanus toxoid (DPT). The usefulness of this vaccine in toxicological protocols for determining immunocompetence is discussed. There were significant differences in antibody titers depending upon the route of injection and whether the S3 was administered in saline or mixed with DPT. Subcutaneous injections induced higher antibody titers to S3 than did intraperitoneal injections. The effect of DPT varied depending upon the manner of administration. Subcutaneous injections of DPT mixed with S3 increased the S3 antibody titers to a dose of 0.1 microgram S3, but had little or no effect at 0.25, 0.5, and 0.75 microgram. Antibody titers were suppressed only at the highest dose administered (1.0 microgram). On the other hand, when administered intraperitoneally DPT has a consistently suppressive effect on 5 day peak S3 antibody titers. Intraperitoneal injections of DPT appeared to delay the rate of antibody induction, since antibody titers at 14 and 21 days were higher in the DPT treated mice than in those animals receiving S3 alone.