This study was performed in female B6C3F1 mice to confirm previously observed effects of selected cephalosporin antibiotics on nonspecific immunity, and to determine possible effects on specific acquired immunity and host resistance. Mice were treated intravenously with DQ-2556, ceftizoxime or ceftezole at 800 mg/kg/day for 3, 5, or 7 consecutive days. All three compounds increased total serum IgM levels from day 3, but had no effects on total serum IgG levels and the thymus weight. All three cephalosporin antibiotics caused a slight increase in spleen weight and splenic germinal centers were enlarged after 5- or 7-day treatments. Antibody responses to type III pneumococcal polysaccharide (S3), a T-cell-independent immunogen, and sheep red blood cells (SRBC), a T-cell-dependent immunogen, were slightly decreased after 5-day dosings with each compound, and reached significance in DQ-2556 (response to S3) and ceftizoxime (response to S3 and SRBC). None of the tested cephalosporin antibiotics altered delayed-type hypersensitivity to oxazolone or host resistance to Plasmodium yoelii, indicating that the antibiotic-treated mice retained the capacity to mount a multicomponent and sustained protective immune response. These data suggest that although cephalosporins may cause polyclonal expansion of B cells with associated increases in total serum IgM, they do not affect the tested measures of cell-mediated immunity or host resistance. The decreased IgM antibody responses to S3 and SRBC are associated with but not known to be causally related to the concurrent IgM hypergammaglobulinemia.

Animals↗

PubMedDate not supplied

Hot-air ballooning injuries.

The sport of hot-air ballooning is generally safe, but does place its participants in certain unique circumstances which may predispose them to injury. Fractures of the ankle and compression fractures of the lumbar spine are among the most common skeletal injuries that require orthopaedic care. Attention to basket design, proper education of the passenger, and careful consideration of terrain and prevailing weather conditions may help make ballooning a safer sport.

Adult↗

PubMedDate not supplied

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.

Animals↗

PubMedDate not supplied

Models for assessing the effect of toxicants on immunocompetence in mice. II. Effect of cyclophosphamide on the antibody responses to type III pneumococcal polysaccharide and tetanus toxoid in BALB/c female mice.

A mixture of antigens was used to detect alterations in immunocompetence. Type III pneumococcal polysaccharide (S3) and tetanus toxoid (TT) stimulate different cellular components, and can therefore be used to assess different compartments of the immune mechanism. Cyclophosphamide (CP), a known immunosuppressant, had a potent effect upon the antibody responses to both S3 and tetanus toxoid. All doses of CP administered within 2 days of priming with S3 resulted in a dose-related immunosuppressive action which persisted even after reinjection of S3. 300 mg/kg of CP given up to 14 days prior to or following primary immunization resulted in a marked suppression of antibodies to S3. Doses of S3 which were partially tolerogenic were made even more so by injections of CP. The effect persisted over a 96 day experimental period. CP also suppressed the formation a memory cells necessary for induction of a secondary-type IgG response to TT. The time of injection for maximum suppression was days 10 to 14 after priming. Therefore, the suppression must involve cellular mechanisms different from those responsible for S3 antibody suppression. In addition, there was a difference in the degree and persistence of the suppressive effect, since the suppressed animals were able to mount an immune response to subsequent injections of TT. Double injections of a high dose (300 mg/kg) of CP 4 weeks after priming completely suppressed the acquired immunity to both S3 and TT. Low and moderate doses of CP appeared to induce a mild augmentation of S3 antibody response when given 4 weeks after priming. However, an immunosuppressive effect occurred if the primed animals were reinjected with S3 or challenged with TT within a period of 2 days prior to or after receiving the CP treatment. Doses of CP, injected prior to challenge and resulting in suppressed tetanus antitoxin production, elevated the titers of specific IgE antibody. This class of antibody is associated with adverse hypersensitivity reactions. These data provided background for the development of models to assess immunocompetence in mice, based on a study of immune profiles following exposure to selected T-dependent and T-independent antigens. Such models may be used to detect potentially hazardous chemicals found in the environment of incorporated into foods, drugs, or cosmetics.

Animals↗