FURTHER-STUDIES ON IMMUNOLOGY OF INFANT RAT EXPERIMENTAL-MODEL OF HEMOPHILUS-INFLUENZAE TYPE-B MENINGITIS

Google Scholar
  • 1 January 1978
    • journal article
    • research article
    • Vol. 59  (5) , 544-550
Abstract
An age-related acquisition of anti-capsular (AC) antibodies [Ab] to H. influenzae b(HIb) did not occur in rats; this result corrects a previous spurious observation from this laboratory. Purified HIb polysaccharide was totally non-immunogenic over a wide range of doses in infant and adult rats, with or without booster immunizations. Killed HIb was totally non-immunogenic. Only about 1/4 of survivors of infantile HIb disease made an AC Ab response. In an attempt to observe immune paralysis, survivors of infantile HIb disease were immunized with live HIb at age 8 wk. This immunization resulted in significantly fewer AC AB responders in the survivors than in the controls. Immunization of survivors with killed HIb produced significantly greater responders in survivors than in controls. To determine whether passive protection from HIb disease could be achieved by non-capsular Ab, survivors'' offspring were protected from infantile HIb disease due to bactericidal (BA) Ab that were probably not directed at the capsular polysaccharide. Using the BA assay, differences were observed between 2 HIb strains, presumably due to differences in non-capsular antigens [Ag]. The infant rat experimental model of HIb disease appears to have only limited value in the study of AC Ab responses since infant rats differ from infant humans in several respects. The model may be more useful in studying the immunology of non-capsular HIb Ag including their role in protective immunity and possible differences in these Ag among strains of HIb.