Enhancement of immunogenic activity of ribosomal preparations from Haemophilus influenzae by various adjuvants

Ribosomes from Haemophilus influenzae type b have been reported to have immunoprotective activity in animals that can be enhanced by adjuvants. In this report we evaluated the adjuvant activity of several compounds in conjunction with ribosomes from the b and c serotypes of H. influenzae. Alhydrogel, saponin, and DPT were found to significantly enhance the immunoprotective response in mice, equalling or exceeding the activity of Freund's incomplete adjuvant. All of these adjuvants also enhanced significantly the IgM response of mice to sheep red blood cells. Ribosomes were also found to enhance this response. Among the compounds failing to provide adjuvant activity for ribosomes were poly(A:U), muramyl dipeptide, mycobacterial extract, dimethylglycine, methylated bovine serum albumin, sodium diethylthiocarbamate, and cetyltrimethylammonium bromide.