Further Studies of the Polysaccharide of Klebsiella pneumoniae Possessing Strong Adjuvanticity: III. Augmentation of the Antibody Response to Subcutaneously Injected Sheep Red Blood Cells by the Adjuvant Polysaccharide

Abstract

The adjuvant action of the 03 antigen of Klebsiella (K03) on the antibody response to sheep red blood cells (SRBC) was elucidated by injecting both K03 and SRBC subcutaneously at the right inguinal region of SMA mice. We demonstrated that K03 exhibits a novel ability to augment anti-SRBC plaqueforming cell responses in both the local lymph node and the spleen at a relatively late stage of immunization. Escherichia coli lipopolysaccharide, dextran sulfate and concanavalin A showed such an action only minimally. In parallel with the development of the adjuvant action, K03 definitely activated B cells in the local lymph node polyclonally for either IgM or IgG synthesis, suggesting that the mechanism of the adjuvant action includes direct stimulation of B cells by K03 at the late stage. Neither increase in trapping of lymphocytes in the local lymph node nor change in tissue distribution of antigen was shown to be primarily involved in the mechanism of the adjuvant action.We have reported that the polysaccharide extracted from the culture supernatant of Klebsiella pneumoniae type 1 strain Kasuya (03:Kl), formerly designated CPS-K or neutral 21) and recently shown to be serologically identical to the 03 antigen of Klebsiella (K03) (14), exhibits a strong adjuvant action on antibody responses (17,18,21) and on induction of delayed-type hypersensitivity (30) to soluble protein antigens including saline extracts of syngeneic tissues (17,20) when injected subcutaneously (sc) together with the antigens. This action of K03 was much stronger than that of Escherichia coli lipopolysaccharide (LPS), dextran sulfate (DS), polyadenylic-uridylic acid, concanavalin A (Con A), and Freund's complete adjuvant (17,28). On the other hand, K03 did not augment antibody responses more strongly than did E. coli LPS when injected intravenously (iv) to-843

Retention of bacterial lipopolysaccharide at the site of subcutaneous injection

“…Since there was no marked difference in the retention patterns of various kinds of LPS, it is difficult to speculate on the particular association of retention of K03 LPS at the injection site with its extraordinary strong adjuvant action. However, retention of K03 LPS at the site can easily explain the following characteristic phenomena at the regional lymph node: (i) K03 LPS exhibits a novel adjuvant action on plaque-forming cell response to s.c. injected sheep erythrocytes which develops at a late stage of immunization (7 to 14 days) (29); (ii) major polyclonal activation of B cells develops at a late stage in the regional lymph node after s.c. stimulation with K03 LPS alone (at 5 to 11 days) (29); and (iii) marked proliferation of macrophages and their precursors can be seen in the regional lymph node at a late stage (7 to 10 days) (27,28). Probably the main cause for these phenomena is that K03 LPS remaining at the local site continuously stimulates B cells and macrophage lineage cells at the draining lymph node.…”

“…The potent adjuvant action of K03 LPS was much greater than that of Freund complete adjuvant or LPS from Escherichia coli, other Klebsiella spp., and Sallmonella spp. (12,14,29), and severe autoimmune lesions were produced in the respective organs when mice were immunized subcutaneously (s.c.) with the syngeneic tissue antigens together with K03 LPS (15,19,30). Its strong adjuvant action was seen only when antigens were injected s.c. together with K03 LPS, and the strength of the adjuvant effect of K03 LPS when injected intraperitoneally (i.p.)…”