Idiotope vaccine against Streptococcus pneumoniae. A precursor study.

An analysis of nominal vs idiotope antigen-induced B cell precursors was performed in A/St mice. With the use of the splenic fragment culture system, the quantity and quality of B cell precursors responding to two anti-idiotope carrier antigens (4C11 hemocyanin and F6 hemocyanin) and nominal antigen (phosphorylcholine-hemocyanin) were compared. In addition, the effect of priming with anti-idiotope-carrier antigens on B cell precursors responding to phosphorylcholine-hemocyanin was determined. We found that one anti-idiotope-carrier antigen, 4C11-hemocyanin, and phosphorylcholine-hemocyanin stimulated similar subpopulations of primary B cells. However, the B cell population stimulated by F6-hemocyanin, the other anti-idiotype complex, was distinct. Furthermore, priming with certain idiotope antigens can direct the phosphorylcholine-hemocyanin response into the expression of idiotypes that may be the most effective in protective immunity. Our results provide essential information for the rational design of idiotype vaccines by clarifying the dynamic relationship of the B cell precursor repertoire with the in vivo antibody response in the response to nominal and idiotope antigens.