Modulation of the murine immune response to streptococcal group A carbohydrate by immunization with monoclonal anti-idiotope.

Using monoclonal anti-idiotopes with previously defined specificities for the variable (V) domain of HGAC 39, a monoclonal antibody against streptococcal group A carbohydrate (GAC), we have studied the effect of anti-idiotope on an anticarbohydrate immune response. Anti-IdI-3a and anti-IdI-3b are anti-idiotopes which recognize binding site-associated determinants, whereas anti-IdX recognizes a framework-associated determinant on the HGAC 39 V kappa domain. Each of three anti-idiotopes elicited a specific idiotope response, as measured by inhibition radioimmunoassay, in A/J and C57BL/6J mice. A single immunization with conjugated anti-IdI-3a elicited an idiotope(+), GAC-binding(+) response in C57BL/6J and (BALB/c X CBA/N)F1 male mice, but not in A/J or (CBA/N X BALB/c)F1 male, X-linked immunodeficient mice. When C57BL/6J mice immunized initially with anti-idiotope were further treated with group A vaccine, those receiving anti-IdX had the greatest increase in anti-GAC activity. Stimulation of an anticarbohydrate response with anti-idiotope may therefore be enhanced by selecting anti-idiotopes against both binding site- and framework-associated determinants.