Immunoglobulin isotype in the murine response to polysaccharide antigens

Murine antisera specific for the α (1→3) and α (1→6)-linked glucosyl determinants of dextran, as well as for meningococcal polysaccharide group C, have been examined for the distribution of their immunoglobulin classes and subclasses. Whereas the thymus-independent anti-α (1→3) dextran response in BALB/c mice was found to be IgM > IgG₃ > IgA, thus corresponding to previously published work, neither the α (1→6) response in its thymus-dependent or-independent form, nor the response to purified meningococcal polysaccharide, corresponded to this pattern. No preference for any of the IgG subclasses appeared for these antigens when given as thymus-independent carbohydrates. On the other hand, thymus-dependent forms of α (1→6) dextran showed an IgG₁ > IgG₃ > IgG₂ pattern.