AbstractMurine 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 sho