Abstract
The genetic polymorphism in early, immunoglobulin M, responsiveness to the Klebsiella pneumoniae type 47 polysaccharide (K47-PS) is determinant specific, and L-rhamnose is probably the determinant against which differential responsiveness is expressed. This is inferred from tests of the response to the cross-reacting Streptococcus pneumoniae type 23 and non-cross-reacting pneumococcal polysaccharides of known chemical construction. B10.2/Sn new-line mice are high responders and BALB/c mice are low responders to K47-PS. Upon immunization with killed S. pneumoniae type 23, these strains produce cross-reacting antibody to K47-PS. The cross-reacting antibody responses of these strains are congruent with their responses to K47-PS.