Structural and genetic basis of the in vivo immune response to TNP-LPS.

TNP-lipopolysaccharide (TNP-LPS) is a potent T-independent antigen in vivo, inducing a TNP-PFC response in T-depleted animals. The structural integrity of the lipid A-KDO portion of the LPS carrier molecule appears to be required since the haptenated LPS from Salmonella minnesota Re595 is immunogenic whereas the haptenated derivative of base hydrolyzed LPS is not. The immune response is not associated with any of the common histocompatiblity types, but does depend on the ability of the host strain to respond to LPS. C3H/HeJ mice are not killed by low doses of LPS and give a poor PFC response to TNP-LPS. Lethality and immunogenicity are dominant responses in hybrids of C3H/HeJ and responder mice. The structural and genetic requirements for the response to TNP-LPS suggest an active role for the carrier in the immunogenicity of this T-independent antigen.