To confirm that CD4 T cell reactivity to H. pylori ferritin was due to HA-Fe-nanoparticle immunization and not murine Helicobacter infection, splenocytes of naïve CBA/J mice were tested for reactivity to immunodominant ferritin peptides by cytokine ELISpot and compared to HA-nanoparticle immunized controls. The gene discussed is CD4; the disease is Helicobacter pylori infectious disease.