What is the host immune response for the infectious disease: diphtheria?

The usual: The immune system reacts to diptheria as it does to most infections - first w the innate immune response (neutrophils, macrophages) then the cellular response - T cells and B cells (which produce antibodies). Luckily this nasty disease is almost nonexistent in the US because of vaccination, however adults can catch it due to waning immunity. So remember to get your Tdap vaccine as an adult!

Antibody: Your body usually produces protective antibodies with IgM against diphtheria initially then IgG with the latter being longer lasting . However it will takes days for the IgM to be produced and thus you will still be sick when infected (unless previously exposed or immunized) although you will have some protection against getting infected again for a decade or more after.