Humoral response is a third line of defence, not 2nd. By 'cellular response', do you mean 'cell-mediated response'? That's also a third line of defence. J_Rho is right in saying that it depends on the infection, typically on whether it's bacterial (typically humoral, but could be a intracellular parasite) or viral (cell-mediated).
MHC1 proteins and markers are the same thing, but I'd probably stick with markers instead.
By 'cellular response', I mean phagocytes and antigen presenting cells, so the 2nd line of defence. And by "humoral response", I mean complement proteins, cytokines, inflammation and fever, so in the 2nd line of defence also. There are cellular and humoral responses in the 3rd line of defence too, but they're different. And thanks for the clarification about the MHCs markers!!
The cellular response of the innate immune system can consist of phagocytes and antigen presenting cells. phagocytes can quickly eliminate PATHOGENS by engulfing them and breaking them down with digestive enzymes, and then releasing them out. but in another process, phagocytosis of an ANTIGEN occurs, except it is followed by an class II MHC protein binding onto one of the fragments of the antigen and presenting it to a helper T cell......... how come the phagocytosis of a pathogen (first process i mentioned), doesn't involve MHC proteins? or similarly, why can't the second process not involve MHC proteins?
Mod Edit: Merged Double Posts