Humoral immunity is due to

The protein that possesses the property of immunity is .........

Regarding kidney transplantation,four statements are given below. Select the correct statements.
$i.$ During kidney transplantation,the recipient's immune system is suppressed for a long time.
$ii.$ Cell-mediated immunity is responsible for the rejection of the transplant.
$iii.$ $B$-lymphocytes are responsible for the rejection of the transplant.
$iv.$ Specific interferons are responsible for the acceptance or rejection of the kidney transplant.
Select the correct option:

What are $IgA$ and $IgE$?

The principle of vaccination is based on which property of the immune system?

The antigen-binding site in an antibody is found between: