• Vaccination only refers to the administration of a
vaccine or toxoid, while immunisation is the process
by which the body produces antibodies against the
vaccine preventable diseases through administration
of specific vaccines.
• Different types of vaccines are listed in the following
flowchart.
orgAn trAnspLAnt
• Transplantation involves the removal of damaged/
injured tissues or organs from the body of a person
and their substitution by similar tissues/organs from
a donor.
• It may result in the rejection of transplanted organs
or tissues (graft rejection) as the immune system
recognizes the protein in the transplanted tissue or
organs as foreign, and initiates cellular immunity.
• Cytotoxic T cells and helper T cells are mainly
responsible for graft rejection.
• Class I MHC proteins on the cells of a graft differ from
the recipient’s as do the class II molecules present on
the macrophages in the graft.
• Consequently, the MHC proteins of both classes are
recognised as foreign by the recipient’s T cells.• The cells bearing these proteins are destroyed by
recipient’s cytotoxic T cells with the aid of helper T
cells.