Perforins are produced by
A. Cytotoxic T cellsB. Suppressor T cells
C. Memory helper T cells
D. Plasma cells
E. NK cells
The Answer is. (A) Cytotoxic T cells
• Perforins, are hole
forming proteins synthesised by Cytotoxic
T-cells.
• Cytotoxic T-cell kill
micro-organism, directly attacking cell so called Killer cells. The receptor
proteins on surface of cytotoxic cells cause binding tightly to those organism
or cells that contain their binding specific antigen. After binding, T cells
secrete performs which punch large round holes in the membrane of attacked
cell. The released cytotoxins from cytotoxic T-cell attack the cell.
• Suppressor T-cells—suppress the
functions of both cytotoxic and helper T-cells. They are responsible for immune
tolerance. They are classified as regulatory T-cells.
• The Memory cells are that have ben
exposed to antigen and aireadily converted to effector cells by later encounter
with the same antige. There is accelerated response to the second exposure.
Memory cells are long lived.
• Plasma cells secrete immunoglobulins.
• NK cells Mediate natural immunity, are special
population of large lymphocytes, have role in immunity against tumour and
transplant cells, mediate action through complements. Cells die of osmotic
lysis or apoptosis.
• Granzyme: induces apoptosis in the
virus infected cells. Secreated by the cytotoxic T cells
