What can be included in $CMI$?

The lymphocytes provide the principal defence mechanism by producing

Identify the correct statements from the following:
$(i)$ The skin is the main physical barrier.
$(ii)$ Mucus coating of the epithelium lining the respiratory,gastrointestinal,and urogenital tracts is a physiological barrier.
$(iii)$ $IgA, IgM, IgE, IgG$ are types of $T$-cells.
$(iv)$ The primary immune response is very intense.

Which type$(s)$ of interferon is/are present in humans?

Immunodeficiency makes a person highly susceptible to infection. It is caused by

Following are functions of free antibodies circulating through body fluids $EXCEPT$ . . . . . . .