Identify the false statements.

1. Heat inactivation of serum is done to inactivate prions.
2. Nude mice refer to transgenic mice.
3. A humanised antibody is one in which the CDRs are from mouse and the rest is from human.
4. B-lymphocytes originate from the bone marrow.

Correct answer. Both are false statements. Heat-inactivation (heating to 56°C for 30 minutes) of serum is done to inactivate complement, a group of proteins present in sera that are part of the immune response. A nude mouse is a laboratory mouse from a strain with a genetic mutation that causes a deteriorated or absent thymus, resulting in an inhibited immune system due to a greatly reduced number of T cells.