Lymph glands and nodes help to

In higher vertebrates,the immune system can distinguish self-cells and non-self. If this property is lost due to genetic abnormality and it attacks self-cells,then it leads to

Identify the cells that form a phagolysosome.

$MALT$ constitutes about what percentage of the lymphoid tissue in the human body (in $, \%$)?

Which substance is produced in a host in response to an infection or a foreign body?

Where are $B$-cells and $T$-cells formed? How do they differ from each other?