some metals are but the body spits it out so to speak but titanium can go in and not get "spit out" other things like parasites like hook worms, viruses and mostly organisims!
They are attacked by lymphocytes.
Leukocytes
Antigens Antibodies neutralize these molecules.
White Blood Cells(Leucocytes). They engulf the foreign(harmful) substances in the body through enzymes.
The skin is your body's first defense in fighting infections and foreign substances. Your digestive system is your next defense.
Foreign substances would suffice as well as contaminants, toxins, etc.
antigens
Antigens is the term for molecules that are foreign to the body.
Immune system
To rid your body of foreign substances in your nose,
antibodies
The body's defense system is the immune system.
no
immunology
T-cellls
The Immune System is the defense network of the body. The immune system works with specific receptors on specialized cells - detecting foreign bodies and signaling for the immune system to destroy them.
Immune System, bud.