or cellular immunity, occur through the T-cell system. On exposure to an antigen, the lymphoid tissues release large numbers of activated T cells into the lymph system. These T cells pass into the general circulation. There are three main groups of T cells: (a) helper. (b) cytotoxic T cells: which attack and kill microorganisms and sometimes the body's own cells.
Organ Donation Day. About Organ Donation Day. Organ Donation Day in India is celebrated on 13th of August every year by the people, government organizations and other related professions in order to motivate normal human beings to donate the organs as well as to understand the value of organ donation in the life of an individual.
The Sound and Fury of Philadelphiaâs Wanamaker Organ. Get blown away listening to the largest operating pipe organ in the world. Philadelphia is known as the birthplace of independence and gooey cheesesteaks, but for some, the Wanamaker Organ defines the City of Brotherly Love. The 111-year-old organ at Macyâs Center City Philadelphia is a sight to behold: Seven stories tall, weighing 287 tons and containing 28,750 pipes, it's the worldâs largest playable instrument.