Differentiate humoral immunity and cellular immunity as to primary type of lymphocytes (cells) initiated, antigen acted on (or against to what type of pathogens), product of secretion and or mechanism of action of antigen disposal.

Humoral Immunity and Cellular Immunity are two arms of the adaptive immune system that work together to eliminate pathogens. Here's how they differ:

1. Primary Type of Lymphocytes Initiated:

   • Humoral Immunity: This is primarily mediated by B lymphocytes (B cells).
   • Cellular Immunity: This is primarily mediated by T lymphocytes (T cells).

2. Antigen Acted On (or Against What Type of Pathogens):

   • Humoral Immunity: B cells recognize and respond to extracellular pathogens, such as bacteria and viruses that have not yet infected a cell.
   • Cellular Immunity: T cells recognize and respond to intracellular pathogens, such as viruses and bacteria that have infected a cell.

3. Product of Secretion:

   • Humoral Immunity: B cells produce antibodies that circulate in blood plasma and lymph, known as humors, hence the name "humoral". These antibodies bind to pathogens to neutralize them, and mark them for destruction by other immune cells.
   • Cellular Immunity: T cells do not produce antibodies. Instead, cytotoxic T cells produce cytotoxins that cause the death of infected cells. Helper T cells produce cytokines that stimulate other immune cells.

4. Mechanism of Action of Antigen Disposal:

   • Humoral Immunity: Antibodies produced by B cells neutralize, opsonize (mark for destruction), and agglutinate (clump together) pathogens. The pathogens are then destroyed by other immune cells such as phagocytes.
   • Cellular Immunity: Cytotoxic T cells directly kill infected cells by inducing apoptosis (cell death). Helper T cells stimulate other immune cells, including cytotoxic T cells and B cells, to enhance their response to the infection.