Question

The major differences between humoral immunity and cell-mediated immunity is that:
A. humoral immunity is non-specific, whereas cell-mediated immunity is specific for particular antigens.
B. the agents of humoral immunity are carried in the bloodstream, whereas the cells of the latter are concentrated in the lymph nodes.
C. humoral immunity cannot function independently; it always is activated by cell-mediated immunity.
D. humoral immunity acts against free-floating antigens, whereas cell-mediated immunity works against pathogens that have entered body cells.

Answer 1

Hint: The body has a natural tendency to fight against various types of diseases that are produced by the immune system of the body. The immune system helps to fight different types of pathogens and also helps in normal wear and tear.

Complete Solution:
The immune system is a complex network of specific molecules, cells and their interactions to help the body to fight and eradicate the infectious organisms from the body. Our immune system provides protection and resistance towards infectious diseases. The immunity is also known as the self defence mechanism of the body. Immune system or the defence system of the body can be divided into innate immunity and acquired immunity. The innate immunity works on the defence barrier and it is the natural capability of the organism to protect from any disease.

Acquired immunity is the most potent defence mechanism of the body. This is also known as adaptive immunity. They are known for identifying specific pathogens or any foreign materials that are harmful to the body.

The adaptive immunity is of two types which are humoral immunity and cell mediated immunity.

Humoral immunity produces antibodies against the antigens which are found inside infected cells or are free circulating in the blood. It is a type of quick response and is associated with B- Lymphocytes, T- Lymphocytes and macrophages. Humoral immunity shows fast responses against the pathogens that are causing infections to the body.

The cell mediated immunity acts inside the infected cell and it destroys the pathogens or the infectious microorganisms by the process of lysis. They release cytokines. The action of cell mediated immunity is slow and they are associated with T- Lymphocytes, macrophages, helper T cells and natural killer cells. It is generally related to identifying viruses and microorganisms that have invaded the cells of the body.

Therefore, the correct option is option D.

Note: Both the humoral immunity and cell mediated immunity helps to create a defence system of the body against pathogenic diseases that are caused by viruses and microorganisms. The humoral immunity is a fast acting response and acts against free-floating antigens. But the cell mediated immunity acts against the infectious microorganism that invades the cells to cause diseases.