Question

An individual finds himself infected by a previously undiscovered pathogen, Transmissio (this is what my teacher put)

What is the body’s initial response? What are the long term effects?-be detailed

Answer 1

The acquired active immunity happens when a person is infected by a pathogen. Active immunity is a type of immunity in which antibodies are produced by the immune system in response to the foreign antigen. Active immunity lasts for a longer period of time.

The acquired immunity is primarily dependent on the action of the lymphocytes, B cells, or T cells. B cells and T cells have antigen receptors on their surface which are antigen-specific. Specific receptors are present on each lymphocyte. The immune responses of B-cells and T-cells after the infection are explained below.

The defense provided by the B cells is known as antibody-mediated immunity because the activated B cells become plasma cells that form antibodies. It is also known as humoral immunity because the antibodies are found in the lymph or blood.

The B cells activate in the spleen or a lymph node when the specific antigen binds to its specific B-cell receptor (BCR). The B cells undergo clonal expansion and divide by mitosis several times soon after antigen binds to its BCR. B cells form many copies of itself and most of the clones transform into or become plasma cells, that circulate in the lymph and the blood.

Few cloned cells are transformed into memory cells which are critically important for long-term immunity. The second exposure of any antigen results in the quick division of the memory B cells that further give rise to more plasma cells that have the ability to produce the correct antibody rapidly.

The plasma cells are greater than regular B cells because of the presence of an extensive network of RER (rough endoplasmic reticulum) for the production and secretion of the antibodies to a particular antigen on a larger scale.

Therefore, B cells generate the plasma cells that produce the antibodies which combine with a particular antigen and neutralize it.

A primary response is generated after the first exposure to a foreign antigen (pathogen). For a few days, antibodies are not present, then there is a rise in the antibodies. A secondary response is generated after the second exposure to the pathogen. The immune response is extremely high at the time of the second exposure, thus, the second exposure is also called a booster. The disease symptoms are prevented even after the exposure of the individual to the disease-causing agent because the antibodies and the antigen-specific T cells are extremely high for a longer period of time in active immunity after the second exposure.