Question

Name the major cells of the immune system. Give a detailed account of their response to an antigen attacking humans.

Answer 1

Hint: The composition of blood is RBC, WBC, Platelets and plasma. The immune system is formed by all the components of the white blood cells. The other cells do not play any part in immunity and only WBC contains specific cells for immune actions.

Complete answer:
The responsibility of providing immunity to the body is given to the white blood cells. The white blood cells are composed of the B-cells, T-cells, Nk Cells, neutrophils, and monocytes which are also known as the macrophages. Now let’s discuss the separate functions of each cell.
Whenever any antigen enters into the body b cells are first to come into action, the b cells go and interact with the antigen and after analyzing the antigen, the b cells prepare a set of proteins known as the immunoglobulins which counteract the invasive antigen which has entered. This type of immune response is called an adaptive humoral immune response.
On the other hand, the t cells are responsible for the direct killing of the antigens and it does not wait and analyze the type of antigen instead it provides an adaptive response if the body has encountered that antigen before. T cells not only kill the antigen instead they also help in activating other immune cells by releasing a set of chemicals namely cytokines.
Nk cells are responsible for the killing of antigen, basically viruses. This is achieved by them by their ability to distinguish between the affected cell and the unaffected cell. This type of response is known as the innate immune response.
Neutrophils help in the destruction of the pathogen on its very first phase of entry into the body. Also, the cytokines released by the t cells are acting upon these neutrophils and thus generating the immune response.
Monocytes, also known as the macrophages are the cells which are responsible for the phagocytosis of the antigen cells, and after the phagocytosis, these cells present antigen in such a way that the body van prepare antibodies against this antigen in such a way that if this antigen enters again so the body can kill it easily.

Note:
The platelets cannot be involved in the process of the immune response because the platelets come into action whenever there is a bodily injury and it prevents blood loss and it does not have any function in providing cellular responses.