What is the difference between ami and cmi

Generate responses to eliminate specific pathogens or pathogen-infected cells. Development of immunological cells. In this topic, we will further discuss humoral immunity and cell-mediated immunity.

Humoral immune activity is one of the mechanisms of the active immune system and is associated with circulating antibodies in contrast to cellular immunity. The wide range antibody activities is a response to rapid production of antigen-specific B cells during infections which increases antibody titres with enhanced affinity for the inciting agent and more directed and effective response.

Cell-mediated immunity is a type of adaptive immune response that does not involve antibodies but it does involve the activation of NK cell and macrophages and the production of antigen-specific cytotoxic T-lymphocytes and the release of several cytokines in response to a foreign antigen. Cell-mediated immunity plays an important role in controlling viral, chlamydia, rickettsia and protozoan infections such as trypanosomes as antibodies cannot penetrate and attack intracellular pathogens which multiply within the host cells.

The humoral immune system starts with the production of proactive antibodies against infection or reinfection by common microorganisms such as staphylococci and streptococci.

B- Lymphocytes, which have specific antigen receptors react when they come to contact with the specific antigen by producing plasma cells. These plasma cells produce antigen-specific antibodies and memory cells which enable the body to rapidly produce antibodies if the same antigen appears later.

Antibodies which are produced by plasma B-cells are found mainly in the blood spleen and lymph nodes and they eliminate antigens in several ways. Some of them are, by activating the complement system and neutralising viruses and bacterial toxins. Another method is by coating the antigen by opsonization or forming an antigen-antibody complex to stimulate phagocytosis which promotes antigen clumping and prevents antigens from attaching to host cells. The mechanism of cell-mediated immunity takes a different approach than humoral immunity.

This mechanism protects the body through the following activities:. The response starts by activating antigen-specific cytotoxic T-lymphocytes or CTLs which can destroy body cells which show epitopes of foreign antigen on their surfaces such as cells with intracellular bacteria, cancer cells which show tumour antigens and virus-infected cells. It also activates NK cells and macrophages which enable them to destroy intracellular pathogens. The response stimulates the cells to produce a wide range of cytokines that regulates the function of other cells involved in adaptive immune responses and innate immune responses.

Cell-mediated immunity is directed primarily towards microbes which survive phagocytes and microbes that infect non-phagocytic cells. It also plays a major role in delayed transplant rejection. There are various differences between humoral immunity and cell-mediated immunity and we will discuss them below. Humoral Immunity. Cell-Mediated Immunity. Humoral immunity is mediated by macromolecules which are found in extracellular body fluids. This type of immunity is mediated by the T-lymphocytes, NK cells and other immune system cells of the body.

B-cells are involved in humoral immunity. T-cells are the primary mediators of Cell-mediated immunity. The components include macrophages, B-cells and T-cells. The components include T cells, cytotoxic T-cells, NK cells and macrophages. Humoral immunity protects the body against extracellular pathogens and their toxins. Cell-mediated immunity protects the body against intracellular pathogens.

Pathogen recognition. Recognises pathogens in circulating in blood or lymph. It responds to any cell that displays aberrant MHC markers which include cells invaded by pathogens, transplanted cells or tumour cells. Antigen detectors. Antibodies and phagocytes are used to detect antigens. MHC molecules on the cell surface and receptors are used to detect antigens. Antigen binding. Antigens are not processed. Antigens are processed and presented for T-Lymphocyte response. Receptor involved. B-cell receptors are involved.

T-cell receptors are involved. Integrins, CD3 molecular complex. T-cell involved. Basis for Comparison Humoral Immunity Cell-Mediated Immunity Meaning The humoral immunity is associated with the B-lymphocytes and is responsible for destroying the pathogens by producing antibodies against it.

The cell-mediated immunity is associated with the T-lymphocytes and is responsible for destroying the pathogens or microorganism which have invaded the cells. Mediated by Humoral immunity is intimately associated with B-lymphocytes, T-lymphocytes and macrophages.

These are associated with T-lymphocytes, helper T cells, natural killer cells and macrophages. Antibodies Present. Function 1. It plays a major role in recognizing antigen or any foreign particle and in producing antibodies against it. Humoral immunity is known for working against extracellular pathogens. Cell-mediated immunity is related to T-lymphocytes, which work by identifying viruses and microorganisms,thus destroying them by the cell lysis or phagocytosis or pinocytosis.

It is known for working against intracellular pathogens. Secretes It secrets antibodies. It secretes cytokines.

Action against pathogen Humoral immunity is rapid or quick in their response. The Cell-mediated immunity show delay though permanent action against any pathogens.

Cell-mediated is the delayed in response and mediates hypersensitivity type IV. Rejections Humoral immunity is involved in the early stage of graft rejections due to the formation of antibodies. Cell-mediated immunity is involved in the rejection of organ transplants. Humoral immune response or antibody-mediated response is associated with the B cells, where the role of these cells B cells is to identify the antigens or any foreign particle that are present in the circulation in blood or lymph.

This immune response is also assisted with helper T cells which along with the B cells get differentiated into plasma B cells that can produce antibodies. As soon as B cells produce antibodies, they will bind to an antigen; neutralize them and causes phagocytosis or cell lysis destruction of the cells.

The antigen is the foreign particle, which is usually a carbohydrate or a protein that triggers an immune response, but above that our body has tremendous capability to identify the antigens. Any kind exposure of antigens leads to the development of secondary immunological response which increases the level of the immune response.

The immunoglobulins or antibodies mediate the humoral immunity, these are a particular group of proteins produced by the B-lymphocytes. T lymphocytes assist the Cell-mediated immunity or cellular immunity. In this type, cytokines have released that help to activate the T cells which further destroys the infected cell.

Likewise the B cells, T cells originate in bone marrow but matures in the thymus and later gets circulate in the bloodstream and lymphoid tissue. Abnormal or aberrant MHC molecules are formed from the antigens which have been destroyed or broken down or from any infected virus exogenous antigens or the from tumour cells that are actively producing foreign proteins endogenous antigens.

Now helper T-cells release the cytokines, that will activate the T cells, which will recognize the aberrant MHC-antigen complex and will bind to it and differentiate into cytotoxic T cell. After this cell will undergo lysis cell destruction.