Difference Between Humoral and Cellular Immunity

Humoral Vs Cellular immunity

The difference between humoral and cell-mediated immunity are mainly due to two factors like the type of an immune response and the Regulation of immunity.

Type of Immune response: Humoral immunity produces an antibody-mediated immune response whereas cellular immunity produces a cell-mediated immune response.
Regulation of Immunity: B cell mainly regulates the humoral immunity whereas T cell regulates the cellular immunity.

Content: Humoral Vs Cellular Immunity

  1. Comparison Chart
  2. Definition
  3. Difference in mechanisms
  4. Important terms in Humoral immunity
  5. Important terms in Cellular immunity
  6. Similarities
  7. Key Differences
  8. Conclusion

Comparison Chart

PropertiesHumoral immunityCellular immunity
DefinitionIt is kind of adaptive immunity that produces antigen specific antibodies to destroy the antigensIt is a kind of adaptive immunity that produces antigen specific T-cells to destroy the antigens
Type of immunityAntibody-mediated immunityCell-mediated immunity
Major roleB-lymphocyte cellT-lymphocyte cell
Antibody formationOccursDoes not occur
Cells involvedB-cell, plasma cell, T-cell, macrophagesTH , TC , NK, macrophage, dendritic cells
Action against pathogenDestroys the extracellular pathogensDestroys the intracellular pathogens
ReceptorsIt involves BCR receptorsIt involves TCR receptors
Accessory surface moleculesIgα, Igβ, CD40, cd21 and FcCD2, CD3, CD4, CD8, CD28 and integrins
Efficiency of immune responseRapidComparatively slow
Involvement of tumour cellsIt can’t eliminate tumour cellsIt eliminates the tumor cells thus provides immunity against cancer
HypersensitivityIt involves immediate hypersensitivity (Type-I, II and III)It involves delayed hypersensitivity (Type- IV)
Target pathogenExtracellular bacteria and virusesIntracellular bacteria, fungi and viruses
ResultIt results into the formation of antibodies by the Plasma cellsIt results into the formation of cytokines by the T-cell

Definition

Humoral immunity:
Humour means body fluids (like blood and lymph) and Immunity means protection which can define as the active immunity in which the antigen-specific antibodies are produced by the B-cells in the body fluids where they first bind and neutralizes all the extracellular pathogens.

Cellular immunity:
As from the name it is clear that this type of immunity is mediated by a cell so it can define as the active immunity in which the antigen-specific T-cells are produced by the thymus which secretes cytokines to destroy all the intracellular pathogens.

Difference in mechanisms

Humoral immunity: It involves the following steps:

humoral immunity

  1. Firstly, the immature stem cells produce B-cells which then move towards the lymphoid organs.
  2. Then, recognition of the antigen takes place with the help of BCR i.e. B-cell Receptors.
  3. Then the B-cell engulfs the antigen by the process of “Endocytosis” by forming a phagolytic vesicle around the antigen.
  4. After that, the intracellular enzyme (Lysozome) fuses with the phagolytic vesicle by forming “Phagolysozome”.
  5. Then this complex “Phagolysozome” digests the pathogen and breaks the antigenic fragments.
  6. The antigenic fragments are displayed to the MHC (Major Histocompatibility Complex), which activates the T-cell.
  7. Then the differentiation of B-cells into the mature plasma cells occurs with the cooperation of T-cells.
  8. Division of plasma cell occurs which divides to produce its own clones.
  9. Then the clones of plasma-cell will produce antibodies specific to the particular antigen. And, the antibodies will bind and neutralize the antigenic properties of the extracellular pathogens.

Cell-mediated immunity: It involves the following steps:

Cellular immunity

  1. First, the digestion of antigen occurs by the dendritic cell or macrophages. Then the processing of antigen is carried out via MHC.
  2. Then the T-cell gets activated by the MHC-Antigen complex and starts secreting “Cytokines”.
  3. The cytokines produced by the T-cell will produce mature T-cells which undergo differentiation and forms many types of T-cells.
    • Cytotoxic T-cell destroys the cells displaying the antigen.
    • Helper T-cell releases interleukins that stimulate the production of B-cells to produce antibodies which then binds with the antigen by stimulating natural killer cells and macrophages.
    • Suppressor T-cell functions to maintain immunological tolerance by inhibiting the activity of other lymphocytes like B and T-cells.
    • Memory T-cell remember the site of infection or the infected cell for the future encounter

Important terms in Humoral immunity

  • B-cell: It also refers to B-lymphocytes which are the types of WBC. B-cells are released by the stem-cell in the bone marrow. The maturation of B-cell occurs in the bone marrow where it differentiates into the plasma cells. B-cell is having a short life span and it is “Thymus-independent”.

B-lymphocyte

  • Plasma-cell: It forms by the maturation of the B-cell.  Plasma-cell undergoes cell-division by producing many antibodies in the body fluid. The tendency of plasma cells to produce antibodies is 2,000 antibodies per second.

plasma cell

  • Endocytosis: It is the process of entrapment of molecule which is taken into the cell and forms a vesicle around that molecule.

endocytosis

  • MHC: It stands for “Major Histocompatibility Complex”. These are the transport proteins that surrounds on the surface of almost all the immune cells which performs a key role in the processing of antigen, it also helps the T-cells to distinguish between the self and foreign antigens. Class-I MHC and Class-II MHC are the two common types of major histocompatibility complex.

MHC

Important terms in Cellular immunity

  • APCs: It stands for “Antigen Presenting Centres”. These are the types of cell which first recognizes the foreign body, then engulfs it through endocytosis and form vesicle around the antigen. Then these APCs phagocytose the antigens and digests it by forming many fragments which are then loaded on the MHC by activating the T-cell via MHC antigen processing. These are of three types namely dendritic cells, Macrophages and B-cells.

ANTIGEN PRESENTING CELL

  • T-cell: In T-cell, T stands for “Thymus” which is also a type of WBC that performs a significant role in the immune system. This cell produces in the thymus from the thrombocytes.

T-cell

T-cell produces more cytokines and undergoes differentiation into many effective T-cells where each performs a distinct function. There are the following types of T-cells which include:

Helper T-cells: It assists the other cells in the immunological processes and refers as CD4+ T cells because they can express the CD4 glycoprotein on their surface. It can also release interleukins that can stimulate the production of B-cells, (NK-cells) Natural killer cells, Macrophages to destroy the antigens.

Cytotoxic T-cells: It also refers to ac Tc cells, killer T-cells and CD8+ T-cell  (expresses CD8 glycoprotein at their surface). It directly destroys the antigen infected cell mainly virus infected.

Suppressor T-cells: It also refers as “Regulatory T-cells” which inhibits T and B-cells.

Memory T-cells: It recognizes the pathogen for the future encounter or for the second exposure.

Similarities Between Humoral and Cellular Immunity

  1. Humoral and cell-mediated immunity both generates an antigen-specific immune response.
  2. Both humoral and cell-mediated immunity are specific in their action where one produces an antigen-specific antibodies and the other produce antigen-specific T-cells.
  3. The immunization of both the kind of immunity (humoral and cellular) is an Active immunization type.
  4. The objective of both humoral and cellular immunity is the same, that is to protect the immune system from the foreign body.

Key Differences Between Humoral and Cellular Immunity

  1. Humoral and cellular both are the adaptive immunity where B-cells produce antibodies against an antigen and the other produce T-cells which secretes cytokines to attack the antigen infected cell.
  2. B-lymphocyte and T-lymphocyte plays an important role in humoral and cellular immunity to provide immunity against an antigen.
  3.  Humoral immunity is antibody-mediated because here the antibodies bind with antigens that are present in the body fluid and helps to neutralize them. Cellular immunity is mediated by the T-cells which produce more cytokines to destroy the antigen infected cell.
  4. In humoral immunity, the plasma cell produces antibodies whereas, there is no such production in cellular immunity.
  5. Extracellular pathogens are processed by the humoral immunity whereas Intracellular pathogens are processed by cellular immunity.
  6. B-cell receptor involves humoral immunity whereas T-cell receptor involves in cellular immunity.
  7. In humoral immunity produces a fast immune response whereas cellular immunity produces a slow immune response.

Conclusion

Therefore we can conclude that both humoral and cellular immunity are the two different active immunization system which works on different criteria.

Both humoral and cellular immunity is the “Mode switching” process that is carried out by our immune system. When there are extracellular pathogens attacking, the immune system of our body switches on the Humoral kind of immunity while the other is switched off. In the processing of intracellular pathogens, our immune system switches on the Cellular kind of immunity by switching off the other.

Therefore, the whole process is based on the principle of mode switching, where the immune system recognizes the type of pathogen and regulate the process of immunity with the help of lymphocyte cells.

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