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Humoral Immunity

Humoral Immunity

Description:

This lesson will investigate an antibody-mediated immune response

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Tutorial

What's Covered

This lesson is going to cover antibody mediated immune response by looking at:

  1. Humoral Immunity
  2. Classes of Antibodies

1.Humoral Immunity

Antibody mediated immune response is a type of adaptive immunity, which is our body's third line of defense against pathogens. In this type of immunity, we are fighting pathogens outside cells in your blood or in your tissue fluids. This is actually unfolding or taking place in our lymphatic system.

  • To summarize what's happening in antibody mediated immune response in one sentence: B-cells in your lymph nodes are producing antibodies to antigens.

Terms to Know

    • Antibody-Mediated Immune Response
    • Also known as humoral immunity, the part of specific immunity that is conducted by B cells. During humoral immunity B cells form into plasma cells that mass produce antibodies to be secreted into our body tissue cavities.
    • Antibodies
    • Specific protein markers that are created by the immune system for binding and reacting to specific antigens; antibodies are created by B cells during humoral immunity.

B-cells are lymphocytes, a type of white blood cell, and they have proteins on their surface. There are generally around 10,000 of these proteins and are called membrane-bound antibodies; they are specific to the type of B-cell. You have different B-cells throughout your body, which have different membrane-bound antibodies, all specific to the type of antigen that they can attach to.

IN CONTEXT
Let's say you were to be invaded by a certain type of virus. That specific type of virus can only be identified by a certain type of B-cell. If a particular B-cell for example doesn't have the right proteins on its surface, other types of B cells will come in here. They'll be bouncing off of this virus until finally one of them fits with this virus and can attach. Let's say that a cell encounters a virus and it binds to it. The B-cell will become activated. Dendritic cells will cause T-cells to divide, and effector helper T-cells will release something called cytokines. Cytokines will help stimulate division of the B-cells into clones of itself.

Term to Know

    • Dendritic Cells
    • A type of phagocyte found in the skin; dendritic cells can also phagocytize (eat) a pathogen or part of a pathogen and display it to a B cell in order to activate it.

When the B-cell becomes active and starts to divide some will be set aside for future attacks as memory B-cells. The others will produce effector B-cells, also known as plasma cells, which make and release antibodies.

Antibodies target invaders, bind to them, and flag them for pickup by phagocytes. Phagocytes will engulf them, and get rid of them. Antibodies can also inhibit normal functioning of the pathogen.

ExampleAntibodies make it harder for a virus to invade a cell, because it has something extra attached to it.


2. Classes of Antibodies

So what we're going to do next is take a look at our five classes of antibodies, and altogether we call these five classes of antibody immunoglobulins.Some of those are secreted, and some of them are membrane-bound.

  • Secreted antibodies are antibodies that are released into the body. Antibodies that these plasma cells make and release are secreted; they're able to freely float throughout the body.
  • Membrane-bound antibodies bind to the membrane of a cell.

Secreted antibodies Include:

  • IgG- the main antibody found in your blood.
  • IgA.- type of antibody that inhibits pathogens from binding to your body's cells. It can be found in your tears, milk, mucus, and saliva.

Membrane-bound antibodies include:

  • IgE- which is anchored to various different types of white blood cells. It plays a huge role in allergies and asthma.
  • IgD and IgM- both B-cell receptors.

Summary

Humoral Immunity, also called the antibody-mediated immune response is a type of adaptive immunity. It fights pathogens outside cells in your body or in your tissue fluids, and takes place in the lymphatic system. B-cells with the right type of protein on its surface can bind to an antigen. It will become active and create more of itself. Some of these cells will be set aside as memory cells for future attacks, while the others will continue to seek out and bind to antigens. These will flag the antigens to be destroyed by phagocytes. The antibodies will also inhibit normal functioning of the antigen. There are five classes of antibodies. Membrane-bound antibodies include IgE, IgD, IgM. Secreted antibodies include IgG and IgA.

Keep up the learning and have a great day!

Source: Source: THIS WORK IS ADAPTED FROM SOPHIA AUTHOR AMANDA SODERLIND

Terms to Know
  • Antibodies

    Specific protein markers that are created by the immune system for binding and reacting to specific antigens; antibodies are created by B cells during humoral immunity.

  • Antibody-Mediated Immune Response

    Also known as humoral immunity, the part of specific immunity that is conducted by B cells. During humoral immunity B cells form into plasma cells that mass produce antibodies to be secreted into our body tissue cavities.

  • Dendritic Cells

    A type of phagocyte found in the skin; dendritic cells can also phagocytize (eat) a pathogen or part of a pathogen and display it to a B cell in order to activate it.