Chapter 16- Adaptive immunity

Phagosome

Neutrophile (non-professional- innate)

Professional phagocytes

1. Macrophage cells: primary professional phagocyte in blood.

2. Dendritic cells: primary profession phagocyte in tissue systems.

3. B cells: Modify membrane to bring bacteria into phagosome. Lysosome vacuoles are around containing protease, lysozymes, and ROS. Phagosome and lysosomes fuse and the bacteria get broke up in phagolysosome. Put component of bacteria onto surfaces of things called MHC;s

MHC 1

Can be triggered in all cells.

MHC 2

Only triggered in professional phagocytes.

T-cells

• Helper T-cells

• Cytotoxic T-cells

  • Both advance in immune reaction

• Regulatory T-cells- shit down immune reaction

Example of professional phagocytes

• Macrophage has MHC II and MHC I on its surface.

• Both MHC’s have a bit of bacteria on them

• Helper T-cells have a T-cell receptor and a second protein called CD4

• CD4 interacts with MHC II

• T-cell receptor interacts with MHC and bacterial component

• We get CD4 interaction with T-cell receptor on MHC II

• Helper T-cell will release cytokines.

• B-cells by the millions on our bodies and each B-cell has unique antibody on its surface

• Small percentage of bacteria from bacterial infection get engulfed by macrophages or dendritic cells. Get presented on MHC and produce cytokines.

• Some bacterial likely to stick to B-cells and B-cell proliferates

• Some B-cells become plasma cells and plasma cells release antibodies.

• Antibodies stick to bacteria which does two things- 1. neutralize bacterial so it can’t do much and 2. opsonization- bacterial with antibodies on it makes them much more easily phagocytized.

• Any bacteria with two antibodies next to each other can trigger natural killer cells which release toxins to kill bacteria.

• Some B-cells don’t become plasma cells but remain memory B-cells.

• Memory B-cells will occupy the spleen and lymph nodes in our body. Next time we get bacterial infection we don’t need a week to produce cells.

• Some memory B-cells become plasma cells and make more memory B-cells.

• Cytotoxic T-cell has a T-cell receptor and a protein called CD8 which allows for interaction with MHC I.

• Cytotoxic cell releases and is now ready to release cytotoxin. Release cytotoxin upon second interaction.

• Cytotoxic T-cell will divide/proliferate

B-cells in bone marrow

Chemical signal you get in bone marrow on B-cells will bind to you and stick to something in the bone marrow like a human protein which causes apoptosis.

Five attributes to adaptive immune system

1. Specificity- unique antibody for specific bacteria

2. Inducible- must be turned on

3. Clonality- we get clones- many of the cells that do work

4. Unresponsiveness to self- any B-cell that does not respond to our self= dead

5. Memory- if we had an infection once, we not have a memory of it where memory B-cells hang out in our spleen and lymph nodes.

Antigens

Trigger the induction of the adaptive immune response. Molecule that body recognizes as foreign and worth of attack. Recognized by three-dimensional regions called epitopes

Opsonization

If you have antibodies on your surface, you are much more easily phagocytized.