Archives: Comics

Cartoon of Dendritic Cell and Lymphocyte in the intestine

A big challenge of the immune system in the intestine is being able to distinguish between harmful pathogens and at the same time be tolerant towards harmless antigens derived from food and commensal bacteria (good bacteria). Mechanisms to maintain tolerance are therefore necessary to avoid unwanted immune responses that may lead to inflammatory bowel diseases (IBD) like Crohn’s disease or ulcerative colitis. The dendritic cells (DCs) found in the intestine are crucial to maintaining this equilibrium. DCs are constantly sampling antigens, such as food antigens. One way these cells sample antigens directly from the intestinal lumen is by inserting their dendritic processes between the epithelial cells layer [1].

 

The T cells found in the epithelium located between intestinal epithelial cells are called intraepithelial lymphocytes (IELs) and are thought to contribute to intestinal homeostasis by regulating the turnover of IECs and secreting hormones for epithelial repair [2].

 

Below are some resources in case you are interested in learning more about the immune system in the intestine.

 

References

1. Dendritic cells express tight junction proteins and penetrate gut epithelial monolayers to sample bacteria. Nat Immunol. 2001 Apr;2(4):361-7
2. Intestinal T cells: facing the mucosal immune dilemma with synergy and diversity. Semin Immunol. 2009 Jun;21(3):130-8

 

 

Cartoon of infected cell shedding virus

A virus is a small infectious agent that needs other cells to replicate. The virus gets its genetic material inside the cell and the cell then uses its machinery to read the genetic code and create virus proteins that will form new viral particles.
The cartoon is showing a cell that has been infected and is now producing virus that are being released.

Cartoon of plant cell with chloroplasts, vacuole and cell wall generating glucose

Plant cells and animal cells are both eukaryotic cells. Even though they have a lot of similarities they are different. One of the differences that this cartoon is playing on is the ability of plant cells to generate their own glucose. This is made possible due to the chloroplasts. Animal cells on the other hand need to get their glucose from an outside source.

Just to show how cool the chloroplasts look like below is a video by Microscopic World showing cytoplasmic streaming in plant cells.

 

Neutrophil, a leukocyte phagocytoses bacteria

Neutrophil are the most abundant type of white blood cells and are part of the granulocyte family or the polymorphonuclear cells family.  They get the name ‘polymorphonuclear cells’ because of the varying shapes of the nucleus, which is usually lobed into three segments.

Neutrophils are the first cells to get to the site of infection, they are professional phagocytes and ferocious eaters that rapidly engulf invaders.

Here is a video you can watch of a neutrophil chasing a bacteria.

 

The lab of Dr. Paul Kubes from Calgary University does research on neutrophils. He and his team have published some pretty neat videos of neutrophils moving around tissue. The technique he uses to generate these videos is called intravital microscopy.

In the video below the neutrophils are seen in green migrating through blood vessels (blue) towards an area of tissue damage in the liver (red).

For those who want a more in-depth overview of neutrophils and the latest and most up to date findings here are some resources.

Leukocyte extravasation cartoon cell migration biology

Leukocyte extravasation is the movement of leukocytes out of the circulatory system and towards the site of tissue damage or infection. This process is regulated by a concerted action between endothelial cells and leukocytes, whereby endothelial cells activate leukocytes and direct them to extravasation sites, and leukocytes in turn instruct endothelial cells to open a path for transmigration.

To learn more about leukocyte extravasation and some of the mechanisms involved in this process check out these resources:

Below is a figure from the Nature Immunolog review, that I mentioned above, with an illustration of the steps involved in leukocyte extravasation.

The multistep cascade of leukocyte extravasation. A range of cell adhesion receptors on endothelial cells (as shown at the bottom of the panel) mediates the capture, rolling, arrest and crawling of leukocytes on the luminal endothelial cell surface.

 

References:

Wikipedia

Immunobiology, 5th edition The Immune System in Health and Disease

How leukocytes cross the vascular endothelium Nature Reviews Immunology

 

 

Dendritic Cell Cartoon Immunology

Dendritic cells (DCs) are named after their branched projections called dendrites. These cells are the sentinels of the immune system and are always testing their surroundings in case they see any danger. DCs process antigens they pick up from their surrounding and present these to T cells.

 


 

This video shows how dendritic cells growing in culture are transfected with a plasmid containing a gene for the Green fluorescent protein (GFP).

Transfection is the process of deliberately introducing nucleic acids into eukaryotic cells. Various methods can be used to transfect. Electroporation, shown in this video, is a technique by which an externally applied electrical field applied to the cells makes the plasma membrane of a cell temporarily porous so that molecules such as DNA can pass freely through it.

Once the DNA is inside the cells the genes in this DNA molecule can be “read” by the cell machinery and made into proteins. In this example the molecule DNA entered the cell has information to produce the green fluorescent protein GFP. Therefore the cells that have taken in the DNA can now make GFP and glow green.

More information on
transfection and electroporation
Dendritic cells
GFP

 

 

CD8 CTL Killer T Cell Cartoon

T cells are named after the organ they develop in, the Thymus.

Cytotoxic T cells (CTLs) are a special type of T cells with the ability to kill other cells. Usually they kill cells that have been infected with a virus. This way the virus can no longer use these cells for replicating inside of them. CTLs secrete cytotoxins to kill the other cells and are therefore called “cytotoxic” T cells.

macrophage jumping to engulf bacteria cartoon

Macrophages are white blood cells. The word macrophage comes from the word macros “large” and phagein “eat”. Macrophages are big cells that eat.One of their main roles of these cells is to phagocytose (engulf and then digest) cellular debris and also pathogens such as bacteria. This process is known as PHAGOCYTOSIS. It is a complex mechanism that requires for the macrophage to rearrange its inner cell bits to surround and engulf the target. This animation is a cartoon depicting a macrophage chasing bacteria to ultimately phagocytose them.

B cell Cartoon antibodies white background

Antibody producers

B cells in the human body develop in the bone marrow and are therefore called B cells. These cells are responsible for producing antibodies. The antibodies produced by B cells circulate around our body and bind to specific viruses or bacteria to neutralize them and help get them killed by other cells of the immune system.

Immune Cell Cartoons Macrophage, Dendritic Cell, T Cells and B Cell

I hope you enjoy these cartoons and please feel free to use them in your presentation. A cartoon may provide some entertainment to your audience and also help you get a point across. Just make sure to reference this page so that others know where to find the cartoons.

Enjoy!