Transcript Block B Towaki, Brian, Julio, Jeff Antigens and Antibodies

Antigens vs. Antibodies
Brian Keh, Towaki Dojima, Jeff
Gallardo, Julio Villafuerte
Introductory
• Distinguish between antigens and antibodies
• Explain why antibiotics are effective against bacteria but
not against viruses.
Antigens
• Refers to any chemical that can stimulate a
specific immune response
• Protein based molecule on the cell walls and cell
membranes
• Allows for cell communication
• Cells of the same kind have same antigens
• Cells of different kinds have different antigens
• Viruses don’t have antigens
Antibodies
• A protein molecule that binds specifically to antigens
• Also called immunoglobulin
• Made by B-cells (type of white blood cells)
• Each human have around 108 different types
of B-cells. Each antibodies make slightly
different antibodies
Antibodies
• By antibodies binding to antigens
– Make pathogens weaker/recognizable so they are
more ready to be engulfed by phagocytes
– Makes the host cell taken over by viruses
weaker/more recognizable
Antibodies
• Antibodies are Y shaped
Video Clips
• Video link showing and explaining the action of
antibodies:
• http://www.youtube.com/watch?v=Ys_V6FcYD5I
• Video link showing the action of antibodies, no
explanation:
• http://www.youtube.com/watch?v=lrYlZJiuf18&NR=1&fe
ature=fvwp
Explain why antibiotics are effective against bacteria but not
against viruses.
Bacteria
• A type of pathogen
• Has antigens
• Does not need a host
cell to reproduce
Virus
• A type of pathogen
• Does not have antigens
• Needs a host cell to
reproduce
Antibiotics
• Artificially manufactured antibodies.
• Antibiotics cure disease by weakening bacteria
– Occurs through the same methods that antibodies
work on antigens.
• Although antibiotics are useful in a wide
variety of infections, it is important to realize
that antibiotics only treat bacterial infections.
Why don’t antibiotics work on viruses?
• Viruses have different metabolic pathways to
bacteria – so antibiotic drugs have nothing to
target
– Viruses also do not have antigens which are
needed for the antibodies to work.
• Viruses have different structures, e.g. protein
coat instead of cell wall
• Viruses are protected by the host cell
structure
• Viruses use host cell metabolism
Bibliography
• http://www.slideshare.net/gurustip/defenseagainst-infectious-disease-core-presentation
• http://www.emedicinehealth.com/antibiotics/
page5_em.htm