Defensive Proteins

Hadley Jones & Jamie Levitt

What are they?Destroy disease causing viruses and bacteriaFight against antigens (substance that stimulates the immune system to produce antibodies)Specific shape that binds with foreign substances to attack itSend signals to other parts of the immune systemExamples: Antibodies and complement proteins

How are they made?

In the cell- transcription and translation provide the genes that make the amino acid sequencetRNA- assembles the protein until the ribosome encounters a “stop” codon Protein synthesis- puts the amino acids together that make up defense proteins The cell’s genes represent the amino acid arrangement to make the protein function properly

Inside the Cell….The genes from DNA are expressed through transcription and translation

Transcription- the information in a gene’s DNA is transferred to the RNA in the nucleus

Translation- takes place in the cytoplasm; the ribosomes read the sequence of mRNA bases

tRNA- assembles the protein by connecting codons in protein synthesis

SHAPE DETERMINES FUNCTION

Antibodies- Y-shaped so they can attach onto foreign substances (antigens)Highly specialized to recognize specific antigensBinding site on each “arm” of the Y Each binding site is specifically shaped (lock and key fitting)Only antigens that match that binding site will fit and get destroyed

ImmunoglobulinMade up of glycoprotein molecules (produced by plasma B cells) in response to an immunogen Functions as an antibodyMain antibody isotope found in blood and fluidsControls infections of body tissueRids the body of pathogens

IgG Antibodies Most common and most importantCirculate in the blood and other body fluidsDefend against invading bacteria and virusesBinding with antigens activates immune cells that engulf and destroy antigensMoves easily across cell membrane

Amino Acid Sequence of IgG1 mkhlwfflll vaaprwvlsq

vqlqesgpgl vkpsetlslt ctvsggsiss hywswirqsp 61 gkglqwigyi yysgstnysp

slksrvtisv etsknqfslk ltsmtaadta vyycar

ITP (idiopathic thrombocytopenic purpura)

Body destroys the platelets as they are made while a typical, healthy platelet is circulates for 9-10 daysCan cause internal and external bleeding without injurySymptoms- red dots on skin, large bruises, bleeding in gums

IgG use for ITPIVIG (intra venous immunoglobulin) is a treatment for ITPThe IgG antibody is used to neutralize the foreign objects such as ITPIVIG is formed by taking IgG antibodies from 2o,ooo donors and mixing them togetherInfusion IVIG has proven to be effective in immune deficiency disorder like ITP IVIG supplies the antibodies for people who cannot make them

SITUATION An ITP (idiopathic thrombocytopenic purpura) (low platelets) antigen is about to invade someone’s blood cells and cause them to have terrible virus for the rest of their life. First group to match all of the antibodies binding sites to the correct antigens stops the ITP antigen and gets a prize!

Websites www.morphosys.com/technologies/antibodies/functionwww.science.howstuffworks.comghr.nlm.nih.gov www.scienceclarified.com

pathmicro.med.sc.eduwww.ncbi.nlm.nih.govwww.itpanswers.comwww.nplate.com/patient/understanding-itp/symptomswww.cidpusa.org/ivig.html