Alicia


 * Biology Experiment**


 * Question(s) for investigation:**

Are antibodies absolutely specific to one type of antigen or can they cross react with similar antigens?


 * Independent variable and how it will be measured:**

The independent variables are the specificity of the antibodies and the epitopes on the antigens


 * Dependent variable(s) and how it (they) will be measured:**

We will be measuring the cross reaction of antigens and if there is an absence or presence of an immune precipitate line.


 * Variables held constant:**

The specificity of the antibodies will be held constant


 * List of Materials and Sketch of the Setup:**

We will need: -petri dish -agar - Goat antihuman IgG (antiserum made in goats injected with human antibodies) -Rabbit IgG (similar) -Human IgG (identical) -Borine serum albumen (no cross reaction)


 * Who else will work on this investigation? Who will be responsible for collecting materials to get started and when will all materials be ready to begin?**

Phil and I are working on this investigation together. He will get the materials needed from his father’s laboratory.


 * Procedure/Method:**

-Prepare a 2% agar in phosphate buffer by dissolving 2g of agar in 98g of phosphate buffer -Heat it till it dissolves -Add some NaN3 (0.1%) as a preservative -Pour into a petri dish and let it sit overnight -Punch 4 holes as shown in the diagram using a glass pipette -Pipette 5 microliters of G H IgG into one hole, 5 microliters of Rabbit IgG into another hole and 5 ml of human IgG into the other. -Let the reaction stand overnight and look for immunoprecipitate lines between the wells


 * Data:**
 * Make a blank data table which you plan to fill out during the investigation
 * What other data do you expect to include in a report of your results?


 * sample ||
 * is immunoprecipitate line present? ||
 * Albumin ||
 * Rabbit IgG ||
 * Human IgG ||
 * Rabbit IgG ||
 * Human IgG ||
 * Rabbit IgG ||
 * Human IgG ||
 * Rabbit IgG ||
 * Human IgG ||
 * Human IgG ||
 * Human IgG ||
 * Human IgG ||
 * Human IgG ||
 * Human IgG ||
 * Human IgG ||

· What do you think might happen and why?
 * Expectations:**

We think that there will be immunoprecipitate lines in between the goat antihuman antibodies and the human IgG as well as the rabbit IgG because there are similar human and the rabbit epitopes, therefore the antihuman antibodies will react with them.

· What other results do you imagine might happen and what would they mean?

If there are no immunoprecipitate lines between either the human IgG or the rabbit IgG then it would mean that the antibodies are absolutely specific and might not always cross react with similar antigens. It could also mean that the human IgG and the rabbit IgG do not have similar epitopes as we previously believed.


 * Communication:**
 * How will you plan to communicate your work clearly to others?
 * What do you expect to accomplish in EACH of the next three class periods in which you can work on this investigation?

We will use the wikispace set up by Mr. Happer to communicate our results to the rest of our class mates. They will be able to see a copy of our plan and a recording of what happens as we continue and finish our experiment. The first class period we will examine and analyze the results of our investigation. We will spend the following two periods updating our wikispaces with results and discussing what else we can do to further our investigation and completing our investigation write-ups.

Albumin- a simple water-soluble protein found in many animal tissues and liquids [Origin: 1590–1600; < LL, equiv. to //alb//(//us//) white, with s. in //-ū-// + //-men// n. suffix                ]
 * Appendix I**

Antibodies- proteins in the blood that are produced by the body in response to specific antigens such as bacteria [Translation of German :, //antagonistic// (from Latin , //anti-//) + , //body//.] [Origin: 1895–1900; [|anti-] + [|body]  ]

Antigens- Any substances that when introduced to the body stimulates the production of an antibody. Antigens include toxins, bacteria, foreign blood cells, and the cells of transplanted organs

Agar-A gelatinous material obtained from marine algae, especially seaweed, used as a medium for growing bacterial cultures in the laboratory and as a thickener and stabilizer in food products. [Origin: 1885–90; < Malay //agaragar// seaweed from which a gelatin is rendered, or the gelatin itself ]

Diffusion- act of being spread out or dispersed [Origin: c.1374, from L. //diffusionem,// from stem of //diffundere// "scatter, pour out," from //dif-// "apart, in every direction" + //fundere// "pour"]

immunodiffusion- any of various analytical techniques that involve antigen and antibody solutions diffusing toward each other in a gel until antibody binds specifically to antigen to form a precipitate. [Origin: 1955–60; [|immuno-] + [|diffusion] ]

epitopes-A localized region on the surface of an antigen that is capable of eliciting an immune response and of combining with a specific antibody to counter that response. [**epi-** + Greek, //place, spot//.]

antiserum- Human or animal serum containing antibodies that are specific for one or more antigens. [Origin: 1900–05; [|anti-] + [|serum] ]

cross reaction- A specific reaction between an antiserum and an antigen complex other than the complex that caused the production of the specific antibodies of the antiserum [Origin: 1945–50 ]

polyclonal antibodies- a mixture of antibodies of different specificities, as in the serum of a person immunized to various antigens [Origin: 1960–65; [|poly-] + clonal ]

specificity- the selective attachment or influence of one substance on another, as an antibiotic and its target organism or an antibody and its specific antigen. [Origin: 1875–80; [|specific] + [|-ity] ]

reaction-the specific cellular response to foreign matter, as in testing for allergies. [origin: 1611, from [|re-] "again, anew" + [|action] (q.v.). Modeled on Fr. //réaction,// older It. //reattione,// from M.L. //reactionem// (nom. //reactio//), from L.L. //react-,// pp. stem of //reagere// "react," from //re-// "back" + //agere// "to do, act" (see [|act]).]

antigen antibody lattice- formed when antigens react with their antibodies and combine to form a huge long chain which makes up the immonoprecipitate line [Middle English, from Old French , from , //lath//, of Germanic origin .]

immunoprecipitate line- a visible line that is formed when a type of antigen reacts with its antibodies [Origin: immuno- + Latin praecipitāre, praecipitāt]

precipitate- A solid or solid phase separated from a solution. [Origin: Latin praecipitāre, praecipitāt-] immunodiffusion- A technique for studying reactions between antigens and antibodies by observing precipitates formed by the combination of specific antigens and antibodies that have diffused in a gel in which they have been separately placed. interaction is manifested by a precipitin line for each system. [Origin__: immuno__- + diffusion] constant- An experimental or theoretical condition, factor, or quantity that does not vary or that is regarded as invariant in specified circumstances. [Origin: Middle English, from Old French, from Latin cōnstāns, cōnstant-, present participle of //cōnstāre//, to stand firm : com-, intensive pref.; see [|com–] + stāre, to stand.]

Appendix II

Cross Reactivity: In the experiment, cross reactivity is one of the main ideas. The purpose of the experiment was to see if antibody antigen reactions are completely specific. We found that they weren’t. This proves that there was cross reactivity between the human and rabbit antigens, which reacted with the goat anti human antibody. The cross reactivity was shown by the immuno- precipitate line that formed between the three wells as shown in the figure below.

Immuno-diffusion: Immuno diffusion is the concept where the contents of the well (the human antigen, rabbit antigen, and goat antihuman antibody) diffuse out. They diffuse until they meet the contents of another well, then if there is any possible reaction between the two then they will react forming the precipitate line, if not then there is no line present.