Infection resistance - The ability of a host to prevent an infection from occurring. 

Infection tolerance - The ability of a host to minimize the harm once an infection has occurred. 

Parasite load - The number of parasites of a given species that an individual host can harbor.

Vertical transmission - When a parasite is transmitted from a parent to its offspring.

TLS Online TPP Program

#Id: 4621

#Unit 13. Methods in Biology

Antibody and soluble antigen interacting in aqueous solution form a lattice that eventually develops into a visible precipitate. Antibodies that aggregate soluble antigens are called precipitins

TLS Online TPP Program

#Id: 4622

#Unit 13. Methods in Biology

 A precipitation curve for a system of one antigen and its antibodies. This plot of the amount of antibody precipitated versus increasing antigen concentrations (at constant total antibody) reveals three zones: 

TLS Online TPP Program

#Id: 4623

#Unit 13. Methods in Biology

A related quantitative technique, rocket electrophoresis, does permit measurement of antigen levels. In rocket electrophoresis, a negatively charged antigen is electrophoresed in a gel containing antibody. The precipitate formed between antigen and antibody has the shape of a rocket, the height of which is proportional to the concentration of antigen in the well.

TLS Online TPP Program

#Id: 4624

#Unit 13. Methods in Biology

One limitation of rocket electrophoresis is the need for the antigen to be negatively charged for electrophoretic movement within the agar matrix

TLS Online TPP Program

#Id: 4625

#Unit 13. Methods in Biology

The interaction between antibody and a particulate antigen results in visible clumping called agglutination. Antibodies that produce such reactions are called agglutinins.

TLS Online TPP Program

#Id: 4626

#Unit 13. Methods in Biology

Agglutination reactions are similar in principle to precipitation reactions they depend on the crosslinking of polyvalent antigens. Just as an excess of antibody inhibits precipitation reactions, such excess can also inhibit agglutination reactions; this inhibition is called the prozone effect.