Double diffusion (DD) is based on the principle that antigen and antibody diffuse
through a semisolid medium and form a precipitin l___e. In Ouchterlony's method,
a layer of agar gel is deposited in a petri dish and circular w___s are punched out
near one another in the gel. Antibody is then added to one well while a___n is
added to the other. These materials are allowed to d___e radially from their
respective wells. As the perimeter of the diffusing substance increases, the
concentration of that substance within the perimeter continually
(increases) (decreases). When the optimal concentration of a___n and a____y is
reached, a line of p_____n is formed in the gel. The precipitin line is relatively
s____t and is p_____r to the axis line between the two wells. The immunologic
reactions in double gel diffusion are of (two) (three) types.
Consider this: A solution of the same antigen is placed in two wells and its
corresponding antibody is placed in the center well. Two precipitin bands form,
joining at their contiguous ends and fusing. This is a reaction of i____ty.
To produce a reaction or partial identity, the antigen in one well and the antibody in
the central well are h____s, and the antigen in the other well is a cross-reacting
antigen. The precipitin bands fuse, but in addition form a s_____e that extends
toward the cross-reacting antigen. This is a reaction of p___l i____y.
When two unrelated antigens are placed in adjacent wells and diffuse toward a
central well that contains antibodies for each, two precipitin bands form i_____ly of
each other and c____s. This is a reaction of non-i____y.
Currently, double diffusion is utilized in the clinical laboratory for immune complex
studies and comparing antigens or antibodies for the presence of i__________l or
A screening procedure utilized to detect abnormalities of the various protein
fractions is serum protein e______sis. The patient's serum is applied to a support
medium along with a normal c___l. The agarose gel with the serum applied is
placed in a b____l buffer (pH 8.6) and then subjected to an e____l charge. Due to
the pH of the barbital buffer, the serum proteins will assume a net n_____e
charge. The serum protein components migrate to one of the five possible
characteristic zones (a____n, alpha-1, alpha-2, b__a, and g___a) based upon
their net negative electrical charge, size, and molecular weight. Following a
s_____g procedure using a protein stain, the serum p____n components are
compared to those of the normal control.