120
JOHN E. CUSHINO
the tube inverted and its opposite end stuck at a 45' angle into a
plasticene strip held in a wooden or plastic block. Several tubes are
arranged in a row in one such strip. This method has the advantage of
being relatively fast and sensitive, and of using smaller amounts of
serums and cells than the other tests. I n addition, the tubes are so
inexpensive as to be disposable. Care must be taken to exclude false
positives that may occur, but this is not of practical concern after some
experience has been acquired.
6. Hemolytic and other techniques
Research on the blood groups of warm blooded vertebrates has
employed to good advantage hemolytic tests in which complement
is added to mixtures of red cells and antibodies. This type of test has
yet to find wide application in the study of marine forms, largely
because the use of complement adds an additional factor to be manipulated and controlled. However, the sensitivity and specificity of
this type of test will undoubtedly prove of value, particularly where
cells are not readily agglutinated (Stormont, 1962).
Other techniques have potential use in studies on marine organisms
but have not yet been exploited to any degree. These include such
methods as the radioactivation of antibody (Fujino and Cushing,
1969), microagglutination and the variety of techniques described in
the general references cited at the beginning of this article.
6. Titration and scoring
As noted in Section 11, B, immunologists use the word titer with
reference to the point to which a reagent can be diluted and still retain
observable reactivity. This point is conventionally measured by making
a series of doubling dilutions of the reagent and testing each dilution.
A titer of 1 in 266 would mean that one part of reagent could be
diluted to one part in 256, without losing all reactivity. A reagent
that could be diluted to this degree would have a high titer, whereaa
one that could only be diluted a little, e.g. 1 in 6, would have 8 loto
titer. While high titers are desirable, low titer serums are also valuable.
The titer of potential reagents should be determined particularly &B
to whether or not this varies with respect to erythrocytes from different
individuals for such variations are evidence of blood group polymorphism.
The degree of agglutination in any one mixture of cells and serum
is oonventionally recorded by systems of plus marks or whole numbera
which usually range from four representing complete agglutination
through to a minus mark or zero representing no agglutination.
JOHN E. CUSHINO
the tube inverted and its opposite end stuck at a 45' angle into a
plasticene strip held in a wooden or plastic block. Several tubes are
arranged in a row in one such strip. This method has the advantage of
being relatively fast and sensitive, and of using smaller amounts of
serums and cells than the other tests. I n addition, the tubes are so
inexpensive as to be disposable. Care must be taken to exclude false
positives that may occur, but this is not of practical concern after some
experience has been acquired.
6. Hemolytic and other techniques
Research on the blood groups of warm blooded vertebrates has
employed to good advantage hemolytic tests in which complement
is added to mixtures of red cells and antibodies. This type of test has
yet to find wide application in the study of marine forms, largely
because the use of complement adds an additional factor to be manipulated and controlled. However, the sensitivity and specificity of
this type of test will undoubtedly prove of value, particularly where
cells are not readily agglutinated (Stormont, 1962).
Other techniques have potential use in studies on marine organisms
but have not yet been exploited to any degree. These include such
methods as the radioactivation of antibody (Fujino and Cushing,
1969), microagglutination and the variety of techniques described in
the general references cited at the beginning of this article.
6. Titration and scoring
As noted in Section 11, B, immunologists use the word titer with
reference to the point to which a reagent can be diluted and still retain
observable reactivity. This point is conventionally measured by making
a series of doubling dilutions of the reagent and testing each dilution.
A titer of 1 in 266 would mean that one part of reagent could be
diluted to one part in 256, without losing all reactivity. A reagent
that could be diluted to this degree would have a high titer, whereaa
one that could only be diluted a little, e.g. 1 in 6, would have 8 loto
titer. While high titers are desirable, low titer serums are also valuable.
The titer of potential reagents should be determined particularly &B
to whether or not this varies with respect to erythrocytes from different
individuals for such variations are evidence of blood group polymorphism.
The degree of agglutination in any one mixture of cells and serum
is oonventionally recorded by systems of plus marks or whole numbera
which usually range from four representing complete agglutination
through to a minus mark or zero representing no agglutination.