THE BLOOD GROUPS O F MARINE ANIMALS
121
Additional sub-divisions of scores may be added, such as symbols for
uncertain traces of agglutination. The determination of a score,
particularly intermediate ones, involves the evaluation of several
variables and therefore rcquires concentration and judgment and is,
of course, subject to some error. The readings made prove to be
reproducible to a high degree when run in replicate and/or whers
different individuals are given the same materials to score without
any additional information. Research is so conducted as to make
potential aberations in individual readings inconsequential in the
overall analysis of data. The use of controls is, therefore, very important in all blood group research, those that are required varying from
case to case. For example, it is generally desirable to include a control
of erythrocytes in saline alone, or, if isoagglutinins are being studied,
of erythrocytes in their homologous serum to be sure that no aberant
autoagglutination reactions occur. Similarly, normal serum of animals
to be immunized should be tested if one wishes to know whether or
not antibodies are actually induced during the course of immunization. While simple in principle, experience teaches that in practice the
greatest attention must be given to insure that adequate controls are
provided and that familiar ones are not overlooked.
7. The absorption technique
This technique is used extensively in blood group work for the
separation of two or more kinds of antibodies in the same serum. The
volumes of materials dealt with are usually in the order of magnitude
of a few milliliters. Many variations of the technique exist, as each
kind of absorption has its idiosyncrasies. Basically one or two volumes
of serum are inixed with a volume or so of erythrocytes that have
been washed and " packed " by centrifuging. This mixture is kept
agitated either on a rotor or by occasional shaking by hand. The cells
are removed by centrifuging after an hour or so, and the absorbed
Serum tcsted. If antibodies reactive with the absorbing cells remain,
a second absorptioii is carried out. This may be done in the refrigerator
and over a longer period of time. Absorptions can be made using
more than one kind of ccll in a succession, being then termed double,
etc., absorptions. The end result of an absorption should be the
removal of antibodies reactive with the cells employed and the retention of other kinds of antibodies. Care must be taken to avoid the 108s
Of desirable antibodies through '' over-absorption ", that is using too
cells for too long a period of time with a resultant " non-specific "
fbbsorptioii of protein. A delicate regulation of the degree of absorption
'' often necessary, particularly in cases where cross-reactions may
121
Additional sub-divisions of scores may be added, such as symbols for
uncertain traces of agglutination. The determination of a score,
particularly intermediate ones, involves the evaluation of several
variables and therefore rcquires concentration and judgment and is,
of course, subject to some error. The readings made prove to be
reproducible to a high degree when run in replicate and/or whers
different individuals are given the same materials to score without
any additional information. Research is so conducted as to make
potential aberations in individual readings inconsequential in the
overall analysis of data. The use of controls is, therefore, very important in all blood group research, those that are required varying from
case to case. For example, it is generally desirable to include a control
of erythrocytes in saline alone, or, if isoagglutinins are being studied,
of erythrocytes in their homologous serum to be sure that no aberant
autoagglutination reactions occur. Similarly, normal serum of animals
to be immunized should be tested if one wishes to know whether or
not antibodies are actually induced during the course of immunization. While simple in principle, experience teaches that in practice the
greatest attention must be given to insure that adequate controls are
provided and that familiar ones are not overlooked.
7. The absorption technique
This technique is used extensively in blood group work for the
separation of two or more kinds of antibodies in the same serum. The
volumes of materials dealt with are usually in the order of magnitude
of a few milliliters. Many variations of the technique exist, as each
kind of absorption has its idiosyncrasies. Basically one or two volumes
of serum are inixed with a volume or so of erythrocytes that have
been washed and " packed " by centrifuging. This mixture is kept
agitated either on a rotor or by occasional shaking by hand. The cells
are removed by centrifuging after an hour or so, and the absorbed
Serum tcsted. If antibodies reactive with the absorbing cells remain,
a second absorptioii is carried out. This may be done in the refrigerator
and over a longer period of time. Absorptions can be made using
more than one kind of ccll in a succession, being then termed double,
etc., absorptions. The end result of an absorption should be the
removal of antibodies reactive with the cells employed and the retention of other kinds of antibodies. Care must be taken to avoid the 108s
Of desirable antibodies through '' over-absorption ", that is using too
cells for too long a period of time with a resultant " non-specific "
fbbsorptioii of protein. A delicate regulation of the degree of absorption
'' often necessary, particularly in cases where cross-reactions may