88
JOHN E. ausHmG
isoantibodies to distinguish them from the isoimmune antibodies in
isoimmune serums and may or may not be in reagent form without
absorption. Fourth, the serums of some or all individuals of a species
very often contain antibodies reactive with blood group antigens in
other species. These antibodies in normal serums are termed naturd
or normal antibodies (without the prefix of iso- or hetero-) and, like the
other categories of antibodies, may or may not be useful without
absorptive manipulation. (Some kinds of natural antibodies and a180
of isoantibodies are known to fluctuate in their amounts as a result
of environmental influences. This fact makes these antibodies difficult
to use as characters in population research, e.g. see Sindermann and
Honey (1963) and Section 111, C, 7, p. 112.)
An additional category of reagents consists of substances that
cause the specific agglutination of erythrocytes which are not antibodies per se but proteins with antibody-like properties. The most
well known source of such proteins is the seeds of plants of a variety
of species (cf. Bird, 1969), such proteins being termed kctins. Other
sources of agglutinins are microbial and viral products, and the serum
and extracts of invertebrates.
No way has yet been devised that will enable precise advance
predictions as to what sources will yield reagents for particular studies.
A general rule that guides the initial search for antibodies is that thoae
produced by isoimmunization are most likely to be useful inasmuch
as they will recognize antigens not shared by the recipient and donor.
However, it is not always practical to conduct isoimmunizations, end
even when possible good results are not always obtained. The search
for other sources of antibodies and agglutinins usually consists of a
massive screening process, particular selections being guided by previous experience. Some assurance of the success of such a search ie
to be had from the fact that blood group polymorphism haa been
found in nearly all species that have been extensively investigated.
The concentration of antibodies present in a given serum is conveniently expressed in term8 of the degree to which the serum can be
diluted before it fails to react with the erythrocytes involved. This ie
called the titer of a serum and is expressed as e fraction ; a serum, for
example, having a titer of one in five hundred being one in which one
part of serum is still reactive after being diluted five hundred timea.
Serums vary greatly with respect to their titers, some being capable
of many thousand fold dilution, end others of dilutions even less than
one in ten. The titers of antibodies with different specificities in a serum
very independently of each other, so that one may find a high titer for
one and a low titer for another kind of antibody in the same sample.
JOHN E. ausHmG
isoantibodies to distinguish them from the isoimmune antibodies in
isoimmune serums and may or may not be in reagent form without
absorption. Fourth, the serums of some or all individuals of a species
very often contain antibodies reactive with blood group antigens in
other species. These antibodies in normal serums are termed naturd
or normal antibodies (without the prefix of iso- or hetero-) and, like the
other categories of antibodies, may or may not be useful without
absorptive manipulation. (Some kinds of natural antibodies and a180
of isoantibodies are known to fluctuate in their amounts as a result
of environmental influences. This fact makes these antibodies difficult
to use as characters in population research, e.g. see Sindermann and
Honey (1963) and Section 111, C, 7, p. 112.)
An additional category of reagents consists of substances that
cause the specific agglutination of erythrocytes which are not antibodies per se but proteins with antibody-like properties. The most
well known source of such proteins is the seeds of plants of a variety
of species (cf. Bird, 1969), such proteins being termed kctins. Other
sources of agglutinins are microbial and viral products, and the serum
and extracts of invertebrates.
No way has yet been devised that will enable precise advance
predictions as to what sources will yield reagents for particular studies.
A general rule that guides the initial search for antibodies is that thoae
produced by isoimmunization are most likely to be useful inasmuch
as they will recognize antigens not shared by the recipient and donor.
However, it is not always practical to conduct isoimmunizations, end
even when possible good results are not always obtained. The search
for other sources of antibodies and agglutinins usually consists of a
massive screening process, particular selections being guided by previous experience. Some assurance of the success of such a search ie
to be had from the fact that blood group polymorphism haa been
found in nearly all species that have been extensively investigated.
The concentration of antibodies present in a given serum is conveniently expressed in term8 of the degree to which the serum can be
diluted before it fails to react with the erythrocytes involved. This ie
called the titer of a serum and is expressed as e fraction ; a serum, for
example, having a titer of one in five hundred being one in which one
part of serum is still reactive after being diluted five hundred timea.
Serums vary greatly with respect to their titers, some being capable
of many thousand fold dilution, end others of dilutions even less than
one in ten. The titers of antibodies with different specificities in a serum
very independently of each other, so that one may find a high titer for
one and a low titer for another kind of antibody in the same sample.