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different, subpopulations of lymphocytes in tha alligator and the amphib
ians.
Are Peripheral Blood Lymphocyte Subpopulations T- and B-Cell Equivalents?
As already emphasized in the bluegill studies, designations of T-
and B-cell equivalents in any species must await the association of
functional activities with the in vitro markers established in such
studies. However by analogy, T-like and B-like designations seem
appropriate for the lymphocyte subpopulations established in these
Y
studies. The following discussion is presented to compare the cellular
characteristics of alligator lymphocytes established in these experiments
with in vitro characteristics of bird and mammalian T- and B-lymphocytes.
Using indirect fluorescence microscopy, cytotoxic treatment with
an anti-immunoglobulin and anti-immunoglobulin cellular immunoadsorbents
lymphocytes were found with immunoglobulin on their surface, a B-cell
characteristic in mammals. The latter two techniques were used to show
a diminished response to LPS (a B-cell mitogen) by selectively' removing
the surface immunoglobulin-bearing cells. These results are similar to
those obtained with mammalian B-lymphocytes (24). Although it is pre
dictable that the surface immunoglobulin-bearing cells are also the
cells stimulated by LPS, such a conclusion is not warranted with the
present data. It was not proven directly that cells removed were the
cells stimulated by LPS nor that the surface immunoglobulin-bearing
cells became the immunoglobulin-producing cells (Table 24) in LPS-stimu-
lated cultures. It is conceivable that another cell type acting in
directly was involved. It should be pointed out that an increase in the
number of immunoglobulin-producing cells (B-cells) in LPS-stimulated cul
tures is also observed in mammalian lymphocyte cultures (5,70).