Results
Lymphoid Organs of the Alligator
Since the Florida alligator is listed by the Florida Game and Fresh
Water Fish Commission as an endangered species, only a limited number
of alligators were available for experimental purposes. Fortunately,it
was easy to obtain large amounts of blood which was an abundant source
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of lymphocytes (1-2 x 10 lymphocytes/ml of whole blood) There were no
detrimental effects to the animals. Evidence will be presented in a
subsequent section that the population of lymphocytes isolated from
peripheral blood are representative (on the basis of mitogenic respon
siveness) of the lymphocytic cells isolated from the spleen.
Two of ten alligators obtained from the Florida Game and Fresh
Water Fish Commission were sacrificed (by special permit) for histologi
cal examinations and in vitro mitogenic studies of the lymphoid organs.
The only recognizable lymphoid organs were the thymus and the spleen.
The thymus was a small whitish organ, approximately 2 x 8 mm located
in the throat. Histological examinations of tissue sections showed an
abundance of lymphocytes and signs of thymic involution were seen. Very
few cells were isolated by Hypaque-Ficoll centrifugation from whole
organ cell suspensions (< 5 x 10^). The spleen of the alligator was
a red, kidney-bean shaped organ, located beneath the stomach, and was
surrounded by a thick capsule. Red and white pulp regions were observed
in tissue sections and a heterogeneous population of white cells was
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