3
B-like cells on the basis of graft rejection and antibody production
(discussed in detail later) direct evidence of lymphocyte heterogeneity
in any ectotherm has not been obtained. Furthermore the molecular or
cellular bases for the commonly observed effects of environmental tem
perature on the immune responses of numerous ectotherms (7,37) have not
been investigated.
The purpose of the research undertaken here was to study the char
acteristics of the lymphoid cells from two ectotherms, the bluegill,
a representative teleost, and the Florida alligator, a representative
reptile. The major questions approached were 1) whether these two ani
mals possessed classes of lymphocytes akin to T- and B-cells of higher
animals, 2) whether a cellular basis for the effects of temperature on
the immune response of ectotherms could be obtained, and 3) whether there
are membrane associated immunoglobulins in fish.