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The results of one experiment designed to test the effects of tem
perature on responsiveness of alligator lymphocytes to PHA are presented
in Figure 8. Cells were cultured with various doses of PHA at the tem
peratures indicated and the optimal dose and the length of time for max
imum stimulation was determined at each temperature. The results indi
cate that the lower the temperature, the longer the time required for
maximum stimulation (indicated in parenthesis). The response of cells
cultured at 22, 35, 37, and 40C was significantly lower (p < 0.01)
than in cells cultured at 27, 30, and 32C. Although responses pf
cells incubated at 27, 30 and 32C were not significantly different
from each other (p > 0.1), the length of time required for optimal stim
ulation of cultures maintained at 32C was shorter (five days) as com
pared with 27 and 30C maintained cultures (seven days). The optimal
mitogen dose was found to be the same at all temperatures. Typical
responses to various mitogen doses and incubation times of alligator
lymphocytes cultured with PHA and LPS at 32C are presented in Figures 9
and 10 respectively. The response to PHA peaked sharply on day 5 and
decreased slowly, whereas the peak response to LPS remained elevated
after reaching an optimum on day 5. Similar experiments were performed
with each of the other mitogens and the results can be summarized by
stating that the optimal temperature tested was found to be 32C, the
length of time for maximum stimulation was five days and the optimal
mitogen dose was the same at each temperature tested. Optimal doses
per culture of LPS, PPD, PWM, PHA and Con A were 10 yg, 10 yl, 1 yl, and
20 yg respectively. It should be pointed out that responses of cells
cultured with 20 yg of Con A varied in different experiments and was
attributed to changes in the lot numbers of Con A used, as well as the