Cyclic nucleotide metabolism during lymphocyte transformation. II. Comparative studies in the nude Balb/c mouse.

Lymphocytes from the spleens of nude (athymic) Balb/c mice were incubated with LPS and examined for alterations in cyclic nucleotide metabolism. The cGMP concentration increased to 74% above control values within 20 min after the addition of LPS. cAMP concentration appeared to have two peaks, the first at 10 min to 80% above controls. The increase in cGMP can be accounted for by the inhibition of cGMP degradation by cAMP. These changes in cyclic nucleotide metabolism are similar to those observed in the “normal” Balb/c mouse. There are several differences between the cells from the two groups: (i) a delay in the cAMP and cGMP change and (ii) LPS enhanced cAMP inhibition of cGMP degradation in the nude mouse. These differences may be explained by differences in cell populations in the two mice, other than the obvious lack of T cells. Such differences were found on the basis of cell density distribution, where lymphocytes from normal Balb/c mice were found evenly dispersed between two dextran density gradient fractions, d = 1.057 and 1.066 g/ml; whereas, lymphocytes from nude mice were found almost entirely in the d = 1.066 g/ml fraction.