Studies of murine large granular lymphocytes. II. Tissue, strain, and age distributions of LGL and LAL.

In the accompanying paper we demonstrate the presence of large granular lymphocytes (LGL) that might be responsible for NK and K activities in the spleen of C3H/ He mice. We also demonstrate large agranular lymphocytes (LAL) that were morphologically similar to LGL with the exception of no granularity in the cytoplasm. In the present study, tissue, strain, and age distributions of LGL and LAL were investigated using a low density fraction after discontinuous density gradient centrifugation by Percoll. LGL, almost all of which were asialo GM1-positive, were distributed in the spleen and peripheral blood with a high NK activity, but in the thymus and lymph nodes there was no or low NK activity. The different frequencies of LGL were detected in organs of mice with different NK activities, such as C3H/He, BALB/c, BALB/ c nu/nu, or C57BL/6, and correlated well with the levels of NK activity in those strains. In contrast, low numbers of LGL were detected in low NK strain A/J mice. With C57BL/6 bg/bg, a genetically deficient strain for NK activity, no typical LGL were found, although LGL with abnormal azurophilic granules showing a single giant dot were identified. The highest frequency of LGL was detected in high NK strain C3H/He mice; those 6 to 8 wk old with the highest NK activity. In the youngest (3 wk) or older (13, 30 wk) mice there was no or low NK activity. On the other hand, LAL, a large portion of which was also asialo GMi-positive and adherent to a NK target (YAC-1), were distributed in the spleen and peripheral blood, as were LGL. A large number of LAL, however, were found even in no or low NK strains and in the younger and aged mice in which no or extremely limited numbers of LGL were found. These results indicate that LGL but not LAL may be actively involved in the NK cytotoxicity.